Association between IgG4 Autoantibody and Complement Abnormalities in Systemic Lupus Erythematosus.
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 (P < 0.01). Serum levels of antinuclear IgG4 in SLE patients were positively correlated with serum levels of total IgG4, albumin, and C3 (r = 0.61, P < 0.05; r = 0.40, P < 0.05; and r = 0.54, P < 0.05, resp.) and negatively correlated with 24-hour urinary protein (r = 0.49, P < 0.05). Serum levels of IgG4-specific IgM-RF were higher in RA patients than in SLE patients (P < 0.001). 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 (r = 0.34, P < 0.05; r = 0.51, P < 0.01, resp.). In summary, the IgG4 autoantibody may dampen the inflammatory response in SLE, thus maybe providing a novel therapeutic target for SLE.
Institute of Nephrology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, China.
Qingjun
0000-0002-8060-9099
Q
Pan
Institute of Nephrology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, China.
Linjie
L
Guo
Institute of Nephrology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, China.
Jing
J
Wu
Institute of Nephrology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, China.
Jun
0000-0002-7347-1407
J
Cai
Institute of Nephrology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, China.
Huanjin
H
Liao
Institute of Nephrology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, China.
Qiaofen
Q
Lan
Institute of Nephrology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, China.
Yanxia
Y
Peng
Institute of Nephrology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, China.
Yiming
Y
He
Institute of Nephrology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, China.
Hua-Feng
0000-0001-6547-212X
HF
Liu
D000293:Adolescent; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D002648:Child; D015922:Complement C1q / Q000378:metabolism; D003176:Complement C3 / Q000378:metabolism; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D008180:Lupus Erythematosus, Systemic / Q000097:blood* / Q000276:immunology; D008181:Lupus Nephritis / Q000097:blood; D008297:Male; D008875:Middle Aged; D012709:Serum Albumin / Q000378:metabolism; D055815:Young Adult
D001323:Autoantibodies; D003176:Complement C3; D007074:Immunoglobulin G; D012709:Serum Albumin; D015922:Complement C1q