Thymic epithelial cell transplantation in patients with acquired immunodeficiency syndrome. Evidence for infection by HIV-I of newly differentiated T cells at the site of transplantation.

From October 1983 to July 1984, 11 adult AIDS patients have received single or repeated thymic grafts. All have had opportunistic infections and 3 also had Kaposi's sarcoma. Thymic tissue from infants undergoing cardiac surgery was cultured to provide a thymocyte- and fibroblast-free epithelial cell inoculum. 18-21 days post-explantation, cells and explants were injected intraperitoneally, intramuscularly or intrahepatically. Transplants were well tolerated in all cases. In 7 cases liver biopsy was performed at the time of grafting and 2 months later. Ten patients have died after a mean survival time following transplantation of 8.7 months while 1 patient was lost to follow up. Clinical improvement and absence of new opportunistic infections were apparent for 4 months following transplantation. Partial immunoreconstitution was evidenced by an increase in peripheral blood lymphocytes (8 of 10 cases) and lymphocyte subsets (7 of 10 cases) as well as by presence of T4 and T8 positive cells in the liver (5 of 7 cases). In 5 of 7 patients, double-staining immunofluorescence showed that HIV-I antigens were present in T4-phenotype cells, at the site of the graft, 2 months after grafting, but were not detected in the liver at the time of grafting. Transient immunoreconstitution, therefore, maybe related to destruction of newly differentiated T lymphocytes.