title: Age-Related Differences in Percentages of Regulatory and Effector T Lymphocytes and Their Subsets in Healthy Individuals and Characteristic STAT1/STAT5 Signalling Response in Helper T Lymphocytes.
abstract: The dynamic process of the development of the immune system can in itself result in age-related immune malfunctions. In this study, we analysed lymphocyte subsets in the peripheral blood of 60 healthy donors, divided into groups of children, adolescents, and adults, focusing on effector (Teff) and regulatory (Treg) T lymphocytes and STAT1/STAT5 signalling response in helper T lymphocytes (Th) in adults, using flow cytometry. Our results demonstrate a decrease in the percentage of total Tregs and an increase in the percentage of total Teffs with age and a consequential immense increase in the Teff/Treg ratio. The increase of Teffs was most apparent in Th1, Th1Th17, and Th17CD161- subsets. Significant Th lymphocyte STAT1 expression differences were observed between children and adolescents, which were associated with the decrease in activated Tregs. Higher expression of STAT1 was found in FoxP3hi than in FoxP3low Th lymphocytes, while significant IL-2 induced STAT5 phosphorylation differences were found among the subsets of Th lymphocytes in adults. Our study demonstrates age-related changes in circulating Teff and Treg, as well as significant differences in STAT5/STAT1 signalling among FoxP3+ Th lymphocytes, providing new advances in the understanding of immunosenescence.
authors.affiliation: Department of Allergology, Rheumatology and Clinical Immunology, University Children's Hospital, University Medical Centre Ljubljana, Bohoričeva 20, SI-1525 Ljubljana, Slovenia.
authors.forename: Marija
authors.initials: M
authors.lastname: Holcar
authors.affiliation: Department of Laboratory Diagnostics, University Medical Centre Maribor, Ljubljanska Ulica 5, SI-2000 Maribor, Slovenia ; Faculty of Medicine, University of Maribor, Taborska Ulica 8, SI-2000 Maribor, Slovenia.
authors.forename: Aleš
authors.initials: A
authors.lastname: Goropevšek
authors.affiliation: Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Zaloška 4, SI-1000 Ljubljana, Slovenia.
authors.forename: Alojz
authors.initials: A
authors.lastname: Ihan
authors.affiliation: Department of Allergology, Rheumatology and Clinical Immunology, University Children's Hospital, University Medical Centre Ljubljana, Bohoričeva 20, SI-1525 Ljubljana, Slovenia ; Department of Pediatrics, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, SI-1000 Ljubljana, Slovenia.
authors.forename: Tadej
authors.initials: T
authors.lastname: Avčin
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging; D002648:Child; D002675:Child, Preschool; D005260:Female; D005434:Flow Cytometry; D064368:Healthy Volunteers; D006801:Humans; D000068884:Immunosenescence; D007223:Infant; D007376:Interleukin-2 / Q000276:immunology; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D050794:STAT1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D050799:STAT5 Transcription Factor / Q000378:metabolism*; D015398:Signal Transduction; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000378:metabolism*; D050378:T-Lymphocytes, Regulatory / Q000378:metabolism*; D058504:Th17 Cells / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000378:metabolism*; D055815:Young Adult
chemical_list: D007376:Interleukin-2; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D050799:STAT5 Transcription Factor; C494092:STAT5A protein, human; D025521:Tumor Suppressor Proteins