jkra The Journal of the Korean Rheumatism Association J Korean Rheum Assoc 1226-8070 2233-4718 The Korean Rheumatism Association 10.4078/jkra.2010.17.4.393 jkra-17-393 Original Article Clinical Significance of Serum C1q-Circulating Immune Complexes in Patients with Lupus Nephritis KimJuyoun 1 KimSang-Hyon 1 KimHae-Rim 2 ParkSung-Hwan 3 Division of Rheumatology, Department of Internal Medicine, Keimyung University School of Medicine, Seoul, Korea Daegu, Konkuk University School of Medicine, Seoul, Korea The Catholic University of Korea College of Medicine, Seoul, Korea 122010 23122010 17 4 393 399 25082010 23112010 26112010 Copyright © 2010 The Korean Rheumatism Association 2010 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Objective

The purpose of this study was to evaluate whether serum C1q-circulating immune complexes (C1q-CIC) serve as a predictive marker for renal flares in patients with lupus nephritis.

 Methods

Twenty-five patients with lupus nephritis and 24 healthy controls were enrolled. Patients with lupus nephritis had their serum C1q-CIC titers and other serologic parameters such as serum C3, C4, anti-dsDNA antibody, and erythrocyte sedimentation rate measured simultaneously. The systemic lupus erythematosus disease activity index (SLEDAI) was also checked.

 Results

Serum C1q-CIC titers were higher in patients with lupus nephritis than in healthy controls (109.33±53.79 μg/mL vs. 75.28±22.91 μg/mL, p=0.008). A statistically significant association was found between serum C1q-CIC titers and C3 (p=0.011), C4 (p=0.027), and anti-dsDNA antibody (p=0.014). SLEDAI was also correlated with serum C1q-CIC titers (p=0.022).

 Conclusion

Serum C1q-CIC appears to be related to renal disease activity in patients with lupus nephritis. These results suggest that serum C1q-CIC is a predictive marker for renal flares in patients with lupus nephritis.

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Serum levels of C1q-circulating immune complexes (C1g-CIC) in healthy controls and patients with lupus nephritis (p=0.008).

Correlations between serum C1q-circulating immune compleses (C1q) level and C3 (A), C4 (B), anti-ds DNA antibody (C), and the systemic lupus erythematosus disease activity index (SLEDAI) (D) were observed in patients with lupus nephritis.

Baseline clinical characteristics of the study patients

Sex (female) 24 (96%)
Age
Age at diagnosis of SLE 23.5±7.6 years
Age at diagnosis of lupus nephritis 36.6±10.0 years
Renal histology
Patients undergo renal biopsy 17 (68%)
WHO classification III : 2 (8%), IV:9 (36%), V:6 (24%)
Activity index 5.5
Chronicity index 3.5
Extrarenal involvement
Malar rash 13 (52%)
Arthritis 12 (48%)
Leukopenia 9 (36%)
Hemolytic anemia 7 (28%)
Serositis 6 (24%)
Thrombocytopenia 6 (24%)
Central nervous system 5 (20%)
Pneumonitis 2 (8%)
Vasculitis 2 (8%)
Myocarditis 2 (8%)
Pulmonary hypertension 1 (4%)