Antibody-dependent cell-mediated destruction of human erythrocytes sensitized in ABO and rhesus fetal-maternal incompatibilities.

Antibody-dependent cell-mediated cytotoxicity (ADCMC) was measured in a 51Cr-release assay with antibody-sensitized human red blood cells (RBC) as target cells and nonimmune isologous or autologous mononuclear peripheral blood leukocytes (MPBL) as effector cells. ADCMC was readily demonstrable within 6 hr and was independent of exogenous complement (C'). The specificity of the ADCMC reaction was determined by the antiserum employed. Anti-A, anti-B, anti-D, and anti-c sera were all active in ADCMC; the specific lysis was between 35 and 50% with antiserum dilution of 1/1,000, using 10(5) target cells and 10(6) MPBL. Anti-C, anti-E, and anti-e sera had no detectable activity. Sephadex column separation suggested that this activity was by antibodies of the IgG class. Cord RBC from infants with RhD fetal-maternal incompatibility were lysed by autologous or isologous MPBL in the absence of exogenous antiserum. ADCMC was between 22% and42% in cases with high direct Coombs' test, but was negative with low direct Coombs' test as in five cases of ABO incompatibility.