Public determinants of HLA indicated by pregnancy antibodies.

A tentative table of public specificities in the HLA-A and -B loci is provided. It is based on an all-inclusive survey of placenta extracts from 50,000 pregnancies. We postulate that most of the specificities found are directed against public epitopes. In support of this postulate are the facts that certain combinations occur very frequently, monoclonal antibodies have been made to some of the epitopes, and some have already been established by absorption experiments as being a single specificity. The immunogenicity score for each private and public specificity was computed by taking into account the chance of immunization. It was shown that immunogenicity can vary by factors of more than ten between different specificities. Significantly, immunogenicity of the public epitopes was just as high as against the private ones. This indicates that the public epitopes should be considered as independent, separate antigens in transplantation. Establishment of a table of public specificities and the recognition of each by international nomenclature would be the first step in evaluating public epitopes for transplantation matching.