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Mediators of Inflammation
Volume 2016 (2016), Article ID 2196986, 7 pages
http://dx.doi.org/10.1155/2016/2196986
Research Article

Association between IgG4 Autoantibody and Complement Abnormalities in Systemic Lupus Erythematosus

Institute of Nephrology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, China

Received 1 April 2016; Accepted 13 July 2016

Academic Editor: Tinatin Chikovani

Copyright © 2016 Qingjun Pan 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

In order to investigate the association between IgG4 autoantibody and complement abnormalities in systemic lupus erythematosus (SLE), 72 newly diagnosed SLE patients, 67 rheumatoid arthritis (RA) patients, and 41 healthy normals were employed. Serum levels of antinuclear IgG4 and IgG4-specific IgM-rheumatoid factor (RF) were measured, and the correlations between serum levels of antinuclear IgG4 and several clinical parameters were analyzed. Also, the levels of IgG subclasses, C1q, and C3 deposition in lupus nephritis (LN) were detected. The results showed that serum levels of antinuclear IgG4 were higher in SLE patients relative to healthy normals (). Serum levels of antinuclear IgG4 in SLE patients were positively correlated with serum levels of total IgG4, albumin, and C3 (, ; , ; and , , resp.) and negatively correlated with 24-hour urinary protein (, ). Serum levels of IgG4-specific IgM-RF were higher in RA patients than in SLE patients (). Also, the ratio of the deposition score for IgG4/(IgG1 + IgG2 + IgG3 + IgG4) was negatively correlated with the score for C1q and C3 deposition in LN (, ; , , resp.). In summary, the IgG4 autoantibody may dampen the inflammatory response in SLE, thus maybe providing a novel therapeutic target for SLE.