COMPARISON OF SEROLOGICAL AND MOLECULAR TYPING FOR HLA-A AND HLA-B ONCORD-BLOOD LYMPHOCYTES

HLA class I typing by standard microcytotoxicity testing has been unsa tisfactory for 14.5% of 1644 cord blood samples, In this study, we eva luated the capacity of PCR-SSP in solving problems in HLA-A,B typing w ith serological methods. With this aim we have compared serology with PCR-SSP in 100 cord blood samples with doubtful or unreliable HLA-A,B typing. PCR-SSP was successful in amplifying RLA-A,B alleles in all 10 0 cord blood samples. Forty-six typings gave discrepant results with t he 2 methods (serology and PCR-SSP). Typings were considered discrepan t also in the case of inability to define a split. For 19 specimens, n o serological conclusion was drawn due to high mortality of the cell s uspension, while PCR-SSP allowed the definition of a clear typing. In 6 cases it was necessary to infer information from serology to define the current typing. Finally, in 3 other cases it was impossible to exc lude or attribute the antigen/allele B67 or B4802. PCR-SSP for HLA-A,B can improve the overall reliability of HLA-A,B typing requiring a sma ll amount of blood although, with the set of sequence specific primers adopted, a number of alleles are still poorly defined.