HLA-A*02010102L: a laborious assignment.
ABSTRACT In the present report we describe the laborious identification of the A*02010102L allele found in three healthy individuals of a French family who have shown a reduced A2 antigen expression using serological tests since the 1980s. PCR-SSP typing showed a classical A*0201 allele. Sequencing of exons 2, 3 and 4 confirmed this assignment. Sequencing of the whole gene (promoter, introns and exons 1-8) revealed one single point mutation (T to C) at position -101 in the enhancer B element region compared to the A*02010101 allele. This single mutation appears to be related to the reduced expression of the A2 antigen. This allele segregates with the haplotype Cw*12, B44, DR7, DQ2, which is different to the one described earlier.
- SourceAvailable from: Carlheinz Rudolf MüllerTissue Antigens 04/2010; 75(4):291-455. · 2.93 Impact Factor
- New Advances in Stem Cell Transplantation, 02/2012; , ISBN: 978-953-51-0013-3
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ABSTRACT: Matching of human leukocyte antigen (HLA) alleles between donors and recipients plays a major role in hematopoietic stem cell transplantation (HSCT). Null or questionably expressed HLA allelic variants are a major issue in HLA matching, because the aberrant expression of such alleles can have a major impact on the outcome of HSCT and/or its complications such as graft-versus-host disease. The goal of this study was to investigate the potential of a recently developed cytokine-induced secretion assay to differentiate the expression levels of HLA-A*32:11Q (questionable) into a null (N) or low (L) expression variant. An amino acid mutation at position 164 of HLA-A*32:11Q disrupts the disulfide bridge in the α2 domain. HLA-A*32:11Q is not detectable by standard microlymphocytotoxicity assay. To this end, we cloned soluble HLA-A*32:11Q and a reference allele (HLA-A*32:01) into expression vectors and transfected/transduced HEK293 and K562 cells. Allele-expressing K562 cells were simultaneously transfected/transduced with a β2-microglobulin (B2M)-encoding vector to ensure the intact HLA structure with B2M. After treatment with proinflammatory cytokines, secreted soluble HLA molecules were determined by enzyme-linked immunosorbent assay in the supernatant and intracellular accumulation of the recombinant proteins by flow cytometry. HLA-A*32:11Q was nearly undetectable in untreated transfectants. Cytokine treatment increased the secretion of HLA-A*32:11Q to detectable levels and resulted in intracellular accumulation of the allele. There was no difference in mRNA transcription between the A*32 alleles. On the basis of these results, we recommend reclassification of HLA-A*32:11Q as a low expression (L) variant.Tissue Antigens 05/2012; 79(5):340-50. · 2.93 Impact Factor