[A comparative study of serological, monoclonal antibody and DNA typing in identifying HLA-A]

A double-blind study was carried out to evaluate the accuracy and reliability of PCR-SSP assay in comparison with serology and monoclonal antibody(mAb) typing in identifying HLA-A alleles in Southern Chinese population.

A total of 296 samples were entered into the study, including 143 unrelated kidney donors and 153 recipients. HLA-A typing was performed by standard two-stage microlymphocytotoxicity assay, one-step mAb typing and PCR-SSP typing.

All samples were successfully typed by PCR-SSP. Reproducibility was 100%. The results were confirmed by a panel of standard DNAs and a double-blind typing of UCLA tissue typing lab. However, mAb typing(for Asian) in 149 samples showed 2.7% misassignment including 1 antigen being incorrectly interperted and 3 of 26 "blanks" turning out to be definable alleles by DNA typing. Serological discrepancy rate was 15.6% in 147 samples consisting of 8 antigens being incorrectly interpreted, 13 "blanks" turning out to be definable alleles and 2 heterozygotes turning out to be homozygotes by DNA typing.

HLA-A typing by PCR-SSP proved to be a rapid and accurate technique, suitable for clinical application with a greater precision than serology. In large scale screening, mAb typing (for Asian) is recommended. Antigens of "blanks" or "difficult" by serology or mAb typing should be retyped by DNA typing.