Immune responses driven by protective human leukocyte antigen alleles from long-term nonprogressors are associated with low HIV reservoir in central memory CD4 T cells.

Background: The stable immune control of human immunodeficiency virus (HIV) in long-term nonprogressors (LTNPs) with protective human leukocyte antigen (HLA) alleles raises the question of whether and how these alleles influence the immune distribution of the HIV reservoirs.

Methods: Cell-associated HIV-DNA levels were quantified in blood sorted resting CD4 T-cell subsets from 8 LTNPs with and 10 without HLA-B*27 or HLA-B*57 alleles (HLA-B27/B57).

Results: A remarkably lower infection level of central memory CD4 T cells (T(CM)) was an exclusive feature that distinguished the HLA-B27/B57 HIV reservoirs from the other ones. In LTNPs, T(CM) protection was correlated with preservation of T(CM) counts, which correlated positively with the magnitude of HIV Gag-specific CD8 T cells. In HLA-B27/B57 LTNPs, a lower activation level of their memory CD4 T cells was associated with lower amounts of cell HIV-DNA in each resting memory CD4 subset and were also associated with higher ratios of HIV Gag-specific CD8 T cells per infected resting CD4 T cell (effector/target [E/T]). As a result, HLA-B27/B57 E/T ratios were negatively correlated with the contribution of memory CD4 T-cell subsets to the total HIV reservoirs.

Conclusions: The potent antiviral immunity governed by the protective HLA-B27/B57 alleles, by limiting T(CM) infection and pool exhaustion, are associated with a reduced T(CM) contribution to the HIV reservoir.