185-P: DEDUCTION OF MISMATCHED DONOR HLA FROM URINE SAMPLES OF KIDNEY TRANSPLANTED RECIPIENTS

Aim We previously demonstrated that mismatched donor human leukocyte antigen (HLA) could be deduced from HLA typing of fresh or archived paraffin-embedded renal allograft tissue (Clin. Transplant 2010;24:E178-81; Histopathology, In press), thereby allowing the detection of donor-specific antibodies. In the present study, we investigated the detection of mismatched donor HLA using the kidney recipient’s urine sample. Methods Forty-three urine samples from kidney transplant recipients with known HLA in both donor and recipient were studied. Each 40 ml sample was centrifuged at 2500 rpm for 20 minutes. The supernatant was discarded, the sediment washed with 1X PBS, after which the mixture was centrifuged at 2500 rpm for 20 minutes. DNA extraction was performed on samples with sufficient cell sediment through visual inspection. Genomic DNA was extracted using EZmag Genomic DNA Whole Blood Kit (Texas BioGene Inc., Taiwan). HLA Class I and II antigens were typed by PCR-SSP. Results 62.8% (27/43) of urine samples showed sufficient sediment. Extracted DNA concentration was in the range of 1700-2600 η g with purity (A260/A280) of 1.66-1.98. 41.9% (18/43) had sufficient DNA for HLA testing. One case had zero mismatch between donor and recipient. Of 17 mismatched cases, the HLA typing of recipients was achieved in all subjects. Mismatched donor HLA phenotypes were detected completely in 3 of the 17 subjects (17.6%), with the samples collected on Day 5, 14, and 1268 after kidney transplantation. Mismatched donor HLA data was partially detected in another 6 subjects (35.3%). Conclusions Detection of mismatched donor HLA from the urine of kidney transplant recipients has an overall success rate of 7% (3/42). The presence of sufficient donor-derived substrate for HLA typing appears critical. Further investigations are warranted to explore ways to improve the performance of this non-invasive technique for the detection of mismatched donor HLA in kidney transplant recipients with unknown donor HLA phenotype.