Two different patterns of lymphocyte alterations in critically ill COVID-19 patients

Pathological effects of SARS-CoV-2 on hematological and immunological cells: Alterations in count, morphology, and function

“…Lymphopenia following SARS-CoV-2 infection has been reported in many studies [43] , [44] , [45] , [46] , [47] , [48] , [49] . About 85% of patients who need to be hospitalized have lymphopenia [45] , [50] with a decrease in both T and B lymphocytes [44] , [45] , [51] , [52] , [53] , [54] . However, a study noted that the lymphocyte count remained in the normal range in mild COVID-19 patients [55] .…”

“…The B cell count is not affected by SARS-CoV-2 infection [47] , [55] , [56] even in the severe phase [55] . A decrease in lymphocyte populations can be used as a predictive parameter for determining the severity of the disease and the risk of death in patients with SARS-CoV-2 infection [43] , [50] , [52] , [53] , [54] , [55] , [57] , [58] . However, a recent systematic review found that a low lymphocyte level was correlated with a poor prognosis in general but the association between lymphocyte subsets and the mortality rate of COVID-19 patients was not significant [59] .…”