Regarding the thirty control subjects with HCMV remote infection, six (17%) showed a HCMV-specific CD4+ T-cell response against one peptide pool, 12 (40%) and nine (30%) against two and three peptides pool, respectively, and nobody against four peptide pools, while three (13%) showed no HCMV-specific CD4+ T-cell response (Figure 2A). Here, CD4 is linked to infection.