Heterogeneity and Clonality of Kidney-infiltrating T cells in Murine Lupus Nephritis.

Purpose:We previously found that kidney-infiltrating T cells (KITs) in murine lupus nephritis (LN) resembled dysfunctional T cells that infiltrate tumors. This unexpected finding raised the question of how to reconcile the “exhausted” phenotype of KITs with ongoing tissue destruction in LN. Methods: we performed scRNA-seq and TCR-seq of KITs in murine lupus models using 10X Genomics Chromium system . Results: We found that CD8 KITs exist first in a transitional state, before clonally expanding and evolving toward exhaustion. On the other hand, CD4 KITs did not fit into current differentiation paradigms, but included both hypoxic and cytotoxic subsets with a pervasive exhaustion signature. Thus, autoimmune nephritis is unlike acute pathogen immunity; rather the kidney microenvironment suppresses T cells by progressively inducing exhausted states. Our findings suggest that lupus nephritis, a chronic condition, results from slow evolution of damage caused by dysfunctional T cells and their precursors on the way to exhaustion. These findings have implications for both autoimmunity and tumor immunology. mRNA profiles of CD4 and CD8 T cells from spleen and kidney of murnine lupus nephritis models were generated in triplicate by sequencing using Illumina NextSeq 500