M-Type Phospholipase A2 Receptor Staining in Children with Idiopathic Membranous Nephropathy: PLA2R Staining in Children with IMN

Abstract

Background: Membranous Nephropathy (MN) is a common cause of nephrotic syndrome in adults that can also occur in children, albeit less frequently. Recently, the M-type phospholipase A2 receptor (PLA2R) was identified as the target antigen in idiopathic membranous nephropathy (IMN), making it a useful marker for diagnosis. However, there are few studies describing the potential role of PLA2R in children with IMN. The aim of this study was to clarify the involvement of PLA2R in childhood IMN. Methods: We enrolled 11 patients diagnosed with IMN from January 1998 to March 2017. We performed PLA2R staining in paraffin-embedded renal biopsy sections. The clinical data were collected from the patients’ medical records. Results: The median age at biopsy was 6 years (range, 4 to 14 years). A single 6-year-old boy among all pediatric patients with IMN had granular PLA2R staining along his glomerular capillary loops and the prevalence of PLA2R-positivity was 9%. He also showed IgG4 co-dominant staining in terms of IgG subclass. There were no apparent differences in his clinical features such as clinical data at the time of renal biopsy, the time from the treatment initiation to remission, and relapse or renal dysfunction during the follow-up period. Conclusion: We suggest that PLA2R staining can be a diagnostic tool for patients with IMN of any age, though pediatric patients with IMN have lower prevalence of PLA2R-positive staining than adult patients.