title: A decreased frequency of regulatory T cells in patients with common variable immunodeficiency.
abstract: BACKGROUND
  Common variable immunodeficiency disorder (CVID) is a heterogeneous syndrome, characterized by deficient antibody production and recurrent bacterial infections in addition abnormalities in T cells. CD4(+)CD25(high) regulatory T cells (Treg) are essential modulators of immune responses, including down-modulation of immune response to pathogens, allergens, cancer cells and self-antigens.
  
  
  OBJECTIVE
  In this study we set out to investigate the frequency of Treg cells in CVID patients and correlate with their immune activation status.
  
  
  METHODS
  Sixteen patients (6 males and 10 females) with CVID who had been treated with regular intravenous immunoglobulin and 14 controls were enrolled. Quantitative analyses of peripheral blood mononuclear cells (PBMC) were performed by multiparametric flow cytometry using the following cell markers: CD38, HLA-DR, CCR5 (immune activation); CD4, CD25, FOXP3, CD127, and OX40 (Treg cells); Ki-67 and IFN-gamma (intracellular cytokine).
  
  
  RESULTS
  A significantly lower proportion of CD4(+)CD25(high)FOXP3 T cells was observed in CVID patients compared with healthy controls (P<0.05). In addition to a higher proportion of CD8(+) T cells from CVID patients expressing the activation markers, CD38(+) and HLA-DR(+) (P<0.05), we observed no significant correlation between Tregs and immune activation.
  
  
  CONCLUSIONS
  Our results demonstrate that a reduction in Treg cells could have impaired immune function in CVID patients.
authors: Federal University of São Paulo, São Paulo, Brazil.
authors: Karina M
authors: KM
authors: Melo
authors: Karina I
authors: KI
authors: Carvalho
authors: Fernanda R
authors: FR
authors: Bruno
authors: Lishomwa C
authors: LC
authors: Ndhlovu
authors: Wassim M
authors: WM
authors: Ballan
authors: Douglas F
authors: DF
authors: Nixon
authors: Esper G
authors: EG
authors: Kallas
authors: Beatriz T
authors: BT
authors: Costa-Carvalho
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D017074:Common Variable Immunodeficiency / Q000097:blood / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D007371:Interferon-gamma / Q000096:biosynthesis; D019394:Ki-67 Antigen / Q000097:blood; D008213:Lymphocyte Activation; D008297:Male; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D055815:Young Adult
chemical_list: D019394:Ki-67 Antigen; D007371:Interferon-gamma