title: Both normal memory counts and decreased naive cells favor intrinsic defect over early senescence of Down syndrome T lymphocytes.
abstract: Because of their increased malignancies, autoimmune diseases, and infections, patients with Down syndrome (DS) show features of immunodeficiency. The DS thymus and T lymphocyte subsets have indeed proven to be different, and this has been interpreted as precocious aging. Our study on T lymphocyte subpopulations in DS shows that the normal expansion of naive helper (CD4CD45RA) and cytotoxic (CD8CD45RACD27) T lymphocytes is lacking in the first years of life; this is more logically explainable with an intrinsic T lymphocyte defect. Furthermore, memory cell numbers are not different from age-matched controls (AMC), which does not support the hypothesis of precocious aging. Although the absolute numbers of T lymphocyte subpopulations approach AMC levels toward adulthood, the persistent clinical problems suggest that these cells may not function optimally. However, the clinical picture does not fit severe T lymphocyte deficiency. The latter concept is also supported by our finding that cytomegalovirus (CMV)-seropositive DS children show similar numbers of terminally differentiated cytotoxic T lymphocytes when compared with healthy children, not increased numbers as are seen in immunocompromised hosts.
authors.affiliation: Departments of Pediatrics, Jeroen Bosch Hospital, 's-Hertogenbosch, 5200 ME, The Netherlands.
authors.forename: Maaike A A
authors.initials: MA
authors.lastname: Kusters
authors.forename: Eugenie F A
authors.initials: EF
authors.lastname: Gemen
authors.forename: Ruud H J
authors.initials: RH
authors.lastname: Verstegen
authors.forename: Peter C
authors.initials: PC
authors.lastname: Wever
authors.forename: Esther
authors.initials: E
authors.lastname: DE Vries
mesh_terms: D000293:Adolescent; D000914:Antibodies, Viral / Q000097:blood; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000821:virology; D016922:Cellular Senescence; D002648:Child; D002675:Child, Preschool; D003587:Cytomegalovirus / Q000276:immunology; D004314:Down Syndrome / Q000276:immunology*; D005260:Female; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000276:immunology*; D007156:Immunologic Memory; D016130:Immunophenotyping; D007223:Infant; D018655:Lymphocyte Count; D008297:Male; D012189:Retrospective Studies; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000821:virology; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral