Single-cell TCR profiling of CSF and blood cells of PWH reveals persistent and shared infected T cell clones across tissue compartments even after ART

The brain is a site of persistent infected cells during HIV infection. However, the dynamics of central nervous system (CNS) infection and T cell trafficking in people living with HIV (PWH) are incompletely understood. We profiled the single cell T cell repertoire and host transcriptome from paired blood and cerebrospinal fluid (CSF) from PWH and uninfected controls. We detected HIV RNA-producing cells in 8/11 (72.7 %) CSF samples and 6/11 (54.5 %) blood samples, with a higher frequency of infected single CD4 T cells in CSF than in blood. Infected CSF T cells displayed a unique transcriptional profile compared to uninfected CSF T cells. Most infected T cell clones were not shared across tissue; however, in a subset of participants we detected identical T cell clones that were infected in both CSF and blood. Longitudinally following one PWH before and at three time points after initiating ART, we found infected T cell clones that persisted after ART initiation, in both CSF and blood, including a T cell clone that expanded in the CSF several months after ART initiation. Our findings suggest that infected T cells traffic to the CNS where they undergo clonal expansion despite ART, contributing to the CNS reservoir.