CD4 and common variable immunodeficiency: The expression of PD-1 on circulating CD4+CD45RA−CXCR5+ T from three CVID patients was similar when evaluated at different time points (patient 8 initial value: 9.9%; after 24 months: 7.3%; patient 32 initial value: 23.9%; after 27 months: 24.8%; patient 25 initial value: 8.7%; after 5 months: 10.0%).