Higher levels of IL-6, CD4 turnover and Treg frequency are already present before cART in HIV-infected subjects with later low CD4 recovery.

Immunological characterization of HIV-infected subjects with low CD4-recovery (LR-subjects) has been extensively performed after a variable period of combined antiretroviral therapy (cART). We now explore immunological alterations present before the cART onset. In a case-control study, we selected pre-cART samples of HIV-subjects with and without low CD4-recovery after cART (n = 21 per group). CD4 T-cell activation, senescence and exhaustion related markers were not found specifically altered before cART initiation. On the other hand, we found that LR-subjects before cART already showed increased levels of IL6 (p = 0.009) and increased frequencies of Ki67+CD4+ T-cells (p = 0.026), CD45RA-CD27+CD4+ T-cells (p = 0.008) and Treg (p = 0.001), as well as increased expression of CD95 and CD127 on CD4 T-cells (p = 0.016; p = 0.032, respectively). These parameters characterize the immunological damage in LR-subjects before the cART onset and could be associated to the mechanisms hindering the subsequent CD4 recovery.