Nephrotic syndrome in mesangial proliferative lupus nephritis

Renal involvement is a major complication of systemic lupus erythematosus (SLE) and occurs in 30-70% of patients with SLE. Lupus nephritis is classified into six classes (I-VI) by the International Society of Nephrology and Renal Pathology Society (ISN/RPS). Although nephrotic syndrome is commonly associated with diffuse (ISN/RPS class IV) or membranous (ISN/RPS class V) lupus nephritis, several reports have described nephrotic syndrome in adult patients with minimal mesangial lupus nephritis (ISN/RPS class I) or mesangial proliferative lupus nephritis (ISN/RPS class II). However, nephrotic syndrome in mesangial proliferative lupus nephritis has rarely been reported in children. Although the pathogenesis of nephrotic syndrome with mesangial lupus nephritis is incompletely understood, three potential mechanisms have been postulated including lupus nephritis itself, non-steroidal anti inflammatory drug (NSAID)-induced minimal change nephrotic syndrome (MCNS) and coincidental occurrence of MCNS. We describe here a child with mesangial proliferative lupus nephritis who developed MCNS.