Intestinal Tissue-Resident Memory T Cells and HIV-1 Persistence During Antiretroviral Therapy

Overview

The study aims to better characterize intestinal tissue-resident memory T cells (TRM) in people living with HIV-1 receiving suppressive antiretroviral therapy (ART). TRM cells are key components of tissue immunity and may contribute to HIV-1 persistence within the intestinal mucosa, a major viral reservoir. The phenotypic, transcriptomic, and functional characteristics of intestinal CD4+ and CD8+ TRM cells, their susceptibility to HIV-1 infection, and their potential role as viral reservoirs will be investigated. Blood samples and additional colonic biopsies obtained during routine clinically indicated colonoscopy will be collected from HIV-1-infected participants and HIV-seronegative controls.

Tissue-resident memory T lymphocytes (TRM) are a specialized population of memory T cells that reside permanently within tissues and play a central role in local immune defense. In HIV-1 infection, the intestinal mucosa represents a major site of viral replication, immune dysfunction, and long-term viral persistence despite effective antiretroviral therapy (ART). Intestinal CD4+ T cells are highly susceptible to HIV-1 infection and undergo profound depletion early during infection, while incomplete immune restoration persists under ART. Emerging evidence suggests that intestinal TRM CD4+ cells may be particularly susceptible to HIV-1 infection and may contribute to the maintenance of viral reservoirs because of their long lifespan and tissue retention properties. In parallel, TRM CD8+ cells may participate in local antiviral immune responses, although their functions may be impaired in the chronic inflammatory environment associated with HIV infection. The objectives of this physiopathological study are to improve understanding of the mechanisms involved in defective restoration of intestinal TRM populations during suppressive ART and to evaluate the contribution of TRM CD4+ cells to HIV-1 persistence. Exploratory objectives include the phenotypic, transcriptomic, and functional characterization of intestinal TRM CD4+ and CD8+ cells; assessment of the susceptibility of intestinal TRM CD4+ cells to HIV-1 infection; evaluation of their role as viral reservoirs, including intact proviruses; and investigation of mechanisms regulating tissue retention and recirculation of ex-TRM cells in the intestinal mucosa. This is a monocentric interventional physiopathological study with minimal risks and constraints (RIPH2). The study will enroll 20 people living with HIV-1 receiving suppressive ART and 10 HIV-seronegative controls matched for age and sex. Participants will be recruited among individuals undergoing routine colonoscopy, particularly for colorectal cancer screening indications. Study procedures consist of additional colonic mucosal biopsies collected during the clinically indicated colonoscopy and blood sampling performed on the day of the procedure.