Retrospective tissue typing of the kidney donor from recipient urine

Given that it is possible to extract DNA from the urine of kidney transplant donors and recipients we studied whether the donor HLA type can be determined from recipient urine. This would be useful especially when there is limited information on donors or when the transplant was performed long ago when tissue typing was less precise. We extracted and purified DNA from fresh urine and used the standard HLA class I and class II PCR-SSP assays comparing the findings to those obtained from peripheral blood of donor and recipient HLA types. Using the urine of 31 renal transplant recipients we assayed for the 140 known mismatches, and all were detected in technically successful assays with only a single false positive. This shows that urine samples of transplant recipients can be used to generate historical HLA typing information of the donor thereby aiding post-transplant immunologic monitoring.