Upregulation of PD-1 Expression and High sPD-L1 Levels Associated with COVID-19 Severity

Figure 1

Upregulation of PD-1 in lymphocytes and monocytes of patients with COVID-19. Strategy of the analyses for TCD4+, TCD8+, CD19+, and monocytes expressing PD-1 (a); absolute values of total lymphocytes in patients with moderate (), severe (open symbol, ), and critical (red symbol, ) disease and healthy control () (b). Frequency of total lymphocytes (c), CD4+ CD3+ T-cells (d), CD4+ PD-1+ T-cells (e), CD8+ CD3+ T-cells (f), CD8+ PD1+ T-cells (g), CD19+ cells (h), CD19+ PD-1+ cells (i), total monocyte frequency (j), and CD14+ PD-1+ cells (k) assessed by flow cytometry in peripheral blood samples of control subjects () and patients in moderate (), severe (open symbol, ), and critical (red symbol, ) clinical status. , , and .

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