OR52 HLA typing from a deceased donor who received hematopoietic stem cell transplant

Here we present a case of challenging typing for a deceased donor who is also hematopoietic stem cell (HSC) transplant recipient. A local deceased donor (DD) was typed with SSP method from peripheral blood sample as A2; B44, 62; Cw9,16; DR4,7; DQ2,7; DQA1∗02, 03; DPB1∗04:02, 11:01; DPA1∗01, 02. After typing was reported, it was immediately found out DD received HSC transplant from an unrelated donor in 2001 at another center. DD has full engraftment on death so HLA typing based on peripheral blood sample is likely the typing for her HSC donor. Typing for DD before HSC was found to be: A2; B44, 62; CW5, 9; DR4,7; DQ7,9, while her HSC donor is A2; B44, 62; Cw9,16; DR4,7; DQ2,7. DQA1∗ and DP typing were not performed in 2001 and no stored DNA can be found. There are two mismatched antigen on HLA-CW and -DQ. This confirmed that initial typing results for DD in fact were typing for her HSC donor, not typing for the kidneys. One kidney was exported to a patient with anti-HLA DP antibodies at another center. The receiving center asked to determine HLA-DP phenotype for DD. Without other source of somatic DNA, a piece of blood vessel from harvested kidney was used to extra DNA for DPB1∗ SSP typing. The blood vessel was contaminated with blood from her HSC donor. It was found that there are four DPB1 antigens: DPB1∗04:02, 11:01, and DPB1∗01:01, 04:01. HSC donor typing is the typing got from blood sample of DD: DPB1∗04:02, 11:01. So DPB1∗01:01, 0401 were deduced as the presumptive typing for this deceased donor. Fortunately there is no anti-HLA-DP DSA for the designated recipient. In summary, a deceased donor was mistakenly typed based on improper source of specimen. Recipients of HSC transplant rarely become deceased organ donors. However, many patients received HLA-DP mismatched unrelated HSC transplant because usually HLA-DP was not matched. Anti-HLA-DP antibodies are found in lots of patients waiting for kidney transplant. This case highlights the importance of communication with deceased donor team, and proper sample collection to achieve accurate deceased donor typing and excellent virtual cross match.