Furthermore, CD4 + T cells are fundamental to prevent HCMV reactivation in immunocompromised patients receiving solid organ allografts (Lim et al., 2020) or hematopoietic cell transplantation (HCT), while insufficient CD4 + T cell levels in transplant recipients are associated with recurrent HCMV reactivation, end-organ disease, and an increased likelihood of lethal infections (Einsele et al., 1993; Gabanti et al., 2015). Here, CD4 is linked to infection.