Donor HL-A incompatibility and lymphocytotoxic antibody response in human renal allotransplantation

When 81 recipients of primary renal allografts were examined for the influence of donor HL-A incompatibilities (DIC) on the survival of allografts, an association was found between greater DIC and not only an increased loss of allografts in the 1st year, but also a decreased survival of transplants in the subsequent years. However, three allografts with no DIC were rejected, whereas nine others with three to four imcompatibilities have functioned well for 1-5 years. A surprisingly high proportion (52%) of 81 renal allograft recipients produced lymphocytotoxic antibodies which lack HL-A specificity but apparently detect a polymorphic antigenic system on normal human lymphocytes. Only three patients who rejected the allografts made detectable circulating antibodies specific to DIC. However, when patients received grafts with fewer DIC, there was a greater number of no antibody or low frequency antibody producers, whereas with a greater number of DIC there was an increased occurrence of high frequency antibody producers. These results suggest that HL-A as well as non-HL-A systems may play a significant role in the success of allotransplantation. Although the presence of non-HL-A antibodies was not always associated with allograft loss, further characterization of these antibodies may reveal a new genetic system(s).