Causes of Positive Pretransplant Crossmatches in the Absence of Donor-Specific Anti-Human Leukocyte Antigen Antibodies: A Single-Center Experience
2021; 41(4): 429-435
Korean J Clin Pathol 1999; 19(2): 239-245
Published online April 1, 1999
Copyright © Korean Society for Laboratory Medicine.
Background :Using the classical serological methods, the HLA-Cw typing resulted in a high frequency of Cw blank because of the lack of suitable antisera coupled with low cell surface expression. Recent data on association between graft-versus-host disease and serologically undetectable HLA-Cw mismatches in bone marrow transplantation (BMT) facilitate the investigations into the biological role of HLA-Cw and more reliable HLA-Cw typing. Method :We performed the HLA-Cw DNA typing using PCR-SSP technique with sequence-specific primers of 22 pairs in 150 Koreans (79 organ transplant recipients, 71 healthy potential donors). These results were compared with those of serological HLA-Cw typing, which had been performed by complement-dependent microlymphocytotoxicity technique using Terasaki Tissue typing tray. Result :Comparison between serological and PCR-SSP typing revealed a discrepancy rate of 24.0% (36/150). The majority of total discrepancies (29/36, 80.6%) were due to antigens that were not detected serologically and these antigens consisted of mainly Cw?12 and Cw?15. In five cases, no Cw allele was detected by DNA typing, whereas serological typing showed antigens and different antigen assignments between two methods were found in three cases. Of 66 individuals typed serologically with one blank, 66.6% (44 cases) were confirmed to be homozygous, whereas an additional Cw allele was found in remaining 22 cases using the PCR-SSP technique. In the case of the serologically undetectable HLA-Cw blank antigens, the gene frequencies of Cw? 12 and Cw?15 were 6.4% and 2.8%, respectively. Conclusion :These results indicated that serological typing is insufficient for accurate HLA-Cw typing. DNA typing using PCR-SSP technique appears a reliable and practical method for accurate HLA-Cw typing which can contribute to the evaluation of the biological role of the HLA-Cw in transplantation.
Keywords: HLA-Cw, Serological typing, PCR-SSP, Transplantation