MATERNAL CELLS IN CHORIONIC VILLI FROM PLACENTAE OF NORMAL AND ABNORMAL HUMAN PREGNANCIES

PROBLEM: We asked if activated macrophages and CD4 positive T lymphocy tes in placental chorionic villi with villitis were of maternal or fet al origin. METHOD: We employed a double antibody immunocytochemical te chnique on placental sections from three normal and four abnormal preg nancies with small-for-gestational-age infants. All studied placentae were mismatched for the maternal-fetal HLA-DRw 52 antigen. Areas of im munopathology were identified by using a monoclonal antibody to a mono morphic determinant on HLA-DR, and the origin of immunological cells i n areas of immunopathology was identified by using a monoclonal antibo dy to a polymorphic determinant on HLA-DRw 52. RESULTS: We used a doub le antibody technique that employed monoclonal antibodies to HLA-DR an d KLA-DRw 52 antigens and placentae that were mismatched for the mater nal-fetal HLA-DRw 52 antigen. We found that the vast majority of immun ological cells within villi with inflammation were of maternal origin. Quantitative studies showed that between 75 and 100% of the cells in normal as well as in abnormal pregnancies were of maternal origin, and that abnormal pregnancies had a significantly higher percentage of vi lli with maternal cellular infiltrates. CONCLUSION: Our data show uneq uivocally that cells in areas of placental immunopathology are predomi nantly of maternal origin, and that abnormal pregnancies are associate d with significantly more villi containing immunological cells of mate rnal origin.