title: Immunoregulatory CD4+ CD45R+ suppressor/inducer T lymphocyte subsets and impaired cell-mediated immunity in patients with Down's syndrome.
abstract: The monoclonal antibodies 2H4 and 4B4 allow CD4+ and CD8+ T lymphocytes to be subdivided into CD45R+ and CDW29+ functional subpopulations. The CD4+ CD45R+ lymphocytes are designated as suppressor/inducer and CD4+ CDW29+ as helper/inducer subsets. Peripheral blood lymphocytes from 19 patients with Down's syndrome and 19 age- and sex-matched normal controls were analysed for the CD45R+ and CDW29+ subsets from the CD4+ and CD8+ T lymphocytes. The percentage of CD4+ CD45R+ cells (suppressor inducer) was markedly increased and of CD4+ CDW29+ cells (helper/inducer) decreased in all patients with Down's syndrome. In contract, the percentage of CD8+ CD45R+ and CD8+ CDW29+ subsets showed no major differences between patients with Down's syndrome and normal controls. Moreover, an alteration in the CD4+ and CD45R+ and CD4+ CDW29+ T cell subsets was accompanied by a markedly reduced proliferative response to phytohaemagglutinin and concanavalin A stimulation of the CD4+ T lymphocytes. Thus, a deficiency exists in patients with Down's syndrome in the CD4+ CDW29+ helper/inducer T cell subset which may contribute to their impaired cell-mediated immunity.
authors.affiliation: Department of Clinical Immunology, King Saud University, College of Medicine, Abha, Saudi Arabia.
authors.forename: S
authors.initials: S
authors.lastname: Raziuddin
authors.forename: M E
authors.initials: ME
authors.lastname: Elawad
mesh_terms: D000943:Antigens, Differentiation / Q000032:analysis*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D004314:Down Syndrome / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular; D007223:Infant; D017493:Leukocyte Common Antigens; D007958:Leukocyte Count; D008213:Lymphocyte Activation; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D000943:Antigens, Differentiation; D017493:Leukocyte Common Antigens