CXCR3 and COVID-19: It was reported that the proportion of CXCR3– Tfh cells and a cytotoxic Tfh subpopulation negatively correlated with the anti-SARS-CoV-2 antibodies in COVID-19 patients [6, 33, 35], possibly because the Tfh response skewed to CXCR3+ subset, which contributes to anti-SARS-CoV-2 antibody production.