Susana R. Marino

Characterization of two novel HLA‐DPB1 alleles: HLA‐DPB1*1069:01, and DPB1*1072:01 containing non‐synonymous nucleotide substitutions.

Spherotech (SPT) microparticles capture non‐specific binding materials present in test serum, and EDTA removes the so called” prozone effect”. This study presents a novel approach of combined SPT‐EDTA serum treatment prior to Luminex HLA antibody testing to remove high background, and prozone effect in a single step process, and compared the efficacy of SPT‐EDTA serum pre‐treatment with AdsorbOut (ADS) and Serum Cleaner (SC) to reduce background in solid phase immunoassays (SPI). A total of 21 serum samples with a history of elevated negative control (NC) values ≥500, and 20 samples with normal NC values were included to assess the potential adverse effects. A problem of high background was noted in 25% of our samples in SPI. We observed 80% effectiveness in reducing NC values p < 0.001). No adverse effect was noted on NC, positive control (PC) values, PC/NC ratios in the upfront use of SPT‐EDTA as compared to EDTA alone. Our data revealed that combined SPT‐EDTA treated sera is more effective than ADS, and SC in reducing high background in SPI. Taken together, SPT‐EDTA serum treatment prior to Luminex HLA Ab testing is cost‐effective, our laboratory saves nearly 30% of the annual total cost for Ab testing and improved test turnaround time by two business days.

We describe a unique ABO compatible and 9/10 HLA‐matched case of successful allogeneic hematopoietic cell transplantation (HCT) after effective desensitization of a strong anti‐HLA‐A24 donor‐specific antibody (DSA) with mean fluorescence intensity of approximately 18 000. Due to absence of a suitable matched unrelated donor the patient sibling was considered the best available donor, and it was decided to desensitize patient prior to transplant. The strength of HLA‐A24 DSA slowly decreased over the course of treatment, necessitating a total of 23 sessions of therapeutic plasma exchange in order to bring the DSA strength to undetectable levels, followed by a successful transplant. In summary, the outcome of this case shows effective application of desensitization treatment to remove strong DSA in HCT patients.