B lymphocyte antibodies associated with successful renal transplantation and successful pregnancy.

This study shows that non-cytotoxic Fc receptor blocking antibodies occurred more frequently in pre-transplant sera when the recipient had been transfused over five units of blood. Moreover 7/12 previously untransfused patients developed Fc receptor blocking antibodies during an elective blood transfusion regime. Erythrocyte antibody-rosette-inhibiting antibodies were also found at significantly higher values in the sera of women during the first trimester of a normal first pregnancy than in women studied at the time of spontaneous abortion. Family studies showed that this activity was linked to the HLA gene complex. These results indicate that EA inhibiting antibodies directed against MHC linked antigens are associated with specific abrogation of the immune response.