Abstract Background Few studies have investigated the alterations in the T and B cell counts and related subgroups in pulmonary infections especially COVID‐19. Here, we aimed to evaluate total T and B lymphocytes and T cell subgroup counts to find the possible correlation between number of these cells and severity and mortality in COVID‐19 patients. Methods This study was performed on 40 patients with severe COVID‐19 infection confirmed by reverse transcription‐polymerase chain reaction (RT‐PCR) and chest HRCT in August 2020. By the time of admission, T lymphocytes profile in peripheral blood was investigated using multicolor flow cytometry. The total number of T lymphocytes, CD4+ T cells, CD8+ T cells, and B lymphocytes were calculated. Expression of CD2, CD3, CD5, and CD7 as pan T cell surface markers and expression of CD38 and HLA‐DR as activated markers on T lymphocytes were also evaluated. Results Nine patients (22.5%) died during the study and 16 patients (40%) were admitted to ICU. Deceased patients demonstrated lower amounts of T cell count and CD4+ T cell count (with a marginal difference ( p = 0.07)) compared with survived patients at the time of admission. The chance of mortality was significantly higher for patients with CD7 loss (OR = 14.89). A marginally significant relationship was also indicated between CD4<200/ml and mortality (OR = 8.65), but no other significant relationships were observed between variables and ICU admission. Conclusion Altogether, CD7 loss on T lymphocytes and CD4+ T cell count below 200/ml revealed a significant relationship with mortality. Considering T lymphocytes and T cell subgroup count could have a predictive value for patients suffering from COVID‐19. CD7 loss on T lymphocytes and CD4+ T cell count less than 200/ml revealed a significant relationship with mortality in COVID‐19 patients. Considering T lymphocytes and T cell subgroups count could have a predictive value for patients suffering from COVID‐19.
【저자키워드】 COVID‐19, flow cytometry, T lymphocytes, 【초록키워드】 Lymphocytes, Mortality, T cells, severity, CD8+ T cells, pulmonary infections, Predictive value, COVID‐19, Peripheral blood, B cell, T cell, Patient, ICU admission, CD4+ T cells, T lymphocytes, correlation, expression, Admission, CD38, CD4+ T cell, B lymphocyte, Pulmonary infection, marker, B lymphocytes, Predictive, Chain Reaction, subgroup, COVID‐19 patients, These cells, chance, alteration, T and B lymphocytes, T lymphocyte, COVID‐19 infection, HLA‐DR, variable, RT‐PCR, chest HRCT, CD3, Result, evaluate, died, indicated, investigated, evaluated, was performed, calculated, activated, less, demonstrated, significantly higher, survived, these cell, admitted to ICU, CD2, CD5, CD7, surface marker, 【제목키워드】 Mortality, Pneumonia, COVID‐19, Lymphocyte subset, Patient,