title: Evaluation of natural regulatory T cells in subjects with selective IgA deficiency: from senior idea to novel opportunities.
abstract: BACKGROUND
  Selective IgA deficiency (SIgAD) is the most common primary immunodeficiency disorder, which is characterized by significantly decreased serum levels of IgA. Abnormalities of CD4+CD25(high)forkhead box P3 (FoxP3)+ regulatory T cells (T(reg)) have been shown in association with autoimmune and inflammatory disorders.
  
  
  METHODS
  In order to evaluate the relationship between autoimmunity and T(reg) in SIgAD, we studied 26 IgA-deficient patients (aged 4-17 years) with serum IgA levels <7 mg/dl, 26 age- and sex-matched healthy controls and 26 age- and sex matched idiopathic thrombocytopenic purpura cases with normal immune system. T(reg) were determined by flow cytometry using T(reg) markers, including CD4, CD25 and FoxP3.
  
  
  RESULTS
  The mean percentage of CD4, CD25+FoxP3+ T(reg) from all CD4+ cells was 4.08 ± 0.86 in healthy controls, which was significantly higher than in SIgAD patients (2.93 ± 1.3; p = 0.003). We set a cutoff point (2.36%) for T(reg), which was two standard deviations lower than the mean of normal controls. According to this cutoff point and in order to assess the role of T(reg) in clinical SIgAD manifestation, we classified patients into two groups: 16 patients in G1 with T(reg) <2.36% and 10 patients in G2 with T(reg) >2.36%. Autoimmunity was recorded in 9 patients (53.3%) of G1 and only 1 patient of G2, respectively (p = 0.034). Although a defect in class switching recombination was observed in 40% of the patients in G1, none of the G2 patients had such a defect (p = 0.028).
  
  
  CONCLUSIONS
  This study showed decreased proportions of T(reg) in SIgAD patients, particularly in those with signs of chronic inflammation.
authors.affiliation: Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center, Tehran, Iran.
authors.forename: Habib
authors.initials: H
authors.lastname: Soheili
authors.forename: Hassan
authors.initials: H
authors.lastname: Abolhassani
authors.forename: Narges
authors.initials: N
authors.lastname: Arandi
authors.forename: Hossein Ali
authors.initials: HA
authors.lastname: Khazaei
authors.forename: Shervin
authors.initials: S
authors.lastname: Shahinpour
authors.forename: Armin
authors.initials: A
authors.lastname: Hirbod-Mobarakeh
authors.forename: Nima
authors.initials: N
authors.lastname: Rezaei
authors.forename: Asghar
authors.initials: A
authors.lastname: Aghamohammadi
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D017098:IgA Deficiency / Q000276:immunology* / Q000473:pathology; D008297:Male; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000473:pathology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000473:pathology