CD4 and infection: Taking this into account, it was found that if patients were stratified into 3 groups: (i) those that could self-resolve infection, (ii) those that responded to treatment, and (iii) those that had recurrent infections and end-organ disease, this third group of patients had high levels of HCMV-specific CD8+ T cells, with persistently low levels of total CD4+ T cells and <1 cell/μl of blood of HCMV-specific CD4+ T cells 6 months post-transplant (Gabanti et al., 2015).