<scp>HLA</scp>‐Typing of Donor‐Origin Cells Enriched From Urine Cell Culture of Kidney Transplanted Recipients

The incomplete or lack of histocompatibility information constitutes a barrier for the early detection and management of de novo donor-specific antibodies (DSA). To improve the quantity and quality of DNA materials for HLA typing, we developed a non-invasive culture-based method, using DNA extracted from enriched donor-derived kidney stem cells (DKSC) selectively cultured from the urine of kidney transplant receipients (KTR) to allow high-resolution typing by next-generation sequencing. This prospective proof-of-concept study evaluated the feasibility and performance of this approach. DKSC were enriched from the urine of 60 KTRs. DNA extracted from culture-enriched DKSC showed significantly higher concentration and better quality than unbound cells, and with identical short tandem repeat (STR) and 100% concordance compared to that obtained from peripheral blood. Our results suggest that cultured-enriched DKSC are non-invasive and useful for determining HLA and other genes for KTRs where donor information is limited or lacking.