key: cord-1030599-stnj48yd
authors: Fukuda, Yosuke; Homma, Tetsuya; Inoue, Hideki; Onitsuka, Chisato; Ikeda, Hitoshi; Goto, Yuiko; Sato, Yoko; Kimura, Tomoyuki; Hirai, Kuniaki; Ohta, Shin; Yamamoto, Mayumi; Kusumoto, Sojiro; Suzuki, Shintaro; Tanaka, Akihiko; Sagara, Hironori
title: Downregulation of type III interferons in patients with severe COVID‐19
date: 2021-04-13
journal: J Med Virol
DOI: 10.1002/jmv.26993
sha: ca269156b43cd4a2d2c37151871b623468d6ffb0
doc_id: 1030599
cord_uid: stnj48yd

Coronavirus disease 2019 (COVID‐19) is globally rampant, and to curb the growing burden of this disease, in‐depth knowledge about its pathophysiology is needed. This was an observational study conducted at a single center to investigate serum cytokine and chemokine levels of COVID‐19 patients, based on disease severity. We included 72 consecutive COVID‐19 patients admitted to our hospital from March 21 to August 31, 2020. Patients were divided into Mild‐Moderate I (mild) and Moderate II‐Severe (severe) groups based on the COVID‐19 severity classification developed by the Ministry of Health, Labor and Welfare (MHLW) of Japan. We compared the patient characteristics as well as the serum cytokine and chemokine levels on the day of admission between the two groups. Our findings indicated that the severe group had significantly higher levels of serum fibrinogen, d‐dimer, lactate dehydrogenase, C‐reactive protein, ferritin, Krebs von den Lungen‐6, surfactant protein (SP)‐D, and SP‐A than the mild group. Strikingly, the levels of interleukin (IL)‐28A/interferon (IFN)‐λ2 were significantly lower in the severe group than in the mild group. We believe that reduced levels of type III interferons (IFN‐λs) and alterations in the levels of other cytokines and chemokines may impact the severity of the disease.

The novel coronavirus disease 2019 (COVID-19) is globally rampant, and more than a billion people to become infected and two million deaths worldwide in less than a year since the first case was identified. However, the pathogenesis of COVID-19 is not fully understood. Because of the high risk of exposure to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), bronchoscopy is not recommended. 1 Therefore, reliable diagnostic and prognostic biomarkers are urgently required. In addition, the biomarkers are likely to lead to new therapeutic targets.

Among the several proposed biomarkers, the newly discovered type III interferons (IFNs), also known as IFN-λs, has been reported to be restrictively produced by airway epithelial cells, hepatocytes, and type 2 myeloid dendritic cells in response to viral infection, and it plays a role in eliminating and limiting the viral load. 2, 3 In the previous report, experiments using a mouse model of acute influenza A infection demonstrated that intranasal IFN-λ2/3 administration reduced the viral load. 4 Furthermore, in a study using samples of COVID-19 nasopharyngeal swabs, the expression of type III IFNs, especially IFN-λ2,3, was decreased by SARS-CoV-2 infection. 5 IFN-λs might, therefore, play a fine-tuning role in providing immunity against viruses and may contribute to the anticytokine storm in COVID-19. 4 However, this has not been proven by experiments with serum samples of COVID-19.

In this study, we evaluated the profiles of COVID-19 patients and their levels of serum cytokines and chemokines based on the disease severity, to discover new targets, especially type III IFNs.

This observational study was conducted at the Showa University Hospital in Japan. We included 72 consecutive COVID-19 patients admitted to the hospital between March 21 and August 31, 2020, who were naive to specific treatments for COVID-19, including remdesivir or favipiravir. 6, 7 The included patients had positive polymerase chain reaction (PCR) test results for COVID-19 from pharyngeal swabs. Disease severity was determined based on the COVID-19 severity classification developed by the Ministry of Health, Labor, and Welfare (MHLW) of Japan (Table S1 ). 8 were considered statistically significant.

Patients in the severe group were significantly older. The symptoms with statistically significant differences between the two groups were dyspnea and loss of taste or smell. Patients in the severe group had significantly higher levels of lymphocyte count, fibrinogen, D-dimer, urea nitrogen, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, potassium, C-reactive protein, ferritin, Krebs von den Lungen-6, surfactant protein (SP)-D, and SP-A, along with significantly lower levels of serum hemoglobin, total protein, albumin, uric acid, and sodium when compared to that of patients in the mild group (Table 1 ). Figure 1 shows the serum levels of cytokines including IFNs on Day 1. Levels of IL-28A/IFN-λ2 were significantly lower in the severe group than in the mild group (p = 0.008; Figure 1E ). On the other hand, there was no statistically significant difference between the two groups for IFN-α (p = 0.138; Figure 1A ), IFN-β (p = 0.961; Figure 1B) , and IFN-γ (p = 0.091; Figure 1C ). Moreover, IL-6 was significantly higher in the severe group than in the mild group (p < 0.001; Figure 1G ).

Strikingly, this is the first report that IL-28A/IFN-λ2 was downregulated in serum samples of severe COVID-19. In a study of respiratory syncytial virus infection of primary bronchial epithelial cell cultures, type I IFNs were not detected, whereas type III IFNs, including IFN-λ1/IL-29, were detected. 9 The severity of rhinovirus infection has also been reported to be inversely correlated with IFN-λ production in asthmatic patients. 9 These in vitro studies revealed the unique properties of type III IFNs. The expression of SARS-CoV-2 RNA was seen to decrease in primary human airway epithelial cells when pretreated with IFN-λ1. 10 Felgenhauer et al. 11 This study showed that patients with severe COVID-19 have high serum levels of IL-6. Furthermore, this study found a correlation between IFN-λ2 and IL-6 (p = 0.027, data not shown), similar to the previous study. 13 Several clinical trials concluded that anti-IL-6 antibody treatment was not useful in COVID-19. 14, 15 It is unclear whether therapeutic intervention for IFN-λs is a treatment option to cytokine storms, including IL-6, and further research should focus on it.

This study has some limitations. First, it was an observational study with a small sample size conducted at a single center, which might have resulted in selection and confounding biases. Future studies should include a larger sample size. Second, we were unable to analyze changes in the levels of cytokines and chemokines over time. Monitoring these changes will allow us to F I G U R E 1 Serum levels of cytokines in the mild and severe group A comparison between serum levels of cytokines including interferons by ELISA in the mild group (n = 50) and the severe group (n = 22) based on the COVID-19 severity classification developed by the Ministry of Health, Labor and Welfare of Japan. Data are shown as median (range). Significance was calculated between two groups (Mann-Whitney U test) study, we are now planning a new study to overcome these limitations.

In summary, levels of IL-28A/IFN-λ2 were lower in patients with severe COVID-19. Downregulation of type III IFN-λs may help in predicting the severity of COVID-19, elucidating its pathogenesis, and developing specific therapies.

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The authors declare that there are no conflict of interests.

This study was performed in accordance with the Declaration of