Fig. 4.

Kinetic analysis of cell counts of different lymphocyte subsets in COVID-19 patients. The kinetic changes of different lymphocyte subsets in the peripheral blood of COVID-19 patients were measured from the disease onset up to 18 days later. Flow cytometric analysis to for CD3⁺ T cells, CD4⁺ and CD8⁺ T cell subsets, B cells and NK cells was performed. The initial lymphocyte counts and CD3⁺, CD4⁺ and CD8⁺ T cell counts at admission in patients according to age (a) and the presence of comorbidities (b). c The CD3⁺, CD8⁺ and CD4⁺ T cell counts in patients with mild and severe disease at 3–5 days after the disease onset. d The absolute numbers of CD3⁺ T cells, CD8⁺ T cells, CD4⁺ T cells, B cells and NK cells in the peripheral blood of mild (blue line) and severe (red line) COVID-19 patients were analyzed at different time points after the disease onset. *P < 0.05; **P < 0.01; ***P < 0.001. The median and quartile intervals (a–c) or means ± SD (d) are given in the graph. Results were tested for significance by two-way ANOVA (a), t test (b), Mann–Whitney U test (c) and t test or Mann–Whitney U test (d). A P value < 0.05 is considered as significant