title: Thymic function and impaired maintenance of peripheral T cell populations in children with congenital heart disease and surgical thymectomy.
abstract: The thymus begins involution in childhood and historically it was thought to be nonfunctional by adulthood, thus presenting no contraindication to the routine practice of thymectomy during cardiothoracic surgery. More recent data suggest, however, that the thymus remains active into adulthood and is responsible for the low-level production of normal T cells. We hypothesize, therefore, that incidental thymectomy during cardiothoracic surgery in infancy causes long-term changes in the cellular immune system. To investigate this hypothesis, we quantified peripheral T-cell subsets and T-cell recombination excision circles in children with congenital heart disease to measure the impact of cardiothoracic surgical procedures and thymectomy performed during a period of immunologic development. We found that cardiothoracic surgical procedures, especially if they include thymectomy, impair T-cell production and produce long-term decreases in total lymphocyte count and CD4(+) and CD8(+) T-cell subsets, suggesting that long-term maintenance of lymphocyte populations is disturbed.
authors.affiliation: Division of Pediatric, David Geffen School of Medicine at the University of California, Los Angeles, CA 90095, USA.
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Halnon
authors.forename: Beth
authors.initials: B
authors.lastname: Jamieson
authors.forename: Mark
authors.initials: M
authors.lastname: Plunkett
authors.forename: Christine M R
authors.initials: CM
authors.lastname: Kitchen
authors.forename: Thao
authors.initials: T
authors.lastname: Pham
authors.forename: Paul
authors.initials: P
authors.lastname: Krogstad
mesh_terms: D000293:Adolescent; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology; D002469:Cell Separation; D002648:Child; D002675:Child, Preschool; D004247:DNA / Q000378:metabolism; D005434:Flow Cytometry; D006330:Heart Defects, Congenital / Q000473:pathology* / Q000601:surgery*; D006801:Humans; D007223:Infant; D018655:Lymphocyte Count; D016131:Lymphocyte Subsets / Q000166:cytology; D011948:Receptors, Antigen, T-Cell / Q000235:genetics; D011995:Recombination, Genetic; D013601:T-Lymphocytes / Q000378:metabolism*; D013950:Thymus Gland / Q000473:pathology* / Q000601:surgery*; D013997:Time Factors
chemical_list: D011948:Receptors, Antigen, T-Cell; D004247:DNA