Signatures and Specificity of Tissue-Resident Lymphocytes Identified in Human Renal Peritumor and Tumor Tissue

Visual Abstract Significance Statement Tissue-resident memory T (TRM) cells are important for localized immune responses, but their phenotypic and functional diversity in human kidneys is poorly understood. In this study, CD4+ and CD8+ TRM and other resident lymphocytes from tumor- and nontumor-containing kidney tissue samples of 62 patients with nephrectomy were extensively analyzed. It was shown that intrarenal CD8+ TRM cells express an activated, proinflammatory phenotype and become more numerous with age. Within tumors, however, CD8+ TRM cells more frequent express markers of exhaustion and become functionally impaired in patients with metastasis. Multiple viral antigen specificities were also demonstrated for intrarenal CD8+ TRM. These and other observations from the study provide novel insights into the complex repertoire of human kidney–resident lymphocytes with relevance for renal cancers and transplants. Background Tissue-resident memory T (TRM) cells are known to be important for the first line of defense in mucosa-associated tissues. However, the composition, localization, effector function, and specificity of TRM cells in the human kidney and their relevance for renal pathology have not been investigated. Methods Lymphocytes derived from blood, renal peritumor samples, and tumor samples were phenotypically and functionally assessed by applying flow cytometry and highly advanced histology (multi-epitope ligand cartography) methods. Results CD69+CD103+CD8+ TRM cells in kidneys display an inflammatory profile reflected by enhanced IL-2, IL-17, and TNFα production, and their frequencies correlate with increasing age and kidney function. We further identified mucosa-associated invariant T and CD56dim and CD56bright natural killer cells likewise expressing CD69 and CD103, the latter significantly enriched in renal tumor tissues. CD8+ TRM cell frequencies were not elevated in kidney tumor tissue, but they coexpressed PD-1 and TOX and produced granzyme B. Tumor-derived CD8+ TRM cells from patients with metastases were functionally impaired. Both CD69+CD103−CD4+ and CD69+CD103−CD8+ TRM cells form distinct clusters in tumor tissues in proximity to antigen-presenting cells. Finally, EBV, CMV, BKV, and influenza antigen-specific CD8+ T cells were enriched in the effector memory T cell population in the kidney. Conclusions Our data provide an extensive overview of TRM cells’ phenotypes and functions in the human kidney for the first time, pointing toward their potential relevance in kidney transplantation and kidney disease.