The use of gamma interferon (IF) in prenatal diagnosis, prenatal paternity testing and genetic studies: Increased expression of HLA-A,B,C locus antigens on amniotic cells and induction of HLA-DR expression on fibroblasts

HLA typing of cultured amniotic cells or fibroblasts can be used for prenatal diagnosis of monogenetic diseases such as 21-hydroxylase or C4 deficiencies, for prenatal establishment of paternity, to establish the true HLA genotype of patients engrafted with allogeneic lymphocytes or to identify marker antigens for immunodeficiency patients receiving fetal liver grafts. In our experience, however, the determination of HLA allotypes has been hindered in many instances by weak expression of most HLA-B and -C antigens on these cultured cells. In a few cases, the polymorphism of HLA-A and B alone has also been insufficient to establish the true genetic source of the cells. Since gamma interferon (If) has been shown to enhance HLA antigen expression on a variety of cell types, we treated cultured amniotic cells and fibroblasts with partially purified If prior to HLA typing. In several cases, if treatment allowed previously undetected B or C locus antigens to be determined by microcytotoxicity with alloantisera. All 3 fibroblasts strains tested also showed the induction of DR antigens, detected by a battery of monoclonal antisera, with similar kinetics. Non-HLA antigens such as T-cell differentiation antigens were not induced and a monoclonal anti If antibody abrogated the DR antigen induction. These results suggested that gamma If would be useful in both clinical and genetic studies utilizing amniotic cells or fibroblasts.