CD8A and cytomegalovirus infection: In contrast, a recent study [33] reported a higher incidence of HCMV infection and disease one month after peripheral blood stem cell transplantation that correlated with the lower functional capacity of HCMV-specific T cells, in particular with an increased proportion of HCMV-specific CD8 T cells that produced a single cytokine and a lower proportion of polyfunctional cells.