Clinical presentation and outcomes of childhood-onset membranous lupus nephritis

Background Best practices for managing childhood-onset membranous lupus nephritis (MLN) are not yet established. Most studies involve primarily or exclusively adult cohorts or pediatric cohorts with combinations of pure or mixed membranous and proliferative nephritis. Methods We performed a single-center cohort study of consecutively diagnosed children with pure MLN from 1990 and 2016. Patients received care in Houston, Texas, one of the most diverse metropolitan areas in North America. Renal outcomes were obtained using consensus definitions from the Childhood Arthritis and Rheumatology Research Alliance (CARRA). Logistic regression was used to detect predictors of complete renal response. Results A total of 56 children with MLN were identified (82% females, 44% black, 35% Hispanic) with a median follow-up time of 4.1 years. The mean age of MLN onset was 13.7 ± 3.4 years. On initial presentation 69% had nephrotic syndrome and 11% had acute kidney injury. Glucocorticoids were prescribed in 96% of patients and anti-malarials in 88%. Mycophenolate mofetil was the most common non-steroid immunosuppressive agent (69%), followed by rituximab (25%), cyclophosphamide (18%), and azathioprine (9%). Renin–angiotensin aldosterone system blocking agents were prescribed in 78% of patients. Of 37 patients with ≥2 years of follow-up, 74% achieved complete renal response at 24 months. No predictor variable of complete renal response was identified in this small cohort. Renal flares occurred in 48% of patients (86% proteinuric, 14% nephritic). On subsequent renal biopsy, 13% patients had developed proliferative nephritis. Conclusions This single-center cohort of childhood-onset MLN showed favorable outcomes. Utilizing pediatric renal outcomes definitions, we found that response rates were high, as were rates of renal flare.