CROSS-REACTIONS TO SKIN HOMOGRAFTS IN MAN*

Abstract

Variations in the specificity of skin homograft reactions were studied in 147 normal unrelated humans. Primary exposure to a skin homograft from one donor is associated with development in the recipient of generalized altered reactivity to subsequent grafts from the same individual, but not from other individuals. Depending upon the latent period after the first graft, this reactivity is expressed in terms of accelerated rejection or of the white graft reaction when the subject is exposed to a second graft from the same donor. However recipients who have been hypersensitized with several grafts from a same donor may respond with accelerated rejection when they are subsequently exposed to a graft from another unrelated individual. Such cross-reactions suggest that unrelated human subjects may share tissue transplantation antigens. An evaluation of the contribution of hypersensitization to the occurrence of the cross-reactions observed in this study must await the identification and characterization of the homograft antigens.