Historically HLA typing of deceased donors was performed using serological or DNA-based methods. On 6/1/11, the Organ Procurement and Transplantation Network (OPTN) implemented a new policy requiring DNA-based methods for HLA typing of deceased kidney, kidney-pancreas and pancreas donors because serological typing methods have higher error rates and are more likely to include broad HLA specificities; both of these limitations affect the accuracy of virtual crossmatches. On behalf of the OPTN Histocompatibility Committee, we report here the early results of HLA typing during the first year after implementation of this policy.

Methods: All results are based on OPTN data as of 10/19/2012. Deceased donor HLA types were tabulated for kidney, kidney-pancreas, or pancreas match runs that culminated in an offer to at least one candidate. Match runs performed without a donor HLA type were excluded. The frequencies of HLA types were compared for match runs performed in 6-month intervals one year before and after DNA-based typing was required. The following HLA types were defined as broad specificities: A9, 10, 19, and 28; B5, 12, 14, 15, 16, 17, 21, 22, 40, and 70; C3, DR2, 3, 5, and 6; and DQ1and 3.

Results: In each 6 month period, the percentage of donors with broad antigens listed in their HLA types was significantly lower than that of the prior 6 months (Table 1). During the 6 months prior implementation of the new policy the percentage of donors with at least one broad antigen decreased by 27%. After implementation, the number decreased by 41% during the first 6 months and an additional 38% in the next 6 months. C3 was the most commonly reported broad antigen. DQ3 and B14 were also frequently reported.

Conclusions: Use of DNA-based typing has dramatically reduced reporting of broad specificities for deceased donors. This improvement in HLA typing resolution is expected to translate into more accurate virtual crossmatches and increase the efficiency of organ allocation.

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