HLA Class I typing of volunteers for a bone marrow registry: QC analysis by DNA‐based methodology identifies serological typing discrepancies in the assignment of HLA‐A and B antigens

Abstract

Until recently, the majority of newly recruited volunteer donors were typed for HLA-A and -B by serology onto the National Marrow Donor Program Registry. Quality control of this serological typing performed by contracted laboratories was carried out by retesting approximately 1% of each laboratory's test volume utilizing DNA-based techniques (SSOP). The criteria used for selection included samples presumed to be homozygotes, samples with split antigen specificities and samples with antigens considered to be difficult to define. Out of 1983 samples analyzed, 156 HLA-A (3.9%) and 265 HLA-B (6.7%) locus discrepancies were identified. Review of these discrepancies by both the serological and QC laboratory revealed that the majority of discrepancies were due to errors in serological typing. Serological discrepancies were categorized as follows: blank antigens identified (36.8%) and misassignments (63.2%). Misassignments were defined as either the incorrect assignment of antigens within a group ("wrong split"), or a complete misassignment. Antigens reported as blanks most frequently belonged to the A19 and A28 groups and to the B70, 46 and 40 groups. The most frequent misassignments within groups were the A19 and A10 groups, and the B40 and B15 groups. Other HLA-A misassignments included A2 vs A28 or A2 vs A69, while other HLA-B misassignments included B35 and B70. This QC analysis showed that serological typing of class I antigens for the purposes of NMDP registry typing is prone to a significant error rate. Careful evaluation and selection of contracted laboratories by the NMDP suggests methodological limitations rather than poor performance as the main cause of these observations.

Transplant Nephrectomy: Histologic Findings - A Single Center Study

“…HLA-A, B, Cw, and DR typing were performed on each donor and recipient prior to transplantation, using serologic and DNA-based typing as previously described [13,14]. In addition, HLA-DQ and HLA-DP typing were performed on selected donors and recipients when necessary and when donor material was available, to define anti-DQ and anti-DP DSA.…”

HLA DR and DQ alleles and haplotypes associated with clinical response to glatiramer acetate in multiple sclerosis

“…Samples from collaborating centers were sent via overnight delivery at room temperature and processed immediately upon arrival. Intermediate HLA typing for DR and DQ alleles was performed at the Tissue Transplantation Laboratory at the University of Pennsylvania using DNA-based technology as described (Gourley et al, 2002). Briefly, genomic DNA was purified from PBMC using the QIAamp blood kit (QIAGEN Inc. Valencia, CA).…”

HLA-A amino acid polymorphism and delayed kidney allograft function

“…We resolved low-resolution (serological or antigen level) disparities by converting the DNA-based typing to its lower-level serologic equivalent. We described all of these procedures in a previous article (14,24).…”

“…Low-resolution typing was performed by DNA-based methods for HLA-A and -B on all donors and recipients to better define antigen splits and minimize errors resulting from antigens that are difficult to type serologically (24). High-resolution HLA-A, -B, and -DRB1 typing was performed only in donor-recipient pairs that had fewer than two mismatches at their respective HLA loci by low resolution typing.…”