Renal Phospholipase A2 Receptor in Hepatitis B Virus-Associated Membranous Nephropathy

Abstract

Objective: This study examined the expression of renal phospholipase A₂ receptor (PLA₂R) in idiopathic and secondary membranous nephropathy (MN). Methods: Patients with biopsy-proven MN and non-MN were enrolled. Renal PLA₂R was examined using an anti-PLA₂R antibody (anti-PLA₂R-Ab), and circulating PLA₂R-Ab was detected by indirect immunofluorescence. Results: Renal PLA₂R was detected along the capillary loop in 84% patients with idiopathic MN but not in those with any other primary glomerulonephritis. Only 1 of 38 patients with class V lupus nephritis showed renal PLA₂R positive. In hepatitis B virus-associated MN (HBV-MN), 64% showed renal PLA₂R positive, and PLA₂R overlapped with HBsAg along the capillary loop. In addition, renal PLA₂R positivity was closely associated with serum PLA₂R-Ab. Renal PLA₂R positive was present in all the patients with serum PLA₂R-Ab positive and in 53% of patients with serum PLA₂R-Ab negative. However, in patients with renal PLA₂R negative, serum PLA₂R-Ab was all negative. Conclusion: Renal biopsy PLA₂R positivity was common in idiopathic MN and HBV-MN but rare in lupus-associated MN, and it was closely associated with serum PLA₂R-Ab production. Further studies examining the association between PLA₂R and HBV-MN may shed light on the mechanism of idiopathic MN or HBV-MN.