Vol.22 No.3

Original Article

Value of serum IgG4 in the diagnosis of IgG4-related disease and in differentiation from rheumatic diseases and other diseases

Authors

Motohisa Yamamoto1 , Tetsuya Tabeya1 , Yasuyoshi Naishiro1 , Hidetaka Yajima1 , Keisuke Ishigami1 , Yui Shimizu1 , Mikiko Obara1 , Chisako Suzuki1 , Kentaro Yamashita1 , Hiroyuki Yamamoto1 , Toshiaki Hayashi1 , Shigeru Sasaki1, Toshiaki Sugaya1, Tadao Ishida1, Ken-ichi Takano2, Tetsuo Himi2, Yasuo Suzuki3, Norihiro Nishimoto4, Saho Honda5, Hiroki Takahashi1, Kohzoh Imai1,6, Yasuhisa Shinomura1

  • First Department of Internal Medicine, Sapporo Medical University School of Medicine, South 1-West 16, Chuo-ku, Sapporo, Hokkaido, 0608543, Japan
  • Department of Otolaryngology, Sapporo Medical University School of Medicine, Sapporo, Japan
  • Department of Ophthalmology, Teine Keijinkai Hospital, Sapporo, Japan
  • Laboratory of Immune Regulation, Wakayama Medical University, Osaka, Japan
  • Department of Internal Medicine and Rheumatology, JR Sapporo Hospital, Sapporo, Japan
  • Advanced Clinical Research Center, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
Received:

4 July 2011

Accepted:

31 August 2011

Published online:

28 September 2011

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Abstract

IgG4-related disease (IgG4-RD) is a novel disease entity that includes Mikulicz’s disease, autoimmune pancreatitis (AIP), and many other conditions. It is characterized by elevated serum IgG4 levels and abundant IgG4-bearing plasmacyte infiltration of involved organs. We postulated that high levels of serum IgG4 would comprise a useful diagnostic tool, but little information is available about IgG4 in conditions other than IgG4-RD, including rheumatic diseases. Several reports have described cutoff values for serum IgG4 when diagnosing IgG4-RD, but these studies mostly used 135 mg/dL in AIP to differentiate from pancreatic cancer instead of rheumatic and other common diseases. There is no evidence for a cutoff serum IgG4 level of 135 mg/dL for rheumatic diseases and common diseases that are often complicated with rheumatic diseases. The aim of this work was to re-evaluate the usual cutoff serum IgG4 value in AIP (135 mg/dL) that is used to diagnose whole IgG4-RD in the setting of a rheumatic clinic by measuring serum IgG4 levels in IgG4-RD and various disorders. We therefore constructed ROC curves of serum IgG4 levels in 418 patients who attended Sapporo Medical University Hospital due to IgG4-RD and various rheumatic and common disorders. The optimal cutoff value of serum IgG4 for a diagnosis of IgG4-RD was 144 mg/dL, and the sensitivity and specificity were 95.10 and 90.76%, respectively. Levels of serum IgG4 were elevated in IgG4-RD, Churg?Strauss syndrome, multicentric Castleman’s disease, eosinophilic disorders, and in some patients with rheumatoid arthritis, systemic sclerosis, chronic hepatitis, and liver cirrhosis. The usual cut-off value of 135 mg/dL in AIP is useful for diagnosing whole IgG4-RD, but high levels of serum IgG4 are sometimes observed in not only IgG4-RD but also other rheumatic and common diseases.

Key words

Autoimmune pancreatitis - Churg-Strauss syndrome - IgG4 - Mikulicz’s disease - Rheumatoid arthritis