Detection by membrane immunofluorescence of isoantibodies during rejection of skin allografts.

Isoantibodies which react strongly and specifically with donor lymphocytes have been demonstrated by membrane immunofluorescence in the sera of mice and rabbits bearing first and second set allografts of skin. Changes in the titre of these antibodies closely paralleled the course of the rejection reaction. With other types of cells the immunofluorescent staining was less intense and the reactions were less consistent. Staining was completely inhibited by serum absorption with spleen, lymph node or thymus, but myocardium, aorta or tendon had no specific absorbing effect. The antibodies detected are probably directed against histocompatibility antigens.