Cross-reactions to skin homografts in man.

A considerable array of evidence has been secured to suggest that the tempo and intensity of the host's immune response to tissue transplants are conditioned by the degree of histocompatibility existing between the individuals studied (1-4). Although this subject has received a great deal of attention in animal species, it has not been studied extensively in man (5-7). The present report is concerned with the infl-enice of genetic disparity upon the fate of skin homografts in man. The results of a 9-year study of 147 skin homografts performed in a group of unrelated normal subjects are presented and discussed in the light of observed variations in the individual specificity of the rejection reaction. Selection of skin homograft donors and recipients. The subj ects were students and house officers of the Third and Fourth Medical and Surgical Divisions (New York University) at Bellevue Hospital, New York. The donors were individuals known not to transmit serum hepatitis on the basis of their previous record of skin or blood donations at Bellevue Hospital. Technique of grafting and of graft observation. The skin specimens were removed from the donors under 1 per cent procaine local anesthesia, and anchored to the host bed with 5-0 interrupted nylon sutures. The grafts were full-thickness specimens 11 mm in diameter. They were placed on the anterior surface of the forearm of the recipient. Pressure dressings were applied and changed 2 days later. On the fourth day, they were replaced by Band-aids. The grafts were observed daily after the second day with a Bausch and Lomb dissecting stereomicroscope. Magnifications of 19.5, 45, and 90 times were employed to examine the graft surface and permit the accurate visualization of blood flow in the superficial blood vessels of the graft (8). Criteria for the determination of homograft rejection. The objective determination of the time of onset of ho-mograft' rejection was based upon the results of gross and stereomicroscopic observations. The graft surface capillaries were studied daily by the method of Taylor and Lehrfeld (9, 10) adapted to man in the course of an initial study of the rejection of human skin homografts (8). This method permits the accurate visual determination of successful graft vascularization, as well as of the graft rejection changes. The criteria for graft rejection include: 1) cessation of blood flow and thrombosis of the graft vessels, 2) cyanosis and edema of the graft, and 3) development of erythema …