The link between cTFhs and antibody production has been clearly demonstrated; CXCR5+PD1+CXCR3− cTfhs are correlated with anti-HIV antibody development (14), whereas CXCR5+CXCR3+ICOS+ cTfhs are associated with the development of antibodies after seasonal influenza vaccination by providing help to memory B cells (18). This evidence concerns the gene CXCR5 and influenza.