Antiglobulin to cultured human lymphocytes (MAG) administered i.v. into human renal allograft recipients cannot be detected by immunofluorescent techniques on the basement membranes of graft biopsies. Antiglobulins to lymph nodes or thymus can be found bound to human renal allograft glomerular basement membranes (GBM) using identical immunofluorescent techniques. The use of the cultured lymphocyte produces an antilymphocyte globulin which will not produce direct renal damage.