key: cord-0924409-embb0dzi
authors: Theoharides, Theoharis C.
title: Ways to Address Perinatal Mast Cell Activation and Focal Brain Inflammation, including Response to SARS-CoV-2, in Autism Spectrum Disorder
date: 2021-08-29
journal: J Pers Med
DOI: 10.3390/jpm11090860
sha: 1e973a4f5ead21aecb557ec31a0819c1d8ed5e58
doc_id: 924409
cord_uid: embb0dzi

The prevalence of autism spectrum disorder (ASD) continues to increase, but no distinct pathogenesis or effective treatment are known yet. The presence of many comorbidities further complicates matters, making a personalized approach necessary. An increasing number of reports indicate that inflammation of the brain leads to neurodegenerative changes, especially during perinatal life, “short-circuiting the electrical system” in the amygdala that is essential for our ability to feel emotions, but also regulates fear. Inflammation of the brain can result from the stimulation of mast cells—found in all tissues including the brain—by neuropeptides, stress, toxins, and viruses such as SARS-CoV-2, leading to the activation of microglia. These resident brain defenders then release even more inflammatory molecules and stop “pruning” nerve connections, disrupting neuronal connectivity, lowering the fear threshold, and derailing the expression of emotions, as seen in ASD. Many epidemiological studies have reported a strong association between ASD and atopic dermatitis (eczema), asthma, and food allergies/intolerance, all of which involve activated mast cells. Mast cells can be triggered by allergens, neuropeptides, stress, and toxins, leading to disruption of the blood–brain barrier (BBB) and activation of microglia. Moreover, many epidemiological studies have reported a strong association between stress and atopic dermatitis (eczema) during gestation, which involves activated mast cells. Both mast cells and microglia can also be activated by SARS-CoV-2 in affected mothers during pregnancy. We showed increased expression of the proinflammatory cytokine IL-18 and its receptor, but decreased expression of the anti-inflammatory cytokine IL-38 and its receptor IL-36R, only in the amygdala of deceased children with ASD. We further showed that the natural flavonoid luteolin is a potent inhibitor of the activation of both mast cells and microglia, but also blocks SARS-CoV-2 binding to its receptor angiotensin-converting enzyme 2 (ACE2). A treatment approach should be tailored to each individual patient and should address hyperactivity/stress, allergies, or food intolerance, with the introduction of natural molecules or drugs to inhibit mast cells and microglia, such as liposomal luteolin.

ASD is characterized by difficulties in communication and apparently purposeless repetitive movements [1] [2] [3] [4] [5] . The prevalence is estimated to be 1 in 54 children in the United States [6, 7] and is associated with enormous economic burden [8] [9] [10] [11] . However, ASD pathogenesis is still unknown. Moreover, most children with ASD have a number of comorbidities such as hyperactivity, gastrointestinal problems, allergies, and seizures [12] [13] [14] , making the development of effective treatments difficult and prompting the need for a personalized approach [15] .

A number of risk factors during gestation [16] , especially pre-eclampsia [17] [18] [19] , preterm birth, and low birth weight [20] [21] [22] , as well as atopic conditions, autoimmune diseases, [23] [24] [25] infection, and psychological stress, have been increasingly associated with higher risk of ASD in the offspring (Table 1) [26, 27] . There have been many reports of different aspects of immune dysfunction in ASD [28] [29] [30] [31] [32] . In fact, maternal antibodies have been implicated in brain pathology in ASD [33] , especially autoantibodies against proteins in the developing fetal brain [34] [35] [36] . We had proposed that focal inflammation in the amygdala may contribute to ASD [37-39] via activation of microglia [40] [41] [42] [43] . The present manuscript is organized in different parts, stressing certain risk factors such as SARS-CoV2 infection, psychological stress, atopic conditions, and finally, treatment approaches. 57] • High fever [58, 59] • Hypothyroidism [24] • Infection [58, 60, 61] • Inflammation [38, 39] • Low birth weight/preterm birth [16, [20] [21] [22] 62] • Pre-eclampsia [17] [18] [19] • Mastocytosis [63] • Psoriasis [23] [24] [25] • Rheumatoid arthritis [24] • Stress [16, 62, [64] [65] [66] [67] [68] [69] [70] [71] [72] 

Infections [58, 60, 61] and high fever [58, 59] during gestation have been associated with higher risk for ASD. However, there is very little information available on the effect of viruses, especially SARS-CoV-2, on the fetus. Viral proteins can interact with placenta cells [73] . One recent paper that reviewed findings from 101 women infected with SARS-CoV-2 reported that there is vertical transmission of SARS-CoV-2 from the mother to the infant, with adverse effects on the newborn [74] . However, two other papers reported negligible transmission [75, 76] . However, transmission may not be required for the virus to induce neuroinflammation, as it may affect peripheral nerves [77] or the developing brain via the Spike protein directly affecting brain cells [78] .

Recent publications reported increased perinatal complications in mothers infected with SARS-CoV-2 [56, 79] , especially pre-eclampsia [79] and premature birth [56, 79] , associated with inflammatory responses [80, 81] . Pre-eclampsia is characterized by high levels of corticotropin-releasing hormone (CRH) [82, 83] , which is typically secreted from the hypothalamus under stress [84] . With respect to children infected with SARS-CoV-2, even though they have milder pulmonary symptoms than adults [85-91], a number of papers have reported the presence of Multisystem Inflammatory Syndrome in children (MIS-C) [92-94] and adolescents [95] . In such cases, symptoms typically occur 4-6 weeks after infection and are reminiscent of Kawasaki disease [96] but also include neurologic involvement [97] . Moreover, the clinical presentation is associated with elevated markers of inflammation and the presence of multiple autoantibodies [98] , and one paper suggested that MIS may be a form of mast cell activation syndrome (MCAS) presenting with neuropsychiatric symptoms and brain fog [57] . In fact, perinatal brain inflammation [99] can contribute to the pathogenesis of neuropsychiatric disorders [100,101], including ASD [16, 38, 102] . Moreover, it is now recognized that as many as 50% of those infected with SARS-CoV-2 [126] develop a post-acute syndrome known as "long-COVID syndrome" [127] [128] [129] . This syndrome is particularly associated with neurologic and psychiatric symptoms, especially brain fog, [128, [130] [131] [132] , as well as persistent fatigue apparently independent of the severity of the initial symptoms [133] . In fact, the Simons Fnd. (New York, NY, USA) recently announced the funding of longitudinal studies of mothers infected with maternal COVID-19 for increased risk for ASD. (https://www.sfari.org/grant/maternal-covid-19-as-a-potential-risk-for-autismsupplemental-funding-for-ongoing-pregnancy-cohorts-request-for-applications/ (accessed on 1 June 2021).

The detrimental effects of stress, inflammation, and auto-immunity were discussed recently [134], especially with respect to COVID- 19 [113] and mast cells [135] . A number of subsequent reviews have discussed neurobiological aspects [136] and neuroinflammation in the context of ASD [137] [138] [139] . In this paper, we discuss how environmental and stress stimuli trigger fetal or neonatal mast cells to secrete proinflammatory mediators, leading to focal inflammation in the amygdala, regulating emotions and fear ( Figure 1) [140] and contributing to ASD [38, 45, 141] . We further propose a set of laboratory tests and approaches to better identify comorbidities and help each individual to be the best they can be. Diagrammatic representation of how SARS-CoV-2 could stimulate fetal mast cells and result in inflammation of the brain. SARS-CoV-2 could stimulate fetal or neonatal mast cells especially in the nose and enter the brain via the olfactory nerve tract, reaching the amygdala. There, it could further activate mast cells and microglia to release pro-inflammatory mediators, thus contributing to brain inflammation and ASD. Luteolin could block these processes.

Psychological stress can have pro-inflammatory effects [64, 134] via CRH [142] stimulating mast cells [135] . One study showed that prenatal and early postnatal stress were associated with elevated serum levels of IL-6 in humans [143] . Another study reported that acute psychological stress increased the circulating levels of proinflammatory cytokines [144] . A longitudinal study of mothers' serum measurements during gestation linked IL-6 to decreased executive function in their offspring [145] . We had shown that acute restraint stress significantly increased serum IL-6 in mice, which was entirely dependent on mast cells [146] . It is interesting that IL-6 has also been reported to promote human mast cell production and reactivity [147] . Moreover, prenatal stress or exposure to IL-6 resulted in increased microglia ramification in mice and was prevented by IL-6 blockade [148] .

Psychological stress could also lead to increased vascular permeability [135] . This process also contributes to the disruption of the blood-brain barrier (BBB) [149, 150] via release of CRH [151] and IL-6 [152] , permitting entry into the brain of viral particles, cytokines, or other toxic substances, thus further exacerbating brain inflammation. Breakdown of the BBB has been reported in the developing brain following inflammation [153] . We further showed that restraint stress in rodents increased BBB permeability [149, 150, 154, 155] via CRH stimulating mast cells [154, 156, 157] . The BBB typically prevents circulating toxic substances, but also immune cells, from entering the brain. The BBB is not fully developed until the third trimester [158] [159] [160] and is more vulnerable to toxins and drugs [161] . It was recently shown that common drugs such as acetaminophen (paracetamol) and cimetidine can enter the fetal brain in higher amounts than the adult brain [162] . Moreover, umbilical cord blood biomarkers indicative of acetaminophen exposure were significantly associated with the risk of ASD in childhood [163] . Hence, many atopic or pathogenic conditions, including exposure to certain drugs, could influence brain development during pregnancy or even lactation.

Stress associated with COVID- 19 [134] can further affect the emotional state of individuals [118,119, [164] [165] [166] [167] , especially social isolation, loneliness, and anxiety [168] . One study reported that prenatal stress was linked to higher risk of newborns developing attention-deficit hyperactivity disorder (ADHD) [65, 66] and ASD [67] [68] [69] [70] [71] [72] . A more recent study of 1638 pregnant women concluded that a high level of perceived stress through pregnancy, especially during the second trimester, was associated with an increased risk of the offspring developing ASD at 6 months of age [62] . Prenatal stress may lead to maternal immune dysregulation, thus contributing to ASD [70] . It is interesting that maternal psychological stress during pregnancy increased cord blood levels of IgE [169] , suggesting that it could contribute to an increased risk in the fetus of developing allergic reactions or sensitivity to postnatal exposure to allergens. Psychological stress also increased the risk of childhood atopic dermatitis (AD) [170, 171] and asthma [172] [173] [174] . To make matters worse, children with ASD cannot handle stress [175, 176] and have an exacerbated sense of fear [39].

Infection with SARS-CoV-2 is primarily characterized by the release of a storm of pro-inflammatory cytokines [177] [178] [179] [180] [181] [182] [183] [184] [185] , especially IL-6 [186] [187] [188] [189] and IL-1β [190, 191] . Mast cells are a key source of such cytokines in COVID-19 [192] [193] [194] [195] and could contribute to interstitial lung edema and immunothromboses [196] .

We reported that children born to mothers with systemic mastocytosis [63] , which is characterized by a greater number of hyperactive mast cells than in the general population [197] , had a higher risk of developing ASD [1, 2, 7, 198, 199] . The word atopy is commonly used to denote a tendency, usually early in life, to become sensitized to and produce immune IgE to environmental antigens. Many epidemiological studies reported a strong association between atopic diseases and behavioral problems in general [200] and in ASD in particular [46, 47] . Other epidemiological studies showed a strong association between risk for developing ASD and allergies [45,46,48-50], especially asthma [50,53] and atopic dermatitis (AD) [54] , but also food hypersensitivity [12, [201] [202] [203] [204] [205] . In fact, the presence of allergies was associated with elevated serum levels of autoantibodies against brain antigens in children with ASD [206] . Parental history of AD was strongly associated with children developing AD [207] . It was reported that maternal immune activation [208] and autoimmune diseases [209] , especially psoriasis, but also allergies and asthma, were associated with a higher risk of ASD [23] . In another study, almost 50% of children with ASD had relatives with rheumatoid diseases as compared to 26% in the control group [210] . In a recent large study, mothers who suffered from asthma, allergy, atopy, or eczema during pregnancy were associated with a higher risk of neuropsychiatric problems in children [55] . Three recent studies reported strong associations with ASD and food allergy [211] and food intolerance [202] that could lead to brain inflammation and cognitive impairment [212] .

A recent publication showed that the mother's circulating immune IgE resulted in vertical transmission of AD in the newborn via stimulation of fetal mast cells [213] ; both passive and active prenatal sensitization conferred allergen sensitivity [213] . This important paper indicated that fetal mast cells were functional and could be stimulated by specific IgE and allergens present in the mother during gestation. Even though these studies were limited to pulmonary and skin mast cells, reactivity could also extend to brain mast cells. In fact, prenatal allergen exposure was even shown to program lifelong changes in adults rats' social and sexual behavior, including effects on microglia activation and neonatal dendritic spine density [214] . Fetal mast cells could potentially respond to other stimuli such as neuropeptides and toxins, including the alarmin IL-33 [215, 216] , with detrimental effects on brain development, especially in premature babies [16] . Activated brain mast cells have been shown to contribute to cognitive dysfunction via microglia activation and neuronal apoptosis [217] . Mast cells are ubiquitous in the body [218] and are critical for allergic diseases [219] , including mastocytosis [197] . However, mast cells also participate in inflammation [220, 221] by secreting histamine and multiple pro-inflammatory cytokines and chemokines [222, 223] , including IL-1β [224] , IL-6 [225] , and TNF [226] . Mast cells are also present in the brain, especially the meninges [227, 228] and the median eminence [229] , where they are located perivascularly, close to nerve endings positive for CRH [227] . We showed that stress stimulates mast cells via CRH [135] leading to increased dura vascular permeability, an effect that was absent in mast celldeficient mice [230] . Moreover, mast cells can activate the hypothalamic-pituitary-adrenal (HPA) axis [142, [231] [232] [233] via the release of histamine [234] , IL-6 [152] , and CRH [151] . Moreover, neurotensin [235] and substance P (SP) [236] , neuropeptides implicated in inflammation, induced CRHR-1, thus creating an autocrine loop. Moreover, SP induced the ST2 receptor for IL-33 [226] , further exacerbating mast cell activation by the combined action of neuropeptides and IL-33.

Mast cells respond not only to allergic but also to many other stimuli that can act alone or increase mast cell reactivity [197] . Mast cells can also be triggered by viruses [237] including SARS-CoV-2 [192, 195] . In fact, gene expression of the coronavirus surface receptor angiotensin-converting enzyme 2 (ACE2) was recently shown to be induced by interferon [238] , and mast cells can elicit strong pro-inflammatory and Type I interferon responses in the presence of viruses [239] , implying an autocrine action on ACE2 expression. Following stimulation, mast cells release large amounts of pro-inflammatory mediators [222] such as histamine, tryptase, chemokines (e.g., CCL2, CCXL8) [240] , and cytokines (IL-6, [225] IL-1β [224] , TNF [226] ), especially when primed by IL-33 [216, 241] . Histamine can stimulate macrophages to release IL-1 [242] , which in turn stimulates mast cells to release IL-6 [225] . Mast cells can also secrete mitochondrial DNA (mtDNA) extracellularly [243] , which serves as an alarmin and can stimulate pro-inflammatory mediator secretion from immune cells [244, 245] . We reported elevated extracellular mtDNA in the serum of children with ASD [246] . In fact, it was recently reported that mtDNA may mediate prenatal environmental influences in ASD [247] , was increased in the serum of COVID-19 patients, and correlated with disease severity [248] . Moreover, mast cells synthesize and release platelet-activating factor (PAF), which has been implicated in inflammation [249] and microthromboses [250] characterizing COVID-19. In fact, a recent paper reported a strong association across the globe with SARS-CoV-2 infection rates and levels of pollen known to be involved in upper respiratory system allergies, thus implicating mast cell activation [251] 

Microglia are specialized resident macrophages of the Central Nervous System (CNS) with important functions in both health and disease. They are especially implicated in neuroinflammation [252] [253] [254] and neurodegenerative [252, [255] [256] [257] diseases. Activation of microglia has been reported in ASD [41] [42] [43] 258] , as documented by the release of the pro-inflammatory mediators IL-1β and CXCL8 [259] . Microglia were recently implicated in COVID-19 [260] and were also associated with neuroinflammation [261] . The transition of microglia from the resting to the activated proinflammatory phase is regulated by several intrinsic and extrinsic factors. Microglia can be activated by numerous molecules including pathogen-associated molecular patterns (PAMPs) and endogenous damage-associated patterns (DAMPs) acting on Toll-like receptors (TLRs), but also in response to molecules released from mast cells, such as histamine and tryptase ( Table 2) [39]. It was recently reported that elevated protein synthesis in microglia resulted in autism-like synaptic and behavioral changes in mice [262] . A dysfunctional neuroimmune cross-talk may result in a state of chronic fetal microglial activation leading to a disruption of neurogenesis and synaptic pruning [263] , processes critical for the development of ASD. 

Mast cells interact with microglia in the brain [264] , leading to their activation [264] [265] [266] [267] and to neuroinflammation [266, 268] . This effect is absent in mast cell-deficient mice [39, 269] . Activation of mast cells [270, 271] and microglia [272] , especially in the hypothalamus [273] , could lead to cognitive dysfunction [274] . Microglia express receptors for CRH [275] and could be further activated by stress, especially in association with COVID-19 [276] . Microglia also express receptors for neurotensin (NT) ( Table 2 ) [277] . We reported that NT is increased in the serum of patients with ASD [278, 279] and can activate human microglia to secrete pro-inflammatory molecules [259] . We also reported increased gene expression of the pro-inflammatory microRNA-155 (miR-155) in the amygdala of children with ASD [280] , as well as reduced expression of the anti-inflammatory cytokine IL-38 [281] . Microglia also express TLRs [282] and were recently implicated in COVID-19 [260, 283] .

It is critical to identify the presence of any atopy or allergies and food intolerance, especially the presence of Mast Cell Activation Syndrome (MCAS) [284, 285] or systemic mastocytosis (SM) [197] , by measuring the levels of the molecules listed in Table 3 . Of note is IgG4 because it is involved in food intolerance and has been reported to be elevated in the plasma of children with ASD [286] . 

• Tryptase Urine collected for 24 h or first morning void (must be kept and sent cold)

* Should be measured after one week of NO antacids, otherwise there is a high chance of false positive results. Elevated chromogranin A is not indicative of atopy, but of a somewhat similar condition called carcinoid syndrome associated with activated enterochromaffin cells in the gut.

It is also important to avoid histamine-rich foods, especially ripe tomatoes and avocados, cheeses, spinach, tangerines, spices, and sardines, which have been associated with histamine intolerance [287] . In this context, it is useful to conduct gene analysis for metabolizing enzymes, especially diamine oxidase (DAO), which breaks down histamine, and enzymes that break down phenols such as monoamine oxidase (MAO), catecholamineortho-methyl transferase (COMT), and phenol sulfur transferase (PST) to ascertain phenol intolerance that can contribute to hyperactivity. If DAO gene expression is defective and/or its activity in the blood is low, DAO supplements can be added about 30 min before meals, but one should be careful to avoid the common dyes and preservatives mentioned below.

Unfortunately, many medications, supplements, and vitamins contain "inactive" ingredients that are not tolerated by many children with ASD, leading to unexpected or worsening of behaviors. Such ingredients to be avoided include dyes, preservatives, gluten, monosodium glutamate (MSG), polyethylene glycol (PGE), galactosaccharide (GOS), salicylates, silicum, soy talc, and Twin 80. In addition, herbicides such as glyphosate and atrazine should be avoided, as they have been reported to stimulate mast cells and promote inflammation [288] , besides their known neurotoxic effects.

One should choose the best tolerated antihistamine [289, 290] from the list shown in Table 4, especially rupatadine, which also blocks mast cells, [291] [292] [293] , and avoid large doses that may lead to confusion [294] . In fact, the Food and Drug Administration (FDA) recently warned that taking higher-than-recommended doses of diphenhydramine (Benadryl) can lead to serious heart problems, seizures, coma, or even death. https://www.fda.gov/drugs/ drug-safety-and-availability/fda-warns-about-serious-problems-high-doses-allergy-medicinediphenhydramine-benadryl (accessed on 1 June 2021). As discussed, anxiety, fear, and stress are major factors leading to hyperactivity. This should be investigated (by measuring total blood catecholamines and glutamate) and addressed with the use of a chamomile/passiflora/valerian extract or Ashwagandha [295, 296] . If these are not sufficient, one should consider the beta-blocker propranolol that has good anti-anxiety properties without clouding the mental abilities and has also been reported to improve language in children with ASD [297] . Alternatively, one may recommend the use of alpha 2-receptor agonists [298] such as clonidine [299, 300] and guanfacine [301, 302] , usually administered at bedtime especially since clonidine reduces sleep initiation latency and night awakening [303] . Moreover, caution should be exercised because such adrenergic blocking drugs may cause bradycardia and a drop in blood pressure. Cannabidiol (CBD) oil may be useful but it should be used with caution in individuals with atopic problems, because it has been reported to trigger the activation of cultured leukemic mast cells [304] .

There has been considerable progress in defining drugs that block tyrosine kinases (TK) that are involved in mast cell proliferation [305] . The use of biologics for TNF [306, 307] and IL-1β, [308] ; has significantly improved the treatment of inflammatory skin diseases. However, these agents have a number of limitations as they may cause paradoxical inflammation, reduced ability to fight infection, and cancer development [309] . In spite of such advances, there is no clinically effective inhibitor of human mast cell mediator secretion. Moreover, inhibitors of the tyrosine kinase c-kit receptor that reduce MC proliferation [310] do not inhibit mast cell activation [311] . There are still no clinically effective mast cell inhibitors [221, 312] . Disodium cromoglycate (cromolyn), known as a "mast cell stabilizer," had originally been shown to inhibit rat peritoneal MC histamine release [313] . However, cromolyn does not effectively inhibit either murine MC [314] or human MC [315] [316] [317] and has even been reported to potentiate histamine release from mast cells [318] .

Instead of cromolyn, one should choose the best purity, source, and formulation of the flavonoids luteolin and quercetin [319] [320] [321] [322] [323] . These flavonoids are readily available and are generally considered safe [45, [324] [325] [326] . Luteolin has broad anti-viral properties [327] [328] [329] and inhibits the entry of the corona virus into host cells [237, 330, 331] . Furthermore, luteolin better penetrates into the brain, inhibits both microglia [259, [332] [333] [334] and mast cells [317, 335] , is neuroprotective [336] [337] [338] [339] , and has been reported to reduce neuroinflammation [337, [340] [341] [342] and cognitive dysfunction [61, [343] [344] [345] , especially brain fog [346] . In fact, flavonoids were recently shown to improve cerebral cortical oxygenation and cognition in healthy adults. [347, 348] Moreover, flavonoids induce the synthesis and secretion of neurotrophic factors, including brain-derived neurotrophic factor (BDNF) [77, 349, 350] , known to be deficient in certain conditions associated with ASD, such as RETT syndrome [351] . The beneficial actions of luteolin are summarized in Table 5 . • Antagonizes SARS-CoV-2 Spike protein binding [237, 330, 331, 352] • Has broad antiviral properties [327] [328] [329] • Improves cerebral cortical oxygenation and cognition [347, 348] • Induces the synthesis and secretion of BDNF [77, [349] [350] [351] • Inhibits serine proteases required for Spike protein processing [353, 354] • Inhibits neuroinflammation [340] [341] [342] • Inhibits the release and action of PAF [249, 250] • Inhibits mast cell stimulation by different triggers [317, 335] • Inhibits microglia activation [259, [332] [333] [334] • Interferes with coronavirus replication [355] • Is neuroprotective [336] [337] [338] [339] • Reduces cognitive decline [61, [343] [344] [345] [346] • Reduces oxidative stress [320] • Regulates inflammasome activation [356] * Methoxyluteolin is more potent, metabolically stable, enters the brain more efficiently, and is better tolerated due to the absence of phenolic groups.

Luteolin and quercetin are not water-soluble and are difficult to absorb in powder form after oral administration [357] , but their intestinal uptake can be greatly improved [358] in liposomal preparations using olive pomace oil [358] . In fact, such a luteolin formulation in olive pomace oil (NeuroProtek ® ) has been reported to improve ASD [359, 360] , while another one (BrainGain ® ) reduced brain fog [344] . The latter formulation also provided the additional neuroprotective [361] [362] [363] [364] [365] [366] and anti-inflammatory [367, 368] actions of olive pomace oil polyphenols, as well as the increase in memory induced by the olive oil component hydroxytyrosol [365, 369] .

The beneficial actions of these supplements could be combined with that of a unique, hypoallergenic skin lotion containing tetramethoxyflavone (GentleDerm ® ) [305] , which can be applied on the forehead for direct absorption by temporal blood vessels. Tetramethoxyflavone (methoxyluteolin, methlut) is a more potent inhibitor of human mast cells than either quercetin of luteolin [317, 335] and also inhibits human microglia [259, 333] .

The natural molecule berberine may be particularly useful in cases of PANS/PANDAS because of its antibacterial properties, but also because it can inhibit mast cells [370, 371] and improve brain circulation [372] . In addition, high doses of Vitamin D3 are recommended, because this vitamin has been found to be present at low levels in mothers and/or children with ASD [371, [373] [374] [375] and also decreases atopic responses [376] . When all fails, intravenous Ig may be administered [289] .

It is critical to try to address each child individually (Table 6) [377] by first identifying any comorbidity, especially atopic diseases and hyperactivity, as well as any metabolic issue especially related to vitamins B1, B6, B12, folic acid/MTHFR, thyroid, or vitamin D3 deficiency, since these may be easily overcome. Inflammation of the brain may be reduced with the use of the natural flavonoid luteolin, especially when formulated in liposomal form in olive pomace oil that significantly increases oral absorption (BrainGain ® , PureLut ® , NeuroProtek ® with FDA Certificate of Free Sale). The beneficial actions of these supplements could be augmented by the use of a unique, hypoallergenic skin lotion (GentleDerm ® ), which contains the more potent methoxyluteolin and can be applied on the temples for direct absorption by brain blood vessels. Thus, inhibiting the activation of mast cells and microglia not only would prevent vertical transmission of atopic disorders, but also may prevent inflammation of the brain and reduce the risk of the offspring developing neuropsychiatric disorders, especially ASD (US patents US 7, 906, 153; 8, 268, 365; 9050275) . 

Identification and evaluation of children with autism spectrum disorders

Autism spectrum disorder: Consensus guidelines on assessment, treatment and research from the British Association for Psychopharmacology

Neuropsychological assessment in autism spectrum disorder

Autism spectrum disorders

Prevalence of autism spectrum disorder among children aged 8 years-Autism and developmental disabilities monitoring network, 11 sites

Prevalence of autism spectrum disorder among US children and adolescents

The epidemiology and global burden of autism spectrum disorders

Brief report: Forecasting the economic burden of autism in 2015 and 2025 in the United States

Costs of autism spectrum disorders in the United Kingdom and the United States

The economic costs of autism spectrum disorder: A literature review

Autism spectrum disorders: Concurrent clinical disorders

Medical comorbidities in autism: Challenges to diagnosis and treatment

Autism spectrum disorder diagnosis in adults: Phenotype and genotype findings from a clinically derived cohort

Paving the way toward personalized medicine: Current advances and challenges in Multi-OMICS approach in autism spectrum disorder for biomarkers discovery and patient stratification

Perinatal stress, brain inflammation and risk of autism-Review and proposal

Maternal hypertensive disorders and neurodevelopmental disorders in offspring: A population-based cohort in two Nordic countries

Preeclampsia and neurodevelopmental outcomes: Potential pathogenic roles for inflammation and oxidative stress?

Prenatal and perinatal metabolic risk factors for autism: A review and integration of findings from population-based studies

Preterm or early term birth and risk of autism

Screening for autism spectrum disorders in extremely preterm infants

Autism and preterm birth: Clarifying risk and exploring mechanisms

Maternal autoimmune diseases, asthma and allergies, and childhood autism spectrum disorders: A case-control study

Family history of autoimmune diseases is associated with an increased risk of autism in children: A systematic review and meta-analysis

Risk of attention deficit hyperactivity and autism spectrum disorders among the children of parents with autoimmune diseases: A nationwide birth cohort study

Risk factors in autism: Thinking outside the brain

The emerging clinical neuroscience of autism spectrum disorder: A review

COVID-19 and multisystem inflammatory syndrome, or is it mast cell activation syndrome?

Interaction between maternal immune activation and antibiotic use during pregnancy and child risk of autism spectrum disorder

Perinatal complications as predictors of infantile autism

Prenatal maternal infection and risk for autism in offspring: A meta-analysis

Luteolin could improve cognitive dysfunction by inhibiting neuroinflammation

Association between maternal perceived stress in all trimesters of pregnancy and infant atopic dermatitis: A prospective birth cohort study

Autism spectrum disorders and mastocytosis

Effect of stress on neuroimmune processes

Prenatal maternal stress associated with ADHD and autistic traits in early childhood

Maternal psychosocial stress and children's ADHD diagnosis: A prospective birth cohort study

Colman, I. The association between prenatal stress and externalizing symptoms in childhood: Evidence from the avon longitudinal study of parents and children

Timing of prenatal stressors and autism

Maternal migration and autism risk: Systematic analysis

Prenatal stress and maternal immune dysregulation in autism spectrum disorders: Potential points for intervention

The fears, phobias and anxieties of children with autism spectrum disorders and Down syndrome: Comparisons with developmentally and chronologically age matched children

Prenatal stress, maternal immune dysregulation, and their association with autism spectrum disorders

Pregnancy and pandemics: Interaction of viral surface proteins and placenta cells

SARS-CoV2 vertical transmission with adverse effects on the newborn revealed through integrated immunohistochemical, electron microscopy and molecular analyses of Placenta

Perinatal outcome and possible vertical transmission of coronavirus disease 2019: Experience from North India

Tooth wear in a sample of community-dwelling elderly Greeks

Modulation of neurotrophic signaling pathways by polyphenols

Be aware of SARS-CoV-2 spike protein: There is more than meets the eye

Maternal and neonatal morbidity and mortality among pregnant women with and without COVID-19 infection: The INTERCOVID multinational cohort study

SARS-CoV-2 infection in pregnancy is associated with robust inflammatory response at the maternal-fetal interface

SARS-CoV-2 infection and COVID-19 during pregnancy: A multidisciplinary review

Role of corticotropin-releasing hormone in onset of labour

Mast cell activation and autism

Mast cells as targets of corticotropin-releasing factor and related peptides

Prenatal and early postnatal stress and later life inflammation

The effects of acute psychological stress on circulating and stimulated inflammatory markers: A systematic review and meta-analysis

Maternal IL-6 during pregnancy can be estimated from newborn brain connectivity and predicts future working memory in offspring

Stress-induced interleukin-6 release in mice is mast cell-dependent and more pronounced in Apolipoprotein E knockout mice

IL-6 promotes an increase in human mast cell numbers and reactivity through suppression of suppressor of cytokine signaling 3

A new role for placental IL-6 signalling in determining neurodevelopmental outcome

Corticotropin-releasing hormone and the blood-brain-barrier

Blood-brain barrier and intestinal epithelial barrier alterations in autism spectrum disorders

Corticotropin-releasing hormone and its structurally related urocortin are synthesized and secreted by human mast cells

Recombinant interleukin-6 activates the hypothalamic-pituitary-adrenal axis in humans

Breakdown of the blood-brain barrier to proteins in white matter of the developing brain following systemic inflammation

Corticotropinreleasing hormone (CRH) and brain mast cells regulate blood-brain-barrier permeability induced by acute stress

Autism, gut-blood-brain barrier and mast cells

Brain metastases of mouse mammary adenocarcinoma is increased by acute stress

Impact of stress and mast cells on brain metastases

Ontogeny of the blood-brain barrier

Barrier mechanisms in the developing brain

Embryonic blood-cerebrospinal fluid barrier formation and function

Recent developments in understanding barrier mechanisms in the developing brain: Drugs and drug transporters in pregnancy, susceptibility or protection in the fetal brain?

Determinants of drug entry into the developing brain

Association of cord plasma biomarkers of in utero acetaminophen exposure with risk of attention-deficit/hyperactivity disorder and autism spectrum disorder in childhood

Vicarious traumatization in the general public, members, and non-members of medical teams aiding in COVID-19 control

Treatment concerns for psychiatric symptoms in patients with COVID-19 with or without psychiatric disorders

Mental health care for medical staff and affiliated healthcare workers during the COVID-19 pandemic

Letter to the Editor "A longitudinal study on the mental health of general population during the COVID-19 epidemic in China

Rapid systematic review: The impact of social isolation and loneliness on the mental health of children and adolescents in the context of COVID-19

Prenatal negative life events increases cord blood IgE: Interactions with dust mite allergen and maternal atopy

Maternal psychologic problems increased the risk of childhood atopic dermatitis 1. Pediatr

Prenatal maternal stress and atopic diseases in the child: A systematic review of observational human studies

Prenatal stress, prematurity, and asthma

Evidence establishing a link between prenatal and early-life stress and asthma development

Prenatal maternal psychological stress and childhood asthma and wheezing: A meta-analysis

Anxiety disorders and obsessive-compulsive disorder in individuals with autism spectrum disorder

Emotion regulation in autism spectrum disorder: Where we are and where we need to go

The pathogenesis and treatment of the 'Cytokine Storm' in COVID-19

Clinical and immunological features of severe and moderate coronavirus disease 2019

Induction of pro-inflammatory cytokines (IL-1 and IL-6) and lung inflammation by Coronavirus-19 (COVI-19 or SARS-CoV-2): Anti-inflammatory strategies

Complex immune dysregulation in COVID-19 patients with severe respiratory failure

Cytokine storm in COVID-19: The current evidence and treatment strategies

COVID-19 and the immune system

The COVID-19 cytokine storm

Immune determinants of COVID-19 disease presentation and severity

Highways to hell: Mechanism-based management of cytokine storm syndromes

Elevated levels of IL-6 and CRP predict the need for mechanical ventilation in COVID-19

Profiling serum cytokines in COVID-19 patients reveals IL-6 and IL-10 are disease severity predictors

Impaired immune cell cytotoxicity in severe COVID-19 is IL-6 dependent

Prognostic value of interleukin-6, C-reactive protein, and procalcitonin in patients with COVID-19

The role of IL-6 and other mediators in the cytokine storm associated with SARS-CoV-2 infection

Coronavirus-19 (SARS-CoV-2) induces acute severe lung inflammation via IL-1 causing cytokine storm in COVID-19: A promising inhibitory strategy

Mast cells contribute to coronavirus-induced inflammation: New anti-inflammatory strategy

COVID-19, pulmonary mast cells, cytokine storms, and beneficial actions of luteolin

Covid-19 hyperinflammation and post-Covid-19 illness may be rooted in mast cell activation syndrome

Potential association of mast cells with COVID-19

Mast cells in alveolar septa of COVID-19 patients: A pathogenic pathway that may link interstitial edema to immunothrombosis

Mast cells, mastocytosis, and related disorders

Epidemiology of pervasive developmental disorders

Autism and related disorders

Allergic diseases in preschoolers are associated with psychological and behavioural problems

Food allergy and autism spectrum disorders: Is there a link? Curr

Association of food hypersensitivity in children with the risk of autism spectrum disorder: A meta-analysis

Association of food allergy and other allergic conditions with autism spectrum disorder in children

Parent-reported prevalence of food allergies in children with autism spectrum disorder: National health interview survey

Diet: The keystone of autism spectrum disorder?

The possible relationship between allergic manifestations and elevated serum levels of brain specific auto-antibodies in autistic children

How does parental history of atopic disease predict the risk of atopic dermatitis in a child? A systematic review and meta-analysis

Maternal immune activation: Implications for neuropsychiatric disorders

Immune mediated conditions in autism spectrum disorders

Familial clustering of autoimmune disorders and evaluation of medical risk factors in autism

Role of Milk-Derived Opioid Peptides and Proline Dipeptidyl Peptidase-4 in Autism Spectrum Disorders

Food allergy induces alteration in brain inflammatory status and cognitive impairments

Fetal mast cells mediate postnatal allergic responses dependent on maternal IgE

Mast cells in the developing brain determine adult sexual behavior

Targeting IL-33 in autoimmunity and inflammation

Effect of IL-33 on de novo synthesized mediators from human mast cells

Activated brain mast cells contribute to postoperative cognitive dysfunction by evoking microglia activation and neuronal apoptosis

Developmental origin and functional specialization of mast cell subsets

Mast cells signal their importance in health and disease

The development of allergic inflammation

Mast cells and inflammation

Mast cells as sources of cytokines, chemokines, and growth factors

Interleukin-1 family cytokines and mast cells: Activation and inhibition

Substance P and IL-33 administered together stimulate a marked secretion of IL-1beta from human mast cells, inhibited by methoxyluteolin

IL-1 induces vesicular secretion of IL-6 without degranulation from human mast cells

SP and IL-33 together markedly enhance TNF synthesis and secretion from human mast cells mediated by the interaction of their receptors

Morphological and functional demonstration of rat dura mast cell-neuron interactions in vitro and in vivo

Mast cells in meningiomas and brain inflammation

Definitive characterization of rat hypothalamic mast cells

Stress-induced dura vascular permeability does not develop in mast cell-deficient and neurokinin-1 receptor knockout mice

Brain mast cells act as an immune gate to the hypothalamic-pituitary-adrenal axis in dogs

Degranulation and decrease in histamine levels of thalamic mast cells coincides with corticosterone secretion induced by compound 48/80

Nasal provocation of patients with allergic rhinitis and the hypothalamic-pituitary-adrenal axis

Studies on the involvement of histamine in the hypothalamic-pituitary-adrenal axis activation induced by nerve growth factor

Neurotensin and CRH interactions augment human mast cell activation

Substance P (SP) induces expression of functional corticotropin-releasing hormone receptor-1 (CRHR-1) in human mast cells

Mast cell responses to viruses and pathogen products

SARS-CoV-2 receptor ACE2 is an interferon-stimulated gene in human airway epithelial cells and is detected in specific cell subsets across tissues

Mast cells elicit proinflammatory but not type I interferon responses upon activation of TLRs by bacteria

IL-33 stimulates human mast cell release of CCL5 and CCL2 via MAPK and NF-kappaB, inhibited by methoxyluteolin

The role of IL-33 and mast cells in allergy and inflammation

Mast cells activated by SARS-CoV-2 release histamine which increases IL-1 levels causing cytokine storm and inflammatory reaction in COVID-19

Stimulated human mast cells secrete mitochondrial components that have autocrine and paracrine inflammatory actions

Endogenously oxidized mitochondrial DNA induces in vivo and in vitro inflammatory responses

Mitochondrial DAMPs increase endothelial permeability through neutrophil dependent and independent pathways

Mitochondrial DNA and anti-mitochondrial antibodies in serum of autistic children

Mitochondria may mediate prenatal environmental influences in autism spectrum disorder

Circulating mitochondrial DNA is an early indicator of severe illness and mortality from COVID-19

COVID-19, microthromboses, inflammation, and platelet activating factor

Coronavirus 2019, microthromboses, and platelet activating factor

Higher airborne pollen concentrations correlated with increased SARS-CoV-2 infection rates, as evidenced from 31 countries across the globe

Microglia-mediated neuroinflammation in neurodegenerative diseases

Microglia function in the central nervous system during health and neurodegeneration

Microglia in central nervous system inflammation and multiple sclerosis pathology

Microglia in neurodegenerative disease

How neuroinflammation contributes to neurodegeneration

Microglia in neurodegeneration

Elevated protein synthesis in microglia causes autism-like synaptic and behavioral aberrations

Neurotensin stimulates sortilin and mTOR in human microglia inhibitable by methoxyluteolin, a potential therapeutic target for autism

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and glial cells: Insights and perspectives

Neuropathobiology of COVID-19: The role for glia. Front

Anti-SARS-CoV IgG response in relation to disease severity of severe acute respiratory syndrome

Immune regulation of neurodevelopment at the mother-foetus interface: The case of autism

Mast cells in neuroinflammation and brain disorders

Neuroinflammation, microglia and mast cells in the pathophysiology of neurocognitive disorders: A review

Neuroinflammation, mast cells, and glia: Dangerous liaisons

Induction of microglial activation by mediators released from mast cells

Mast cells, brain inflammation and autism

Suppression of brain mast cells degranulation inhibits microglial activation and central nervous system inflammation

The role of mast cells in Alzheimer's disease

Mast cells in stress, pain, blood-brain barrier, neuroinflammation and Alzheimer's disease. Front

Microglia in Alzheimer's disease

Myalgic encephalomyelitis/chronic fatigue syndrome-metabolic disease or disturbed homeostasis due to focal inflammation in the hypothalamus?

Maternal allergic inflammation in rats impacts the offspring perinatal neuroimmune milieu and the development of social play, locomotor behavior, and cognitive flexibility

Functional expression of corticotropin-releasing hormone (CRH) receptor 1 in cultured rat microglia

The relationship between perceived stress and subjective cognitive decline during the COVID-19 epidemic

Neurotensin and the neurotensin receptor-3 in microglial cells

Neurotensin is increased in serum of young children with autistic disorder

Elevated serum neurotensin and CRH levels in children with autistic spectrum disorders and tail-chasing Bull Terriers with a phenotype similar to autism

Increased expression of miR-155p5 in amygdala of children with Autism Spectrum Disorder

IL-38 inhibits microglial inflammatory mediators and is decreased in amygdala of children with autism spectrum disorder

TLR signaling tailors innate immune responses in human microglia and astrocytes

Severe acute respiratory syndrome Coronavirus 2 impact on the central nervous system: Are astrocytes and microglia main players or merely bystanders? ASN Neuro

Mast cell activation syndrome: Proposed diagnostic criteria

Recent advances in our understanding of mast cell activation-Or should it be mast cell mediator disorders?

Increased IgG4 levels in children with autism disorder

Histamine and histamine intolerance

Glyphosate-rich air samples induce IL-33, TSLP and generate IL-13 dependent airway inflammation

A systematic review and meta-analysis of immunoglobulin g abnormalities and the therapeutic use of Intravenous Immunoglobulins (IVIG) in autism spectrum disorder

Allergy, histamine and antihistamines

Rupatadine inhibits proinflammatory mediator secretion from human mast cells triggered by different stimuli

Rupatadine inhibits inflammatory mediator release from human LAD2 cultured mast cells stimulated by PAF

Rupatadine improves quality of life in mastocytosis: A randomized, double-blind, placebo-controlled trial

Antihistamines and mental status

Ashwagandha in brain disorders: A review of recent developments

A systematic review of the clinical use of Withania somnifera (Ashwagandha) to ameliorate cognitive dysfunction

Effect of propranolol on word fluency in autism

alpha2-adrenergic agonists or stimulants for preschool-age children with attention-deficit/hyperactivity disorder

Clonidine as a treatment of behavioural disturbances in autism spectrum disorder: A systematic literature review

Systematic review and meta-analysis of pharmacological treatment of the symptoms of attention-deficit/hyperactivity disorder in children with pervasive developmental disorders

A randomized, placebo-controlled trial of extendedrelease guanfacine in children with autism spectrum disorder and ADHD symptoms: An analysis of secondary outcome measures

Guanfacine monotherapy for ADHD/ASD comorbid with Tourette syndrome: A case report

Use of clonidine in children with autism spectrum disorders

Cannabidiol, unlike synthetic cannabinoids, triggers activation of RBL-2H3 mast cells

Controlling mast cell activation and homeostasis: Work Influenced by Bill Paul that continues today

The translational revolution and use of biologics in patients with inflammatory skin diseases

Etanercept as monotherapy in patients with psoriasis

Anti-interleukin-31 receptor a antibody for atopic dermatitis

Treatment strategies for early psoriatic arthritis

Inhibition of c-kit receptor tyrosine kinase activity by STI 571, a selective tyrosine kinase inhibitor

Efficacy and safety of midostaurin in advanced systemic mastocytosis

Twenty-first century mast cell stabilizers

Antiallergic drug cromolyn may inhibit histamine secretion by regulating phosphorylation of a mast cell protein

Evidence questioning cromolyn's effectiveness and selectivity as a 'mast cell stabilizer' in mice

Quercetin is more effective than cromolyn in blocking human mast cell cytokine release and inhibits contact dermatitis and photosensitivity in humans

Topical sodium cromoglicate relieves allergen-and histamine-induced dermal pruritus

The novel flavone tetramethoxyluteolin is a potent inhibitor of human mast cells

Potentiation of histamine release by sodium cromoglycate

Flavonols inhibit proinflammatory mediator release, intracellular calcium ion levels and protein kinase C theta phosphorylation in human mast cells

Anti-oxidant, anti-inflammatory and anti-allergic activities of luteolin

The roles of flavonoles/flavonoids in neurodegeneration and neuroinflammation

Flavonoids as cytokine modulators: A possible therapy for inflammation-related diseases

A critical review of the data related to the safety of quercetin and lack of evidence of in vivo toxicity, including lack of genotoxic/carcinogenic properties

Safety of quercetin for clinical application (Review)

Safety aspects of the use of quercetin as a dietary supplement

Identification of luteolin as enterovirus 71 and coxsackievirus A16 inhibitors through reporter viruses and cell viability-based screening

Antiviral activity of luteolin against Japanese encephalitis virus

Luteolin decreases the yield of influenza A virus in vitro by interfering with the coat protein I complex expression

Roles of flavonoids against coronavirus infection

A role for quercetin in coronavirus disease 2019 (COVID-19)

Apigenin and luteolin modulate microglial activation via inhibition of STAT1-induced CD40 expression

Luteolin reduces IL-6 production in microglia by inhibiting JNK phosphorylation and activation of AP-1

Dietary luteolin reduces proinflammatory microglia in the brain of senescent mice

Methoxyluteolin inhibits neuropeptide-stimulated proinflammatory mediator release via mTOR activation from human mast cells

Neuroprotection by flavonoids. Braz

Neuroprotective effects of flavone luteolin in neuroinflammation and neurotrauma

Luteolin protects the hippocampus against neuron impairments induced by kainic acid in rats

The flavone luteolin improves central nervous system disorders by different mechanisms: A review

Pleiotropic Effects of Isoflavones in Inflammation and Chronic Degenerative Diseases

Brain inflammation, neuropsychiatric disorders, and immunoendocrine effects of luteolin

The Pharmacological Action of Kaempferol in Central Nervous System Diseases: A Review

Polyphenols as an effective therapeutic intervention against cognitive decline during normal and pathological brain aging

Brain "fog", inflammation and obesity: Key aspects of 2 neuropsychiatric disorders improved by luteolin

Flavonoid-mediated presenilin-1 phosphorylation reduces Alzheimer's disease beta-amyloid production

Long-COVID syndrome-associated brain fog and chemofog: Luteolin to the rescue

Dietary flavanols improve cerebral cortical oxygenation and cognition in healthy adults

Long-term dietary flavonoid intake and subjective cognitive decline in US men and women

8-Dihydroxyflavone as a pro-neurotrophic treatment for neurodevelopmental disorders

Flavonoids induce the synthesis and secretion of neurotrophic factors in cultured rat astrocytes: A signaling response mediated by estrogen receptor

Dysregulated brain immunity and neurotrophin signaling in Rett syndrome and autism spectrum disorders

Small molecules blocking the entry of severe acute respiratory syndrome coronavirus into host cells

Inhibition of SARS-CoV 3CL protease by flavonoids

A structural mechanism of flavonoids in inhibiting serine proteases

Pharmaceutical interventions in chronic fatigue syndrome: A literature-based commentary

Regulatory roles of flavonoids on inflammasome activation during inflammatory responses

Protective role of luteolin against cognitive dysfunction induced by chronic cerebral hypoperfusion in rats

Luteolin supplements: All that glitters is not gold

An open-label pilot study of a formulation containing the anti-inflammatory flavonoid luteolin and its effects on behavior in children with autism spectrum disorders

Children with Autism Spectrum Disorders, who improved with a luteolin containing dietary formulation, show reduced serum levels of TNF and IL-6

Phytochemistry: Ibuprofenlike activity in extra-virgin olive oil

Bioactivity of olive oil phenols in neuroprotection

Olive polyphenols: New promising agents to combat aging-associated neurodegeneration

Olive biophenols reduces Alzheimer's pathology in SH-SY5Y cells and appswe mice

Hydroxytyrosol, the major phenolic compound of olive oil, as an acute therapeutic strategy after ischemic stroke

Olive oil phenols and neuroprotection

Modulation of cytokine secretion by pentacyclic triterpenes from olive pomace oil in human mononuclear cells

Phenolic compounds characteristic of the mediterranean diet in mitigating microglia-mediated neuroinflammation. Front

Hydroxytyrosol: A natural compound with promising pharmacological activities

Berberine suppresses IL-33-induced inflammatory responses in mast cells by inactivating NF-kappaB and p38 signaling

Berberine suppresses mast cell-mediated allergic responses via regulating FcvarepsilonRImediated and MAPK signaling

Berberine facilitates angiogenesis against ischemic stroke through modulating microglial polarization via AMPK signaling

Vitamin D levels in children and adolescents with autism

Vitamin D Deficiency in Autism Spectrum Disorder: A Cross-Sectional Study

The association between vitamin D status and Autism Spectrum Disorder (ASD): A systematic review and meta-analysis

Vitamin D and atopy