Subpopulations of lymphocytes in maternal peripheral blood during pregnancy

The fetus can be considered an allograft with up to one-half of its MHC antigens being potentially recognized by the mother as foreign. This study compares expression of OKT3, OKT4, OKT8, Kappa, Lambda and Ia antigens on lymphocytes in the peripheral blood of normal non-pregnant women, normal pregnant women, patients who are chronic spontaneous aborters and pregnant insulin-dependent diabetic women. Monoclonal antibodies and cytofluorometric analyses were used for these determinations. There were no significant differences (P = 0.01) between these groups for T-cell markers. A statistically significant (P = 0.001) increased ratio of cells bearing surface immunoglobulin to those expressing Ia antigen (K&L/Ia) was observed between normal non-pregnant controls and women with a history of chronic spontaneous abortion. It is concluded that T-lymphocytes in the peripheral blood do not demonstrate a phenotypic abnormality that would account for the non-rejection of the fetal allograft; however, women with chronic spontaneous abortion may have abnormal B-cell differentiation or T-cell activation that mediates chronic spontaneous abortion.