HLA and red blood group antigens in pregnancy disorders

Total of 356 women with various types of pregnancy disorders as well as their husbands were classified in four groups regarding the type of the disorder as follows: 1. Recurrent spontaneous abortions (RSA) of unknown etiology (N = 105) and RSA - primary aborters only (N = 84); 2. Blighted ovum (N = 80); 3. Rh immunization in pregnancy (N = 90); 4. ABO immunization in pregnancy (N = 47). Two groups of couples were used as controls: 1. Couples randomly taken from forensic medicine cases of paternity evaluation (N = 104); 2. Couples having two or more children with HLA immunization in pregnancy (N = 78). The couples from all groups were typed for red blood group antigens of ABO, Rhesus, MNSs, Kell, Duffy, Lewis, Kidd and P systems and also for HLA antigens. Significantly higher frequency of antigen HLA-A9 was found in women with RSA (corr. p = 0.0003) and in women with pregnancy disorders caused by Rh immunization (corr. p = 0.0136). In couples with RSA the degree of HLA compatibility was significant (p = 0.0048) and the reactivity of spouses in MLR was significantly decreased (p = 0.0001). Significantly, more low responders in MLR were also found among the women with RSA as compared to the controls (p = 0.0217). Two possible pathologic mechanisms may explain the association between HLA antigens and RSA: 1. immunological defects which are linked to HLA-D/DR region causing malfunction of immunosuppressive mechanisms during pregnancy; 2. endocrinological defect which is linked to HLA region as 21-OH hydroxylase deficiency gene.