title: CD4+ cells from patients with Common Variable Immunodeficiency have a reduced ability of CD40 ligand membrane expression after in vitro stimulation.
abstract: BACKGROUND
  Common Variable Immunodeficiency (CVID) is characterized by defective antibody production. This has been variably attributed to intrinsic B-cell defects or to T-cell disfunctions. Recently, it has been reported that the expression of the CD40 Ligand (CD40L), a T-cell surface molecule that plays a critical role in the cell-contact-mediated helper signals provided to B-cells, is defective in a subset of patients with CVID.
  
  
  METHODS
  To demonstrate that the defective expression is due to intrinsic functional abnormalities of CD4+ lymphocytes, CD4+ cells were purified from eight patients with CVID and eight age-paired controls, stimulated with PMA+Ionomycin, and studied for CD40L expression by flow cytometry using specific monoclonal antibodies.
  
  
  CONCLUSIONS
  The percentage of CD4+ cells expressing CD40L after optimal stimulation was correlated with age both in patients with CVID (r: 0.74; p: 0.04) and in healthy controls (r: 0.73; p: 0.04). The percentage of CD40L+ cells was reduced in patients with CVID compared to that of controls (p: 0.02 when data are paired for age) with a reduced density of expression (p: < 0.01). The defect was variable in different patients and in some cases it was marginal.
authors.affiliation: Servizio di Immunologia Clinica, Spedali Civili, Brescia, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Brugnoni
authors.forename: P
authors.initials: P
authors.lastname: Airò
authors.forename: M
authors.initials: M
authors.lastname: Lebovitz
authors.forename: F
authors.initials: F
authors.lastname: Malacarne
authors.forename: A G
authors.initials: AG
authors.lastname: Ugazio
authors.forename: L D
authors.initials: LD
authors.lastname: Notarangelo
authors.forename: A
authors.initials: A
authors.lastname: Plebani
authors.forename: R
authors.initials: R
authors.lastname: Cattaneo
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D015496:CD4-Positive T-Lymphocytes / Q000737:chemistry*; D023201:CD40 Ligand; D002648:Child; D017074:Common Variable Immunodeficiency / Q000276:immunology*; D005260:Female; D006801:Humans; D008213:Lymphocyte Activation; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis*
chemical_list: D008562:Membrane Glycoproteins; D023201:CD40 Ligand