COMPARISON OF HLA-A ANTIGEN TYPING BY SEROLOGY WITH 2 POLYMERASE CHAIN-REACTION BASED DNA TYPING METHODS - IMPLICATIONS FOR PROFICIENCY TESTING

Serology has been routinely used for class I HLA typing for the select ion of donors for allotransplantation. However, serology is not adequa te for the assignment of all class I specificities especially when tes ting non-Caucasians subjects and it is necessary to adopt new strategi es for routine testing. At the present time the extent of incorrect se rologic HLA-A assignments in clinical testing is nor known. The polyme rase chain reaction (PCR) based techniques have become useful standard clinical typing methods of HLA class II alleles but most laboratories still use serology for class I typing. In this report we have compare d two PCR based techniques, PCR amplification with sequence-specific p rimers (PCR-SSP) and PCR amplification and subsequent hybridization wi th sequence-specific oligonucleotide probes (PCR-SSOP), for the assign ment of HLA-A specificities in 56 blood samples from patients and fami lies serologically typed for HLA-A. This side-by-side comparison of PC R methods showed 100% correlation between them. However, serology show ed 7.1% misassignments and, in an additional panel of 19 cells where s erology produced equivocal results, the PCR-SSP and SSOP methods ident ified the correct HLA-A specificity. Our results emphasize the need to complement routine serologic testing of HLA specificities with a smal l number of primers designed to test HLA-A34, A36, A43, A66, A74 and A 80, that are not detected with high precision by serology. We conclude d that the PCR-SSP and -SSOP methods can be used in routine HLA-A typi ng of patients and donors for transplantation with a greater precision than serology.