To quantify peripheral Th1 cells in patients with HT, we first gated on CD3+ CD8- cells as CD4+ T cells owing to the downregulated expression of surface membrane CD4 molecule on PBMCs after being stimulated with PMA and ionomycin27 and then identified IFN-γ+ cells to distinguish Th1 cells from activated PBMCs (Fig. 1A). The gene discussed is CD8A; the disease is hematocrit.