CD4 and lymphopenia: Finally, the expression of PD-1 was increased with lymphopenia in CD4+ and CD8+ T cells and in those subsets related to homeostasis: CD4+ naïve T cells, CD4 recent thymic immigrants, CD4 TSCM and CD8 naïve T cells (Supplementary Figure S5) Importantly, CD4+ TSCM also had increased CD57 expression suggesting an increased proportion of senescent cells with lymphopenia (Supplementary Figure S5, p= 0.042, r=- 0.22).