key: cord-0915926-sbdxyowx authors: Pakos, Irene; Lo, Kevin Bryan; Salacup, Grace; Pelayo, Jerald; Bhargav, Ruchika; Peterson, Eric; Gul, Fahad; DeJoy, Robert; Albano, Jeri; Patarroyo‐Aponte, Gabriel; Rangaswami, Janani; Azmaiparashvili, Zurab title: Characteristics of peripheral blood differential counts in hospitalized patients with COVID‐19 date: 2020-08-13 journal: Eur J Haematol DOI: 10.1111/ejh.13509 sha: 3bf27244bbac0707fad99f333ea3130881a87947 doc_id: 915926 cord_uid: sbdxyowx BACKGROUND: A lot remains unknown about the features and laboratory findings that may predict worse outcomes in patients with Coronavirus disease 2019 (COVID‐19). The aim of this study was to evaluate the difference in complete blood count parameters and differential counts in patients hospitalized with COVID‐19 who survived compared to those who died. DESIGN: We performed a single center retrospective study including 242 patients with confirmed COVID‐19. We described the characteristics of the complete blood count parameters in these patients. Mann Whitney‐U test was used to compare hematologic parameters of patients who died and those who survived; multivariate logistic regression was used to look for associations with mortality. RESULTS: Patients with COVID‐19 who died had significantly lower median absolute monocyte count (AMC) (0.4 vs 0.5, p=0.039) and median platelet count (169 vs 213, p=0.009) compared to those who survived. Patients who died had a significantly higher neutrophil to lymphocyte ratio (6.4 vs 4.5, p = 0.001). The NLR was positively associated with death (OR=1.038; 95% CI, 1.003 to 1.074, p=0.031) while AMC was inversely associated with death (OR=0.200; 95% CI, 0.052 to 0.761, p=0.018). CONCLUSION: Among patients with COVID‐19, a lower AMC and higher NLR are associated with higher mortality. The pandemic of Coronavirus Disease 2019 (COVID-19), the disease caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus that emerged in Wuhan, China in December 2019 has led to significant mortality in hospitalized patients in most affected parts of the world. In the United States, New York emerged as the epicenter of the pandemic, with New Jersey following as the state with the greatest number of cases 1 . According to the Centers for Disease Control and Prevention (CDC), as of May 2020, in Pennsylvania, there have been more than 57,000 reported cases with the majority of cases in Philadelphia county, which has also seen more than 850 associated deaths 2 . Among patients who are hospitalized with COVID-19, disease severity also varies, with age and comorbidities associated but not fully accountable for poor outcomes. The pathophysiology of disease as well as the mechanisms and factors that lead to differential responses in affected patients including mortality are not entirely elucidated. The development of severe disease is currently thought to be associated with an excessive inflammatory response with several studies reporting association of increased serum levels of inflammatory cytokines and chemokines and higher Accepted Article inflammatory markers [3] [4] [5] [6] . The involvement of monocytes and macrophages in the unraveling of the inflammatory response has also been highlighted as a key component of the response to SARS-CoV-2, although their role remains elusive but could involve the potential for productive replication, or the potential to serve as reservoirs or become vectors for viral dissemination as is the case for other human coronaviruses [7] [8] . Lymphopenia is a feature reported in patients with COVID-19 which is particularly prominent in the presence of severe disease 9 , whereas neutrophilia has been shown to have a positive correlation with the risk of in-hospital death 10 . We therefore sought to explore whether there were substantial differences in the complete blood count parameters and peripheral blood leukocyte differential counts in our sample population with COVID-19 which is predominantly African American. This study was a single center retrospective analysis of all patients >18 years of age who were admitted to Einstein Medical Center Philadelphia from March 1 to April 24, 2020 with a confirmed diagnosis of COVID-19 via reverse transcriptase-polymerase chain reaction assays (RT-PCR) performed on nasopharyngeal swab specimens. Demographic and clinical data, comorbidities, outcomes and laboratory findings including hematologic profile were obtained. The complete blood count and differential analysis were performed at the laboratory of Einstein Medical Center Philadelphia following standard procedures. Institutional review board (IRB) approval was obtained with IRB number: 2020-436. Demographic variables were presented using descriptive statistics and frequencies. Categorical variables were analyzed with chi-square testing. Demographic and clinical variables were tabulated. Kolmogorov Smirnov test was used to determine normality of distribution of data. Data that were skewed were presented as median with interquartile range (IQR) and nonparametric Mann Whitney-U test was used to compare the hematologic variables among those who died compared to those who survived. Multivariable logistic regression was used to evaluate the factors and blood parameters associated with mortality. 95% confidence intervals were used and are presented when appropriate. A total of 389 patients were evaluated in our hospital and tested positive via RT-PCR for COVID-19. 122 patients were excluded who were still admitted at the time of analysis, and 25 patients with incomplete clinical data were excluded leaving a final sample of 242 patients (see Figure 1 ). In the final sample of 242 patients (see Table 1 ), the mean age (+/-SD) was 66 ±14.75. 49% were female and 70% were African American. Chronic medical conditions of these patients included hypertension (74%), diabetes mellitus (49%), and either Chronic Obstructive Pulmonary Disease (COPD) or asthma (19%). Out of our final sample, 26 (11%) patients had a diagnosis of a malignancy. The number of inhospital deaths was 52 (22%). This article is protected by copyright. All rights reserved Looking at the hematologic parameters, patients who died had a significantly lower median absolute monocyte count (AMC) 0.4 x 10 3 (0.2-0.7) vs 0.5 (0.3-0.8), p=0.039 and platelet count 169 x 10 3 (136-229) vs 213 (160-265), p=0.009 compared to those who survived. On the other hand, patients who died had a significantly higher white blood cell (WBC) count 8.0 x 10 3 (6.1-11.5) vs 6.4 x 10 3 (5.0-9.4), p=0.011 and neutrophil to lymphocyte ratio (NLR) 6.4 (4.6-9.9) vs 4.5 (3.1-6.8), p=0.001 compared to those who survived (see table 2 ). There were no significant differences in the hematologic parameters among African Americans vs non-African Americans. In multivariable logistic regression, after adjusting for age, demographics and common comorbidities, NLR was significantly positively associated with inpatient death (OR= 1.038; 95% CI, 1.003 to 1.074, p=0.031) while AMC was significantly inversely associated with inpatient death (OR= 0.200; 95% CI, 0.052 to 0.761, p=0.018). Our study showed that patients who died from the disease had lower levels of monocytes and platelets in peripheral blood samples. A higher NLR was associated with increased mortality while a higher AMC was inversely associated with mortality. Several studies have investigated the characteristics of peripheral blood differential counts of patients with COVID-19 and their association with disease severity. In a study by Yang W et al. 11 , most patients with COVID-19 presented with mild symptoms and peripheral blood analysis showed that 24.2% had leukopenia, 35.6% had lymphopenia and 13.4% of patients had lower than normal range platelet counts. Their study also showed that 22.8% of patients with COVID-19 had lower than normal range neutrophil counts. However, Qin C et al. 9 reported that patients with severe COVID-19 tend to have higher overall leukocyte counts and higher percentage of neutrophils while at the same time having lower lymphocyte counts and lower percentage of monocytes. As a consequence, the NLR tended to be higher in those with severe infection. Another study from Wuhan, China by Mo P et al. 12 showed that patients with refractory COVID-19 had no significant difference in the overall leukocyte count compared to general patients but had significantly higher counts of neutrophils and lower counts of platelets. Monocyte counts were not reported. Liu Y et al. 10 also reported that a higher NLR was associated with a higher risk of inpatient mortality. It seems plausible to argue that leukocyte differential counts vary depending on disease severity with mild disease presenting with leukopenia and neutropenia while severe disease presents with neutrophilia and lymphopenia consistent with our study findings where NLR was significantly associated with mortality. The lymphopenia observed in these patients may reflect massive recruitment of T cells and monocytes to inflamed tissues, the use of steroids, or may be the result of high levels of apoptosis 7 . A case report from a post-mortem analysis from a patient who died from COVID-19, showed substantial interstitial mononuclear inflammatory infiltrates, dominated by lymphocytes in the lungs and heart 13 supporting the concept of lymphocyte depletion from peripheral blood. We also found that non survivors had lower AMC and that it was inversely associated with increased mortality. In contrast, Qin C et al. 9 reported lower percentage of monocytes in patients with severe disease but that AMC was not different between patients with severe disease and general patients. The difference could potentially be attributed to differences in ethnic characteristics of patients included, as 70% of the patients in our study were African American. To our knowledge, this is the first report of the inverse association of AMC with inpatient mortality in patients with COVID- 19. Our finding of lower monocyte counts in non-survivors may represent the result of more extensive tissue inflammation and recruitment of those cells at those sites of inflammation, and possibly direct productive viral infection of these cells as SARS-CoV-2 nucleoprotein has been detected in secondary lymphoid tissue macrophages 14 . Mononuclear phagocytes accounted for as much as 80% of cells in bronchoalveolar lavage fluid (BALF) from patients with severe COVID-19, with an abundance of inflammatory monocyte-derived macrophages 15 . In cases of mild COVID-19, the BALF had a minimal amount of inflammatory monocyte infiltration but rather a predominance of tissue-resident memory T-cells 16 . Merad et al. 7 report that these memory T-cells may have cross-reactivity against SARS-CoV-2 and enable rapid control of the virus thus limiting progression of inflammation and accumulation of macrophages. Thus, it seems like activation of the adaptive immune response is essential in successful control of COVID-19 which can be the result of prior cross reactivity against SARS-CoV-2 as mentioned above while excess activation of just the innate immune response (neutrophils, macrophages, monocytes) 15 can lead to an excessive inflammatory response potentially associated with poor outcomes. Yang X et al. 17 showed that thrombocytopenia is associated with increased risk of in-hospital mortality while Tang et al. 18 showed that platelet count was negatively correlated with mortality. This is consistent with our study findings as well. Thrombocytopenia in COVID-19 can be linked to possible increased consumption of platelets as a large percentage of patients with severe disease develop a coagulopathy that meets criteria for disseminated intravascular hemorrhage 19 . In summary, our study found similar results with increased WBC counts, neutrophils, neutrophil to lymphocyte ratio and decreased platelet counts in patients with severe COVID-19. These findings seem to be consistent even in the setting of a predominantly African American sample population where variations in hematologic parameters such as benign ethnic neutropenia can occur 20 . However, our study found that the AMC is inversely associated with mortality in patients with COVID-19 providing insight into the role of the innate immune system to COVID-19 disease pathophysiology. Limitations to our study would include the relatively small number of patients included and the fact that this was a single center retrospective study. Several patients in our study received treatments either with hydroxychloroquine, corticosteroids, tocilizumab or a combination of these therapies, which may affect the peripheral blood differential counts. We were unable to assess the significance of other hematologic parameters such as hemoglobin, hematocrit and other red blood cell parameters. We were also unable to include peripheral smear characteristics as our data were derived retrospectively from review of electronic medical records and only the actual numerical blood counts were available. In our study sample, Caucasians were underrepresented which may limit generalizability of our study findings. Among patients with COVID-19, a lower AMC is associated with higher mortality. A higher NLR is also associated with increased mortality. This article is protected by copyright. All rights reserved This article is protected by copyright. All rights reserved This article is protected by copyright. All rights reserved PLR= platelet to lymphocyte ratio. This article is protected by copyright. All rights reserved Presenting Characteristics, Comorbidities, and Outcomes Among 5700 Patients Hospitalized With COVID-19 in the New York City Area Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China Clinical and immunologic features in severe and moderate Coronavirus Disease Correlation Analysis Between Disease Severity and Inflammation-related Parameters in Patients with COVID-19 Pneumonia Exuberant elevation of IP-10, MCP-3 and IL-1ra during SARS-CoV-2 infection is associated with disease severity and fatal outcome Pathological inflammation in patients with COVID-19: a key role for monocytes and macrophages Activation of human monocytes after infection by human coronavirus 229E Dysregulation of immune response in patients with COVID-19 in Wuhan, China Neutrophil-to-lymphocyte ratio as an independent risk factor for mortality in hospitalized patients with COVID-19 Clinical characteristics and imaging manifestations of the 2019 novel coronavirus disease (COVID-19):A multi-center study in Wenzhou city Accepted Article Acknowledgements: We want to sincerely thank all the staff that was directly involved in the care of these patients. 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