In vitro, GC Tfh cells are more susceptible to infection with HIV‐1 than non‐GC Tfh cells or CXCR5− extrafollicular CD4+ T cells,170, 171 and in vivo they have been shown to constitute the major CD4 T‐cell compartment for virus replication in both HIV‐1 172, 173 and SIV174, 175 infections. This evidence concerns the gene CXCR5 and infection.