title: Characterization of lymphocytes that suppress IL-2 production in systemic lupus erythematosus.
abstract: IL-2 production by peripheral blood mononuclear cells (PBM) is decreased in patients with systemic lupus erythematosus (SLE). This defect can be reversed by the removal of CD8+ lymphocytes. The purpose of these studies was to determine whether the CD8+ IL-2 suppressor cells comprise a specific subset or whether all CD8+ cells have this activity. Lymphocyte subsets were identified and separated by two-colour flow cytometry prior to a 48 h mitogen stimulation. The CD8+ cells that suppressed IL-2 production co-expressed HLA DR and were radiosensitive. Other markers co-expressed by CD8+ cells which are found on suppressor cells such as Leu 15 (CD11), Leu 11 (CD16), and Leu 7 were also found on the CD8+ IL-2 suppressor cell population in SLE. In healthy subjects, removal of CD16+, but not of CD8+ cells markedly elevated the production of IL-2. The CD8- CD16+ non-T cell subset suppressed IL-2 production by normal and SLE PBM in autologous and allogeneic combinations. This subset may be a human equivalent of the murine natural suppressor cells. These results demonstrate that the cells that suppress IL-2 production in SLE are heterogeneous, and suggest that they belong to more than one lineage.
authors.affiliation: Department of Medicine, University of Southern California, School of Medicine, Los Angeles 910033.
authors.forename: M
authors.initials: M
authors.lastname: Linker-Israeli
authors.forename: J D
authors.initials: JD
authors.lastname: Gray
authors.forename: F P
authors.initials: FP
authors.lastname: Quismorio
authors.forename: D A
authors.initials: DA
authors.lastname: Horwitz
mesh_terms: D000943:Antigens, Differentiation / Q000032:analysis; D002469:Cell Separation; D005434:Flow Cytometry; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis*; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D013601:T-Lymphocytes / Q000145:classification*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000528:radiation effects
chemical_list: D000943:Antigens, Differentiation; D006684:HLA-DR Antigens; D007376:Interleukin-2