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Published on: June 8, 2022
Anti-C1q antibodies and systemic lupus erythematosus in the Tunisian population
B Trad1, H Ben Hassine, M Khalifa
1Laboratory of Microbiology-Immunology, Farhat Hached Hospital, Ibn Al Jazzar street, 4000 Sousse, Tunisia.
Objectives:
The presence of a wide variety of autoantibodies is a characteristic feature of systemic lupus erythematosus (SLE). Although non-specific, anti-complement C1q (anti-C1q) were shown to correlate with the occurrence of active nephritis. The present study aimed to investigate the prevalence of anti-C1q in Tunisian SLE patients and their association with clinical manifestations, especially renal involvement.
Patients And Methods:
IgG anti-C1q antibodies were assessed by Elisa in 98 SLE patients, 55 patients with rheumatoid arthritis (RA) and 65 healthy individuals (HI).
Results:
Anti-C1q were found in 53 (54.1%) patients with SLE, three (5%) patients with RA and six (9.3%) HI. Among the 65 patients with renal involvement, anti-C1q were present in 35 (53.8%) patients. There was no significant association between anti-C1q and renal or extrarenal manifestations. In addition, there was no correlation between anti-C1q titer and SLEDAI index. Anti-C1q were significantly associated with anti-nucleosome (P=0.001), anti-Sm (P=0.01) and a low C4 level (P=0.046). Concomitant presence of anti-C1q and anti-dsDNA antibodies was not associated with renal manifestations.
Conclusion:
Our study shows that prevalence of anti-C1q was comparable with that previously reported in Caucasian populations. These antibodies were associated with a low C4 level. However, there was no association between anti-C1q and renal involvement or severity of nephritis.

