RT Journal Article SR Electronic T1 IgG4 immune response in Churg–Strauss syndrome JF Annals of the Rheumatic Diseases JO Ann Rheum Dis FD BMJ Publishing Group Ltd and European League Against Rheumatism SP 390 OP 393 DO 10.1136/ard.2011.155382 VO 71 IS 3 A1 Augusto Vaglio A1 Johanna D Strehl A1 Bernhard Manger A1 Federica Maritati A1 Federico Alberici A1 Christian Beyer A1 Jürgen Rech A1 Renato A Sinico A1 Francesco Bonatti A1 Luisita Battistelli A1 Jörg H W Distler A1 Georg Schett A1 Jochen Zwerina YR 2012 UL http://ard.bmj.com/content/71/3/390.abstract AB Objective T-helper type 2 responses are crucial in Churg–Strauss syndrome (CSS) and may enhance the production of IgG4 antibodies. The authors assessed the IgG4 immune response in CSS patients. Methods The authors included 46 consecutive patients with CSS (24 with active and 22 with quiescent disease), 26 with granulomatosis with polyangiitis (GPA, Wegener's), 25 with atopic asthma and 20 healthy controls and determined serum IgG, IgM, IgA, IgE and IgG subclass levels. Tissue infiltration by IgG4 plasma cells was assessed in nine patients with CSS, 10 with GPA, 22 with chronic sinusitis (11 with and 11 without eosinophilia). Results IgG4 levels were markedly higher in active CSS patients than in controls (p<0.001 vs all control groups). Serum IgG4 correlated with the number of disease manifestations (r=0.52, p=0.01) and the Birmingham vasculitis activity score (r=0.64, p=0.001). Longitudinal analysis in 12 CSS cases showed that both the IgG4 level and IgG4/IgG ratio dropped during disease remission (p=3×10−5 and p=6×10−4, respectively). Tissue analysis did not show an increased IgG4 plasma cell infiltration in CSS biopsies compared with control groups. Conclusions Serum IgG4 levels are markedly elevated in active CSS and correlate with the number of organ manifestations and disease activity.