Cultured thymus tissue transplantation promotes donor-specific tolerance to allogeneic solid organ transplants

A method for promoting donor-specific tolerance to an allogeneic solid organ transplant obtained from a human donor, in a human recipient in need of a solid organ transplant, the method comprising the steps of:

• (a) removal of the thymus of the recipient;
• (b) treating the recipient with an induction immunosuppressive regimen comprising one or more immunosuppressive agent to deplete the recipient's T cells and/or to suppress the recipient's T cells from rejecting the transplanted solid organ;
• (c) providing a suitable solid organ from a human donor;
• (d) transplanting the solid organ into the recipient;
• (e) treating the recipient with a maintenance immunosuppressive regimen;
• (f) providing a cryopreserved allogeneic cultured postnatal thymus tissue-derived product maintained in a cryopreserved allogeneic cultured postnatal thymus tissue-derived product bank;
• wherein the cryopreserved allogeneic cultured postnatal thymus tissue-derived product is processed from thymus tissue from a thymus donor expressing HLA alleles matched to HLA alleles in the recipient that are not present in the solid organ transplant;
• wherein the donor thymus tissue has been processed into donor thymus tissue slices, wherein the donor thymus tissue slices have been assessed by pathology and show >50% of areas positive for keratin in a lacy staining pattern, show Hassall bodies, show cytokeratin 14 (CK14) staining in a lacy pattern, and show >90% intact nuclei of thymic epithelial cells and other stromal cells, wherein the donor thymus tissue has been subjected to a conditioning regimen for a period up to 12 days;
• wherein the conditioning regimen for the donor thymus tissue comprises aseptically processing the donor thymus tissue in a thymus organ medium to produce partially T-cell depleted thymus tissue slices, wherein the partially T-cell depleted thymus tissue slices are assessed by pathology and, between day 5 and 9 of the conditioning regimen, show staining positive for keratin, show CK14 staining scattered throughout, show at least one Hassall body, and show intact nuclei of thymic epithelial cells and other stromal cells;
• (g) thawing the cryopreserved allogeneic cultured postnatal thymus tissue-derived product;
• and
• (h) implanting the thawed cryopreserved allogeneic cultured postnatal thymus tissue-derived product into the recipient, wherein the dosage of the cryopreserved allogeneic cultured postnatal thymus tissue-derived product is about 1,000-20,000 mm2 of thymus tissue surface area/recipient body surface area in m2, and further wherein the implanted allogeneic cultured postnatal thymus tissue-derived product induces thymopoiesis and tolerance in the recipient.