Mapping the Lineage Relationship between CXCR5+ and CXCR5− CD4+ T Cells in HIV-Infected Human Lymph Nodes

Abstract

Summary: CXCR5 is a key marker of follicular helper T (TFH) cells. Using primary lymph nodes (LNs) from HIV-infected patients, we identified a population of CXCR5− CD4+ T cells with TFH-cell-like features. This CXCR5− subset becomes expanded in severe HIV infection and is characterized by the upregulation of activation markers and high PD-1 and ICOS surface expression. Integrated analyses on the phenotypic heterogeneity, functional capacity, T cell receptor (TCR) repertoire, transcriptional profile, and epigenetic state of CXCR5−PD-1+ICOS+ T cells revealed a shared clonal relationship with TFH cells. CXCR5−PD-1+ICOS+ T cells retained a poised state for CXCR5 expression and exhibited a migratory transcriptional program. TCR sequence overlap revealed a contribution of LN-derived CXCR5−PD-1+ICOS+ T cells to circulating CXCR5− CD4+ T cells with B cell help function. These data link LN pathology to circulating T cells and expand the current understanding on the diversity of T cells that regulate B cell responses during chronic inflammation. : Follicular helper T (TFH) cells are critical for antibody production. Del Alcazar et al. showed that TFH cells can lose their characteristic chemokine receptor, giving rise to migratory populations of CXCR5− T cells that retain B cell help function and are poised for CXCR5 expression. Keywords: human, mass cytometry, HIV, infection, chronic inflammation, lymph node, follicular helper T cells, T-bet+ B cells, migration