[Morphological changes in the healing process of mixed grafts in animal studies with reference to the immunological modification processes based on sex-specific chromosome analysis. A cytogenetic and histological study in rats].

In the rat, free skin grafts exchanged between genetically different clones were completely rejected after three weeks. These transplants were not rejected when island autografts were set into preformed holes in the allografts. A typical graft-rejection pattern in the mixed skin transplants showed initial healing of the alloepidermis, which was later replaced by outgrowing autoepidermis from the interspersed islands. Since the autoepidermis covers the allocorium directly, it appears much like normal skin. In a few cases, connective tissue formed between the new autoepidermis and the remaining allodermis. Fibrous tissue streaks were also found between the otherwise unchanged allodermis layer and the muscle fascia. The remaining allocorium could still be found 111 days after transplantation using cytogenetic techniques and chromosome analysis. Mixed skin grafts consist of cell mosaics including cell lines form the donor and the recipient, with the corium structures completely retained. Cellular and humoral infiltration was not found to be part of the rejection process.