title: Characterization of circulating suppressor T lymphocytes in bone marrow transplant recipients.
abstract: Peripheral blood T lymphocytes from 21 bone marrow transplant (BMT) patients and normal controls were studied for surface expression of HLA-DR, HLA-DQ, and classic T cell markers, including Leu 2, Leu 3, and Leu 4. Although resting T cells from normal subjects did not express HLA-DR or HLA-DQ molecules, up to 86% (range 22-86%) of T cells from BMT recipients expressed HLA-DR. Interestingly, less than or equal to 8% of the cells expressed HLA-DQ, and less than or equal to 3% had receptors for interleukin-2 (IL-2). When T lymphocytes were harvested from BMT recipients one month postransplant, they failed to produce IL-2 constitutively or after stimulation with various mitogens. Further analysis of patient cells revealed that 20-67% of their T lymphocytes were positive for both Leu 2 and Leu 15 (2+, 15+; normal range = 5-8%). Since 2+, 15+ cells from normal subjects have potent suppressor activity, we tested whether the cells from BMT recipients would suppress production of IL-2 from normal cells. In coculture studies, we found that cells from 5/5 BMT patients suppressed normal IL-2 production up to 70%. If patient cells were irradiated (3000 rads) prior to coculture, suppressor activity was abrogated. We propose that the cells described here may play a prominent role in the slow recovery of the immune system in BMT recipients.
mesh_terms: D000741:Anemia, Aplastic / Q000628:therapy; D000911:Antibodies, Monoclonal; D001853:Bone Marrow / Q000276:immunology; D016026:Bone Marrow Transplantation; D002478:Cells, Cultured; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis; D009369:Neoplasms / Q000628:therapy; D012016:Reference Values; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D006684:HLA-DR Antigens; D007376:Interleukin-2