Landscape of gut mucosal immune cells showed gap of follicular or memory B cells into plasma cells in immunological non‐responders

Abstract Background The gut is an important site for human immunodeficiency virus (HIV) infection and immune responses. The role of gut mucosal immune cells in immune restoration in patients infected with HIV undergoing antiretroviral therapy remains unclear. Methods Ileocytes, including 54 475 immune cells, were obtained from colonoscopic biopsies of five HIV‐negative controls, nine immunological responders (IRs), and three immunological non‐responders (INRs) and were analyzed using single‐cell RNA sequencing. Immunohistochemical assays were performed for validation. The 16S rRNA gene was amplified using PCR in faecal samples to analyze faecal microbiota. Flow cytometry was used to analyze CD4+ T‐cell counts and the activation of T cells. Results This study presents a global transcriptomic profile of the gut mucosal immune cells in patients infected with HIV. Compared with the IRs, the INRs exhibited a lower proportion of gut plasma cells, especially the IGKC + IgA + plasma cell subpopulation. IGKC + IgA + plasma cells were negatively associated with enriched f. Prevotellaceae the INRs and negatively correlated with the overactivation of T cells, but they were positively correlated with CD4 + T‐cell counts. The INRs exhibited a higher proportion of B cells than the IRs. Follicular and memory B cells were significantly higher in the INRs. Reduced potential was observed in the differentiation of follicular or memory B cells into gut plasma cells in INRs. In addition, the receptor‐ligand pairs CD74_MIF and CD74_COPA of memory B/ follicular helper T cells were significantly reduced in the INRs, which may hinder the differentiation of memory and follicular B cells into plasma cells. Conclusions Our study shows that plasma cells are dysregulated in INRs and provides an extensive resource for deciphering the immune pathogenesis of HIV in INRs. Key points An investigation was carried out at the single‐cell‐level to analyze gut mucosal immune cells alterations in PLWH after ART. B cells were significantly increased and plasma cells were significantly decreased in the INRs compared to the IRs and NCs. There are gaps in the transition from gut follicular or memory B cellsinto plasma cells in INRs.