In vitro generation of COVID-19-specific T-cells from a subset of participants trended towards increased cytotoxic CD4+ and CD8+ T-cell activity in seroconverters and dysfunctional COVID-19-specific T-cell responses in non-seroconverters.<h4>Conclusions</h4>These results suggest that HM patients have impaired T-cell immunity, and non-responders may be identified by low levels of serum CXCL13 and CRTAM. This evidence concerns the gene CRTAM and COVID-19.