Clinical Value of Autoantibodies Against C1q in Children With Glomerulonephritis

• Published in: Pediatrics (Evanston) 2006-05, Vol.117 (5), p.1663-1668
• Main Authors: Kozyro, Ina, Perahud, Iryna, Sadallah, Salima, Sukalo, Alexander, Titov, Leonid, Schifferli, Jurg, Trendelenburg, Marten
• Format: Article
• Language: English
• Subjects: Adolescent; Arthritis, Juvenile - complications; Arthritis, Juvenile - immunology; Autoantibodies; Autoantibodies - blood; Autoimmune diseases; Biological and medical sciences; Biomarkers - blood; Child; Child, Preschool; Children & youth; Complement C1q - immunology; Complement C3 - analysis; Diagnosis; Drug therapy; Enzyme-Linked Immunosorbent Assay; Female; General aspects; Glomerulonephritis; Glomerulonephritis - diagnosis; Glomerulonephritis - immunology; Humans; Immune system; Kidney diseases; Lupus Nephritis - diagnosis; Lupus Nephritis - immunology; Male; Medical sciences; Nephrology. Urinary tract diseases; Nephropathies. Renovascular diseases. Renal failure; Pediatrics; Streptococcal Infections - complications; Streptococcal Infections - immunology
• ISSN: 0031-4005; 1098-4275
• DOI: 10.1542/peds.2005-1148

Autoantibodies against C1q (anti-C1q) have been found in a number of autoimmune and renal diseases. They are best described in adult patients with systemic lupus erythematosus, where a strong correlation between the occurrence of anti-C1q and severe lupus nephritis (LN) has been observed. However, the role of anti-C1q in children with systemic lupus erythematosus has not yet been determined. Furthermore, the clinical importance of anti-C1q in other forms of glomerulonephritis remains to be elucidated. The aim of this study was to investigate anti-C1q in children with different forms of glomerulonephritis including LN. We prospectively investigated 112 children with different forms of newly diagnosed glomerulonephritis for the presence of anti-C1q by an enzyme-linked immunosorbent assay and compared them with healthy controls. Associations between anti-C1q and disease manifestations at the time of the measurements and during follow-up were investigated. Twenty-one of 112 patients were positive for anti-C1q compared with 0 of 40 healthy controls. Anti-C1q was associated with activity in LN and with disease severity in patients with acute poststreptococcal glomerulonephritis (APSGN). In LN, 7 of 12 patients were found to be anti-C1q positive. Six of these 7 had active disease at the time of the serum sampling compared with 1 of 5 of the anti-C1q-negative children. In children with APSGN, 8 of 24 were positive for anti-C1q. Anti-C1q-positive APSGN patients had significantly higher proteinuria and more often hypertension than those without anti-C1q. All 4 patients in which APSGN did not resolve spontaneously were anti-C1q positive. Anti-C1q is associated with active LN in children. In addition, children with anti-C1q-positive APSGN have more severe disease than those who are anti-C1q negative. These data suggest APSGN is another disease in which anti-C1q has a pathogenic role.