CD4 and Opportunistic infection: Fernández-Ruiz and colleagues reported that low TBNK cell counts in kidney transplant recipients predicted post-transplant opportunistic infection, and found that CD8+ T cells less than 100 cells/μl and CD4+ T cells less than 50 cells/μl at month 1 were the most valuable predictive parameters for non-ATG and ATG groups, respectively [2].