CD4 and activated PI3K-delta syndrome: Immunophenotyping of APDS patients revealed CD4+ T cells lymphopenia, with a decrease in naive CD4+ and CD8+ T cells' count and a concomitant increase in effector memory CD8+ T cells' count resulting in normal to high counts of CD8+ T cells and a subsequent inverted CD4/CD8 ratio (8, 9, 32) Table 2.