Monoclonal antibodies in immunosuppression

Experimental and clinical studies have been carried out to investigate the application of a number of monoclonal antibodies which recognise human lymphocytes in clinical organ transplantation. Where possible, preliminary studies have been carried out using a primate renal allograft model before proceeding to clinical pilot studies. The Campath-1 antigen (CDW52) appears to be a good target for antilymphocytic therapy; a powerful immunosuppressive effect has been demonstrated using both IgM and IgG2b antibodies which recognise this antigen. An IgG2b antibody which recognises the IL-2 receptor was shown to be immunosuppressive in the primate model but clinical studies have, as yet not demonstrated a significant, beneficial effect in preventing rejection. Patients who receive antilymphocyte monoclonal antibodies require monitoring of the expression of the target antigen, the level of free antibody in serum and the development of an antiglobulin response. The current issues in the use of antilymphocyte monoclonal antibodies in clinical immunosuppression include identification of the optimum target, interaction of the antibody with recipient effector mechanisms and methods to avoid or suppress the antiglobulin response.