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Case Reports in Rheumatology
Volume 2012 (2012), Article ID 754935, 4 pages
http://dx.doi.org/10.1155/2012/754935
Case Report

IgG4-Related Disease without Overexpression of IgG4: Pathogenesis Implications

1Division of Rheumatology, Department of Internal Medicine, School of Medicine, Keio University, 35 Shinanomachi Shinjuku-ku, Tokyo 160-8582, Japan
2Division of Diagnostic Pathology, Keio University Hospital, Tokyo 160-8582, Japan

Received 3 April 2012; Accepted 10 July 2012

Academic Editors: L.-P. Erwig, M. Salazar-Paramo, and G. J. Tsay

Copyright © 2012 Naoshi Nishina 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

IgG4-related disease is a new disease group that affects multiple organs. It is characterized by high serum IgG4 and abundant infiltration of IgG4-bearing plasma cells in the affected organ. Here, we describe an intriguing case that suggested that IgG4-related disease might present without IgG4 overexpression or infiltration, at least during a relapse. A 47-year-old man had been diagnosed with systemic lupus erythematosus 15 years. He was admitted due to a pituitary mass, systemic lymphadenopathy, and multiple nodules in the lungs and kidneys. The serum IgG4 level was normal and histopathological examination of the pituitary mass showed abundant lymphocyte and plasma cell infiltration with very few IgG4-positive cells. When we examined specimens preserved from 15 years ago, we found high serum IgG4 levels and IgG4-bearing plasma cell infiltration. This resulted in a diagnosis of IgG4-related disease, and we considered the current episode to be a relapse without IgG4 overexpression. This case indicated that, to clarify the pathogenesis of IgG4-related disease, current cases should repeat specimen evaluations over the course of IgG4-related disease to define diagnostic markers.