title: Comparison of major lymphocyte subpopulations and recent thymic emigrants in patients with ataxia telangiectasia and age-matched healthy groups.
abstract: BACKGROUND
  Ataxia telangiectasia (A-T) is a genetic disorder caused by the homozygous mutation of the A-T mutated gene. It is frequently associated with variable degrees of cellular and humoral immunodeficiency. However, the immune defects in A-T patients are not well characterized. To the best of our knowledge, no studies have focused on the major lymphocyte subpopulations and recent thymic emigrants of A-T patients in comparison with age-matched healthy controls.
  
  
  METHODS
  Following the European Society for Immunodeficiencies criteria, 17 patients diagnosed with A-The, and 12 age-matched healthy children were assigned to the study. Both patients and healthy controls were grouped as 1-5, 6-10, 11-15, and 15+ years. By using a flow cytometer, major lymphocyte subpopulations and CD4+CD45RA+CD31+ recent thymic emigrants were determined as percentage and absolute cell numbers and compared.
  
  
  RESULTS
  No significant differences in all lymphocyte subpopulations were observed between the age groups of A-T patients. Compared to the healthy controls, there was a decrease in T cells, effector memory T4 cells, B cells, naïve B cells, naïve T4 cells, switched B cells, and recent thymic emigrants and an increase in active T8 cells and non-switched B cells in the percentage and absolute number of some cell populations in the A-T group.
  
  
  CONCLUSIONS
  This study showed that effector functions in some cell lymphocyte populations were decreased in A-T patients.
authors.affiliation: Ondokuz Mayıs University, Medical Faculty, Department of Pediatric Allergy and Immunology, Samsun, Turkey. Electronic address: drmhc@hotmail.com.
authors.forename: M H
authors.initials: MH
authors.lastname: Celiksoy
authors.affiliation: Inonu University, Medical Faculty, Department of Pediatric Allergy and Immunology, Malatya, Turkey.
authors.forename: E
authors.initials: E
authors.lastname: Topal
authors.affiliation: Ondokuz Mayıs University, Medical Faculty, Department of Pediatric Allergy and Immunology, Samsun, Turkey.
authors.forename: A
authors.initials: A
authors.lastname: Yıldıran
mesh_terms: D000293:Adolescent; D001260:Ataxia Telangiectasia / Q000276:immunology*; D015415:Biomarkers / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D017493:Leukocyte Common Antigens / Q000378:metabolism; D018655:Lymphocyte Count; D016131:Lymphocyte Subsets / Q000378:metabolism*; D008297:Male; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D055815:Young Adult
chemical_list: D015415:Biomarkers; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D017493:Leukocyte Common Antigens
keywords: Ataxia–telangiectasia; CD31; Immunodeficiency; Lymphocyte subpopulation; PECAM-1; Recent thymic emigrants