Antibody-dependent and direct lymphocyte-mediated cytotoxicity in patients on hemodialysis

Twenty-two patients on chronic hemodialysis were tested for direct lymphocyte-mediated cytotoxicity (DCML) and antibody-dependent lymphocyte-mediated cytotoxicity (LALI) against selected panels of normal donor lymphocytes. The DCML reaction was only positive in patients who had received blood transfusions within the two or three months prior to testing. Thus this reaction has limited value in practice as a parameter for presensitization. The use of third-party effector cells and of target cells precoated with antibody in the LALI reaction was evaluated, and it is advocated that effector cells from the patient investigated and direct application of patient serum to reaction mixtures should be preferred in order to avoid false negative reactions. In patients who had once manifested lymphocytotoxins, LALI disclosed a much broader reactivity than seen with a conventional complement-dependent cytotoxicity technique (CDC), whereas in this study patients who had never developed cytotoxins were also negative with the LALI technique. It is concluded that a positive LALI cross-match, in spite of a negative CDC cross-match, will be a common finding in donor-recipient combinations where the recipient has preformed cytotoxins. The effect of this on subsequent graft prognosis needs further clarification.