Increased IgG4 responses to multiple food and animal antigens indicate a polyclonal expansion and differentiation of pre-existing B cells in IgG4-related disease. Issue 5 (2nd February 2015)

• Record Type: Journal Article
• Authors: Culver, Emma L; Vermeulen, Ellen; Makuch, Mateusz; van Leeuwen, Astrid; Sadler, Ross; Cargill, Tamsin; Klenerman, Paul; Aalberse, Rob C; van Ham, S Marieke; Barnes, Eleanor; Rispens, Theo
• Is Part Of: Annals of the rheumatic diseases. Volume 74:Issue 5(2015)
• Page Start: 944
• Page End: 947
• Publication Date: 2015-02-02
• Subjects: B cells -- Inflammation -- Autoimmunity -- Corticosteroids; Rheumatism -- Periodicals; 616.723005
• DOI: 10.1136/annrheumdis-2014-206405
• Languages: English
• ISSNs: 0003-4967

Abstract

Abstract : Background: IgG4-related disease (IgG4-RD) is a systemic fibroinflammatory condition, characterised by an elevated serum IgG4 concentration and abundant IgG4-positive plasma cells in the involved organs. An important question is whether the elevated IgG4 response is causal or a reflection of immune-regulatory mechanisms of the disease. Objectives: To investigate if the IgG4 response in IgG4-RD represents a generalised polyclonal amplification by examining the response to common environmental antigens. Methods: Serum from 24 patients with IgG4-RD (14 treatment-naive, 10 treatment-experienced), 9 patients with primary sclerosing cholangitis and an elevated serum IgG4 (PSC-high IgG4), and 18 healthy controls were tested against egg white and yolk, milk, banana, cat, peanut, rice and wheat antigens by radioimmunoassay. Results: We demonstrated an elevated polyclonal IgG4 response to multiple antigens in patients with IgG4-RD and in PSC-high IgG4, compared with healthy controls. There was a strong correlation between serum IgG4 and antigen-specific responses. Responses to antigens were higher in treatment-naive compared with treatment-experienced patients with IgG4-RD. Serum electrophoresis and immunofixation demonstrated polyclonality. Conclusions: This is the first study to show enhanced levels of polyclonal IgG4 to multiple antigens in IgG4-RD. This supports that elevated IgG4 levels reflect an aberrant immunological regulation of the overall IgG4 response, but does not exclude that causality of disease could be antigen-driven.