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International Journal of Rheumatology
Volume 2012, Article ID 139409, 6 pages
http://dx.doi.org/10.1155/2012/139409
Clinical Study

IgG4-Related Disease Is Not Associated with Antibody to the Phospholipase A2 Receptor

1Department of Medicine, Harvard Medical School and Rheumatology Unit, Massachusetts General Hospital, Boston, MA 02114, USA
2Section of Nephrology, Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
3Department of Medicine, Harvard Medical School and The Division of Rheumatology, Allergy and Immunology and The Center for Immunology and Inflammatory Diseases of the General Medical Services, Massachusetts General Hospital, Boston, MA 02114, USA

Received 31 December 2011; Revised 6 February 2012; Accepted 20 February 2012

Academic Editor: Hisanori Umehara

Copyright © 2012 Arezou Khosroshahi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Patients with IgG4-related disease (IgG4-RD) share histopathological characteristics that are similar across affected organs. The finding of infiltration with IgG4+ plasma cells in the proper clinical and histopathological contexts connects a large number of clinical entities that were viewed previously as separate conditions. The renal involvement in IgG4-RD is usually characterized by tubulointerstitial nephritis, but membranous nephropathy has also been reported to be one of the renal complications of IgG4-RD. The recent discovery that a high proportion of patients with idiopathic membranous nephropathy (IMN) have IgG4 autoantibodies to the M-type phospholipase A2 receptor (PLA2R) in the circulation and glomerular immune deposits, together with the profound IgG4 hypergammaglobulinemia and occasional reports of membranous nephropathy in IgG4-RD, raised the question of a common antigen. To assess the presence of anti-PLA2R antibody in patients with IgG4-RD, we screened sera from 28 IgG4-RD patients by immunoblot. None of the patients in this cohort had detectable circulating anti-PLA2R antibodies. This study suggests that despite some clinical and serological overlaps between IgG4-RD and IMN,anti-PLA2R antibodies do not play a role in the pathogenesis of IgG4-RD. Additional studies of IgG4-RD with evidence of membranous nephropathy are important to exclude any definite relationship.