What are the characteristics of asthma patients with elevated serum IgG4 levels?

Respir Med. 2016 Mar;112:39-44. doi: 10.1016/j.rmed.2016.01.014. Epub 2016 Jan 22.

Abstract

Introduction: IgG4 has recently been a subject of great interest in human pathology. No data are available about the characteristics of asthma patients with elevated IgG4 levels.

Population and methods: An observational study was conducted from January 2006 to March 2015 in a difficult-to-treat population of asthma patients. Twenty-six difficult-to-treat asthma patients with elevated serum IgG4 levels (IgG4/IgG ratio up to 10%) were compared with a control population of 98 difficult-to-treat asthma patients with normal serum IgG4. Blood eosinophilia, total IgE and FeNO were compared between groups to better characterize asthma patients with elevated serum IgG4 levels.

Results: Median IgG4 concentrations were 1.72 g/l [1.19-2.36] and 0.22 g/l [0.10-0.49] in the elevated IgG4 group and normal Ig4 group, respectively. Median blood eosinophilia was more than three times higher in patients with elevated serum IgG4 levels than in controls (0.75 10(9)/L [IQR 0.54-1.78] vs 0.22 10(9)/L [IQR 0.09-0.54] respectively, p < 0.0001). Total IgE was twice as high (264.5 kUI/l [IQR 166.3-779] vs 126 kUI/l [IQR 26-350] respectively; p < 0.05) and FeNO was nearly twice as high (61 [IQR 41-111] ppb vs 35 [IQR 23-51] ppb, p < 0.001). Allergic broncho-pulmonary aspergillosis (ABPA) and eosinophilic granulomatosis with polyangiitis (EGPA) were observed in the asthma patients with elevated serum IgG4. Ten patients had unexplained increased blood eosinophilia.

Conclusion: Asthma patients with elevated IgG4 levels have significantly higher blood eosinophilia, total IgE and FeNO. ABPA and EGPA are observed in patients with elevated serum IgG4.

Keywords: Allergic broncho-pulmonary aspergillosis; Asthma; Eosinophilic granulomatosis with polyangiitis; IgG4.

Publication types

  • Observational Study

MeSH terms

  • Adult
  • Aged
  • Aspergillosis, Allergic Bronchopulmonary / epidemiology
  • Aspergillosis, Allergic Bronchopulmonary / immunology*
  • Asthma / epidemiology
  • Asthma / immunology*
  • Asthma / physiopathology
  • Breath Tests
  • Churg-Strauss Syndrome / epidemiology
  • Churg-Strauss Syndrome / immunology*
  • Cohort Studies
  • Eosinophilia / epidemiology
  • Eosinophilia / immunology*
  • Female
  • Forced Expiratory Volume
  • Humans
  • Immunoglobulin E / immunology*
  • Immunoglobulin G / immunology*
  • Male
  • Middle Aged
  • Nitric Oxide / analysis
  • Retrospective Studies
  • Vital Capacity

Substances

  • Immunoglobulin G
  • Nitric Oxide
  • Immunoglobulin E