RESUMO
Abstract Introduction: Anti-nucleosome and anti-C1q antibodies demonstrated an association with the development of glomerulonephritis in systemic lupus erythematosus (SLE). Some investigators have proposed that monitoring anti- C1q and anti-nucleosome antibodies might be valuable for making predictions about lupus nephritis (LN) and assessment of disease activity as a non-invasive biological marker of renal disease. Objectives: The current study was proposed to investigate the presence of anti-C1q and anti-nucleosome antibodies in the sera of Egyptian patients with SLE and their association with LN. Methods: Eighty patients with SLE were included. Patients were classified into, a LN group including 40 cases with active LN (based on the results of renal biopsy and renal SLEDAI≥4) and a non renal SLE group including 40 patients (with no clinical or laboratory evidence of renal involvement that were attributed in the past or present to SLE). They were subjected to full medical history taking, clinical examination, routine laboratory investigations, measurement of antinuclear antibody (ANA), anti-ds DNA, anti-C1q & anti-nucleosome antibodies. Results: Anti-C1q antibody showed a statistically significant association with the presence of vasculitis and nephritis while anti-nucleosome antibody didn't show a significant association with the presence of any clinical features. Double positivity of anti-nucleosome and anti-C1q antibodies showed a statistically significant association with the presence of vasculitis and photosensitivity, high ECLAM score, elevated ESR, low serum albumin and low C3 levels. Conclusion: Serum anti-C1q antibody has a significant association with LN while double positive antibodies have a significant association with vasculitis and low C3 levels in Egyptian patients with SLE.