P140 Successful kidney transplantation of a highly sensitized patient (HSP) with allele-specific antibody (ASA) against DR52 after several rejected national offers: A case report

Abstract

The existence of pre-formed donor Specific antibodies (DSA) is considered a contraindication for transplantation. HSPs with cPRA ⩾95% account for about 20% of the waitlist but receive ⩽1% of accessible donor organs. National HSP programs improve the chances of finding donors for these difficult to-match patients but the majority of HSP declined offers are due to ASA not detected by virtual XM. We present a 54 year old, Caucasian, male, and ABO group A, with ESRD secondary to diabetes mellitus. The patient had a deceased donor (DD) kidney in 1993 that was lost due to chronic rejection and he resumed dialysis in 2004. In October 2006, the patient presented with de-novo class I and class II HLA antibodies. By 2014 the patient’s cPRA was 98% and was listed on the national transplant registry for HSP. Within a period of a year, the patient received 3 HSP offers but were all rejected by the transplant team due to the existence of a strong ASA to HLA DR52. On Oct21 2015, the patient received a virtually negative XM HSP donor offer that was followed with a final negative T cell and weak positive B cells flow XM. The patient was successfully transplanted and in the early outcome he achieved a base line serum creatinine of 126 on day 19 post-surgery and was discharged on Nov9, 2015. On high resolution typing, this patient carries a DRB3∗02:02 allele and has high titre HLA antibodies against DRB3∗01:01 and DRB3∗03:01. We hypothesized that a donor carrying HLA-DRB3∗01:01 will be incompatible to this patient due to the presence of AS DSA. To test this hypothesis, we performed a surrogate XM with a donor that has similar typing to patient except for DRB3∗01:01. This resulted in a T cell negative and B cell positive flow XM. On the other hand, when we used a surrogate donor with DRB3∗02:02 allele, the T and B cell XMs were negative. HSP programs have positively impacted the transplantation of the HSP. Since 2004, this patient has had positive B cell flow XMs against more than 30 DDs. Kidney allocation programs as in HSP should include high resolution typing of donors’ HLA and the complete antibody panel screening for the transplant candidate to allow for a safe allocation. HSP programs should flag ASAs to avoid unnecessary offers to patients who are HS and show HLA self reactivity. More data is needed to understand the impact of ASAs on HSP.