Background Silent lupus nephritis is defined by some pathological evidence of lupus nephritis with normal urinary findings. It is therefore apparent only upon renal biopsy. Serum complement levels have been associated with overall lupus disease activity. Despite recent progress in understanding the pathogenesis of lupus nephritis, including complement, our understanding of silent lupus nephritis, especially in children, remains limited.
Objectives To search whether serum complement levels are associated with renal pathological classification in children with silent lupus nephritis.
Methods We determined serum C3 and C4 levels and International Society of Nephrology/Renal Pathology Society classification in 25 patients with paediatric silent lupus nephritis before initial therapy who were admitted to our hospital. Patients were classified as having silent lupus nephritis based on normal urinary findings at baseline renal biopsy in juvenile systemic lupus erythematosus.
Results Serum C3 levels varied between International Society of Nephrology/Renal Pathology Society classes, with significantly lower levels for silent lupus nephritis patients in class III compared to class II, and for class II compared to class I. There was no significant difference in serum C4 levels between International Society of Nephrology/Renal Pathology Society classes in patients with silent lupus nephritis.
Conclusions Our results suggest that serum C3 levels were associated with renal pathological classification in children with silent lupus nephritis. We propose that serum C3 levels would provide a useful tool for predicting latent severe nephritis in patients with juvenile systemic lupus erythematosus who have normal urinary findings before initial therapy.
Disclosure of Interest None declared