168-P: NOVEL B∗51:11N ASSOCIATION WITH THE A∗03:01-C∗07:02-DRB1∗04:02-DQB1∗03:02 HAPLOTYPE IN AN AFRICAN AMERICAN FAMILY

Abstract

Aim B∗51:11N is a common and well-documented null allele that results from a single cytosine insertion in exon 4. Laboratories must be able to identify this allele in those individuals carrying the A∗02:01-C∗15:02/13-DRB1∗04:02 haplotype. We recently found B∗51:11N allele associated with the A∗03:01-C∗07:02-DRB1∗04:02-DQB1∗03:02 haplotype in an Africa American family. Methods The mother (recipient) and the son (donor) were HLA typed by SSP (One Lambda, Olerup), rSSOP (Gen-Probe LifeCodes) and cytotoxicity methods. Post-transplant, HLA antibodies were identified by Luminex single antigen beads (SAB, One Lambda). Flow cytometry and CDC crossmatches were performed pre-transplant. Results The mother’s HLA typing was A3,-74; B51,-18; Cw2,-7; DR4,-18; DQ4,-8 by rSSOP and her son’s HLA typing was A3,-68; B44,-; Cw2,-7 by cytotoxicity and DR1,-4; DQ5,-8 by SSP. The mother received the kidney from her son in 2007 following negative crossmatches. Post-transplant monitoring revealed an anti-B51 antibody by Luminex SAB assay which triggered re-examination of the mother’s and son’s B-locus typing by high-resolution typing. Both individuals were found to possess theA∗03:01-B∗51:11N-C∗07:02-DRB1∗04:02- DQB1∗03:02 haplotype. Conclusions The A∗03:01-C∗07:02-DRB1∗04:04-DQB1∗03:02 haplotype is known to be associated with B51:01 or B∗51:11N. We describe a case of A∗03:01-C∗07:02-DRB1∗04:02-DQB1∗03:02 haplotype in an African American family associated with the B∗51:11N allele. This case emphasizes the continued importance of identifying null alleles in solid organ transplantation. In addition, this null allele-haplotype association should be kept in mind when accepting solid organ donors by means of virtual crossmatching.