We found increased Tfh cells [defined as CXCR5+ PD-1hi CD4+ (22)] in the GCs of all patients with HT when compared to controls (13.48 ± 5.27 vs. 5.64 ± 4.65%, respectively, p < 0.05) (Figures 4A top, B). Here, CXCR5 is linked to hematocrit.