title: An increased frequency of IgE-producing B cell precursors contributes to the elevated levels of plasma IgE in atopic subjects.
abstract: BACKGROUND
  The production of specific IgE, which underlies the allergic response, may be a normal correlate of the immune response to a certain class of antigen (allergens), or could represent a unique response driven by regulatory signals that are absent in non-allergic individuals. If atopic subjects do possess a regulatory environment favoring IgE production, they may display not only allergen-specific IgE, but also higher levels of total IgE and higher frequencies of IgE-producing B lymphocytes.
  
  
  OBJECTIVE
  To address the contribution of antibody-producing cell number to the circulating IgE titre in atopic vs non-atopic subjects.
  
  
  METHODS
  Frequency determination by limiting dilution of EBV transformants and Poisson distribution analysis. Titres of total and allergen-specific IgM, IgG, and IgE by specific ELISA.
  
  
  RESULTS
  In contrast to findings reported by others, the atopic subjects had a significantly higher frequency of IgE-producing B cells than non-atopics (0.79% of total Ig-producing cells, as compared with 0.17% for the control group; P < 0.01), suggesting that one factor contributing to the high plasma IgE titres in atopic subjects is the high frequency of B lymphocytes with the potential to produce IgE. Although only the atopic subjects produced allergen-specific IgE, the frequency of specific IgE-producing B cells was undetectable in both groups.
  
  
  CONCLUSIONS
  Atopic subjects have higher frequencies of IgE-producing B cell precursors than non-atopics. A correlation exists between IgE-producing B cell frequency and levels of circulating IgE.
authors.affiliation: ImmuLogic Pharmaceutical Corporation, Waltham, MA 02154, USA.
authors.forename: M T
authors.initials: MT
authors.lastname: Kasaian
authors.forename: C H
authors.initials: CH
authors.lastname: Meyer
authors.forename: A K
authors.initials: AK
authors.lastname: Nault
authors.forename: J F
authors.initials: JF
authors.lastname: Bond
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D006412:Hematopoietic Stem Cells / Q000276:immunology*; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology*; D007073:Immunoglobulin E / Q000096:biosynthesis / Q000097:blood*; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008925:Mites / Q000276:immunology
chemical_list: D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007073:Immunoglobulin E