Heterologous Antilymphocyte Globulin

The immunosuppressive properties of heterologous antilymphocyte serum and its globulin derivative have been well known since 1961, when it was reported that a variety of immunologic responses could be weakened in guinea pigs by the administration of the antilymphocyte serum or its globulin derivative that had been raised in rabbits. 1 These included the marked suppression of delayed cutaneous hypersensitivity, a lesser effect on humoralantibody formation and a relatively feeble mitigation of skin homograft rejection.Soon afterward, it was unequivocally demonstrated 2-5 that rabbit anti-lymphocyte serum had remarkable ability to prolong the viability of mouse or rat skin grafts even when they were transplanted across difficult histocompatibility barriers.Moreover, such an effect could often be obtained with less overt toxicity than with any previously known immunosuppressive agent.As a consequence of these results, there was immediate interest in the possible clinical use of antilymphocyte globulin after human organ transplantation or for the treatment of various other immunologically directed pathologic states.It now seems clear that the globulin can be administered to man with both benefit and relative safety in spite of certain gaps in knowledge, which are alluded to below, but only under carefully controlled circumstances.