Major histocompatibility complex class I deficiency prolongs islet allograft survival.

Because of islet allograft rejection, nonimmunosuppressed pancreatic islet allotransplantation has been unsuccessful for the treatment of type I diabetes. The role of major histocompatibility complex class I antigen expression on islet allograft survival was evaluated with the use of mice homozygous for a beta 2-microglobulin gene disruption. These mice express little if any functional major histocompatibility complex class I antigen. When these major histocompatibility complex class I-deficient islets were used as donors in an allogenic murine transplantation model, islet allograft survival was markedly prolonged. These results demonstrate a major importance for the alloresponse directed against major histocompatibility complex class I antigen.