title: Anti-C1q antibodies and their association with complement components in Indian systemic lupus erythematosus patients.
abstract: Systemic lupus erythematosus (SLE) is a prototype autoimmune disease, characterized by immune complex formation and systemic inflammation. Complement components such as C1q and mannose-binding lectin (MBL) play an important role in the clearance of immune complexes. Anti-C1q antibodies are associated with lupus nephritis and reduced levels of the complement components. The objective of this study was to detect anti-C1q antibodies in SLE patients and to evaluate their association with the complement components. Sixty SLE patients were included, of whom 75% had lupus nephritis (LN) and 25% were without renal manifestations (non-LN). The disease activity was assessed at the time of evaluation by the systemic lupus erythematosus disease activity index (SLEDAI). Anti-C1q antibodies, circulating immune complexes, and serum MBL levels were detected by enzyme-linked immunosorbent assay. The anti-C1q antibody prevalence was 58.3%. The LN patients showed 60% anti-C1q positivity with a higher percentage in membranoproliferative glomerulonephritis patients (51.9%). Anti-dsDNA positivity was slightly higher among the anti-C1q positives than in the anti-C1q negatives (65.7% vs. 60%). A higher percentage of reduced C3 and C4 levels was noted among the anti-C1q positives. The LN patients showed a higher percentage of low MBL levels among anti-C1q negatives than in the anti-C1q positives (61.1% vs. 55.6%). Non-LN patients showed a higher percentage of low MBL levels among anti-C1q positives than among anti-C1q negatives (87.5% vs. 57.1%). Anti-C1q antibodies were found in both LN and non-LN patients, but there was no correlation with the clinical severity of the disease.
authors: Department of Autoimmune Disorders, National Institute of Immunohematology, Indian Council of Medical Research, Mumbai, India.
authors: V
authors: V
authors: Pradhan
authors: A
authors: A
authors: Rajadhyaksha
authors: G
authors: G
authors: Mahant
authors: P
authors: P
authors: Surve
authors: M
authors: M
authors: Patwardhan
authors: S
authors: S
authors: Dighe
authors: K
authors: K
authors: Ghosh
keywords: Anti-C1q antibodies; C3; C4; SLE without nephritis (non-LN); lupus nephritis; mannose-binding lectin; systemic lupus erythematosus