Serum autoleukocytotoxic activity and the positive cross-match in potential allograft recipients

To evaluate possible causes of the false-positive cross-match test for clinical renal transplantation, the incidence of serum autoleukocytotoxic activity and its relationship to allogeneic sensitization to HLA antigens (the positive cross-match) were determined in 234 sera from 28 sensitized and eight nonsensitized chronic renal failure patients. Seven sera from four patients had autoleukocytotoxic activity. The autoleukocytotoxic activity was detected only in patients who showed transient allogeneic sensitization at some point. This activity could be adsorbed either by autologous or allogeneic platelets, but adsorption with autologous platelets did not remove the synchronous allogeneic leukocytotoxicity. This autoleukocytotoxic activity appears to coexist with alloreactive antibody, and in such a setting the positive alloreactive cross-match should contraindicate the proposed transplant until adsorption studies prove the false-positiveness of the test.