Immunoregulatory CD4+ CD45R+ suppressor/inducer T lymphocyte subsets and impaired cell-mediated immunity in patients with Down''s syndrome. |
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Authors: | S Raziuddin and M E Elawad |
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Affiliation: | Department of Clinical Immunology, King Saud University, College of Medicine, Abha, Saudi Arabia. |
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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. |
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Keywords: | Down's syndrome CD4+ T cell subsets CD4+ CD45R+ T cellsCD4+ CDW29+ T cells phytohaemagglutinin concanavalin A |
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