title: Thymectomy in early childhood: significant alterations of the CD4(+)CD45RA(+)CD62L(+) T cell compartment in later life.
abstract: The study was aimed to assess indicators of immunosenescence, such as the total counts of peripheral blood CD4(+)CD45RA(+)CD62L(+) (naive) T cells, the numbers of T cell receptor excision circles (TRECs), and Ki67-expression as marker of peripheral replication in thymectomized patients (TP) (n=101) compared to age-matched healthy donors (HD) (n=81). In TP, there was an inverse correlation between naive T cells and chronological age (p<0.001) or time post thymectomy (p<0.001). TP demonstrated lower TREC numbers in naive T cells compared to HD (p<0.001). TREC numbers negatively correlated with time post thymectomy (p<0.001). Percentages of Ki67-expresssing naive T cells were higher in TP compared to HD (p<0.05). The findings of the presented long-term follow up cohort of thymectomized patients indicate that changes of the peripheral naive T cell subset in TP may resemble the findings of an aging immune system in elderly persons after thymic involution. Our data provide evidence that peripheral T cell homeostasis in TP is maintained at minimal levels mainly by extrathymic expansion of existing naive T cells in the periphery to compensate the diminished thymic output.
authors.affiliation: Department of Pediatrics, Pediatrics I, Medical University Innsbruck, Anichstr. 35 A-6020 Innsbruck, Austria. Martina.Prelog@i-med.ac.at
authors.forename: Martina
authors.initials: M
authors.lastname: Prelog
authors.forename: Michael
authors.initials: M
authors.lastname: Keller
authors.forename: Ralf
authors.initials: R
authors.lastname: Geiger
authors.forename: Anita
authors.initials: A
authors.lastname: Brandstätter
authors.forename: Reinhard
authors.initials: R
authors.lastname: Würzner
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schweigmann
authors.forename: Manuela
authors.initials: M
authors.lastname: Zlamy
authors.forename: Lothar Bernd
authors.initials: LB
authors.lastname: Zimmerhackl
authors.forename: Beatrix
authors.initials: B
authors.lastname: Grubeck-Loebenstein
mesh_terms: D000293:Adolescent; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D016922:Cellular Senescence / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D006331:Heart Diseases / Q000151:congenital / Q000601:surgery; D006801:Humans; D019394:Ki-67 Antigen / Q000096:biosynthesis / Q000276:immunology; D019041:L-Selectin / Q000276:immunology; D017493:Leukocyte Common Antigens / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000097:blood*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013934:Thymectomy / Q000009:adverse effects*; D013950:Thymus Gland / Q000276:immunology* / Q000601:surgery; D055815:Young Adult
chemical_list: D019394:Ki-67 Antigen; D011948:Receptors, Antigen, T-Cell; D019041:L-Selectin; D017493:Leukocyte Common Antigens