Cell counts (A) and cell proportions (B) of lymphocyte subset, consist of CD3⁻CD16⁺CD56⁺, CD3⁺CD4⁺, CD3⁺CD8⁺, CD3⁻CD19⁺ and CD3⁺,which represents NK cell, CD4⁺T cell, CD8⁺T cell, total B lymphocyte and total T lymphocyte, respectively, of healthy control (as HC) (male = 7, female = 14), common viral CAP cases (as VP) (male = 30, female = 24) and the COVID-19 patients (as nCoV) (male = 13, female = 23) classified into two categories by sex: male and female. Statistical comparisons are indicated by the arrows; ns., non-significant; Comparisons were done by the Mann–Whitney U test. *P<0.05; **P<0.01; ***P<0.001; ****P<0.0001.