Survival of ovarian allografts in an experimental animal model

Transplantation of ovarian tissue is a promising strategy for fertility preservation in young cancer patients with premature ovarian failure if they have cryopreserved their own tissue before undergoing gonadotoxic treatment. However, extension of ovary donation to children and adults seeking treatment for hypogonadism is controversial unless the tissue does not provoke an immune reaction or specific tolerance can be safely and effectively achieved. The survival of heterotopic ovarian allografts was tested in a mouse model. Isografts were placed under the kidney capsule of ovariectomized animals differing at the H-2 haplotype (H-2d or H-2k). Within three wk, and in contrast to isografts, the allografts were rejected, although their survival was extended when donor and host strains shared the same haplotype (H-2k). Allograft survival was not improved if the tissue was implanted orthotopically. When monoclonal antibodies to CD4 antigens were administered at doses exceeding those effective for long-term tolerance to cardiac allografts, graft survival was prolonged in one of two strain combinations, but they failed to restore fertility. These results indicate that the ovary is not an immunologically privileged organ, as the older literature suggested, and chronic immunosuppression is likely to be required for ovarian allografts in clinical settings.