In general, the repertoire of proviral sequences found at the different CD4+ T-cell subsets showed a mixed genetic population in all patients, possibly indicating cross-infection events between subsets and/or migration events of proviral quasispecies as a result of cellular differentiation from one functional phenotype to another, as previously described for resting versus activated CD4+ T-cell subsets [54, 55]. Here, CD4 is linked to infection.