Compromised long‐lived memory CD8+ T cells are associated with reduced IL‐7 responsiveness in HIV‐infected immunological nonresponders

Immune deficiency is one of the hallmarks of HIV infection and a major cause of adverse outcomes in people living with HIV (PLWH). Long‐lived memory CD8+ T cells (LLMCs) are essential executors of long‐term protective immunity; however, the generation and maintenance of LLMCs during chronic HIV infection are not well understood. In the present study, we analyzed circulating LLMCs in healthy controls (HCs) and PLWH with different disease statuses, including treatment naïve patients (TNs), complete responders (CRs), and immunological nonresponders (INRs). We found that both TNs and INRs showed severely compromised LLMCs compared with HCs and CRs, respectively. The decrease of LLMCs in TNs correlated positively with the reduction of their precursors, namely memory precursor effector T cells (MPECs), which might be associated with elevated pro‐inflammatory cytokines. Strikingly, INRs showed an accumulation of MPECs, which exhibited diminished responsiveness to interleukin 7 (IL‐7), thereby indicating abrogated differentiation into LLMCs. Moreover, in vitro studies showed that treatment with dexamethasone could improve the IL7‐phosphorylated (p)‐signal transducer and activator of transcription (STAT5) response by upregulating the expression of the interleukin 7 receptor (IL‐7Rα) on MPECs in INRs. These findings provide insights that will encourage the development of novel therapeutics to improve immune function in PLWH. The loss of LLMCs is mainly attributed to poor MPEC maintenance in TNs, but is caused by differentiation failure of MPECs in INRs. IP‐10 serves as a determinant factor for MPEC survival in TNs, while impaired IL‐7 responsiveness of MPECs accounts for the differential defects in INRs.