Abstract: Ｏｂｊｅｃｔｉｖｅ：To investigate the clinic pathological characteristics and outcomes of patients with phospholipase A2 receptor (PLA2R)-positive Class V lupus nephritis (LN).
Ｍｅｔｈｏｄｏｌｏｇｙ：From 2009 to 2022, all biopsy-proven class V LN cases at the National Clinical Research Centre of Kidney Diseases were screened for glomerular PLA2R and exostosin(EXT). Serum anti-PLA2R antibodies were measured by ELISA (positivity≥2 RU/mL). All patients received standard immunosuppressive therapy. A retrospective analysis was conducted on the clinical and pathological features, treatment responses, and prognoses of patients with PLA2R-positive Class V LN.
Ｒｅｓｕｌｔｓ：Among 214 class V LN cases, 8 (3.74 %) showed glomerular PLA2R positivity. Seven patients were women (87.5 %); median age at onset was 38 years. All presented with nephrotic syndrome or nephrotic-range proteinuria (median 24-h protein 4.40 g), and one had concurrent acute kidney injury. Anti-dsDNA antibodies were negative in all; seven patients were anti-SSA positive. Five patients had serum anti-PLA2R testing: median titer 12.97 RU/mL; only one exceeded 20 RU/mL, the rest were low-titer (2-20 RU/mL). Biopsies revealed granular PLA2R deposits along the glomerular basement membrane, mixed immunoglobulin/complement deposition, mesangial electron-dense deposits in four cases, and concomitant EXT positivity in one. Median time to renal remission was 5 months. At remission, anti-PLA2R antibodies became undetectable except for one patient with persistent low-titer positivity. Over 17-143 months of follow-up, all patients experienced renal relapse (1-3 episodes each), yet final renal function remained preserved.
Ｃｏｎｃｌｕｓｉｏｎ：A small proportion of class V LN is PLA2R-related. These patients tend to be older, exhibit low-titer anti-PLA2R titers, and have a high relapse rate. Enhanced monitoring of anti-PLA2R and reinforced maintenance therapy may help lower relapse risks.

Key words: phospholipase A2 receptor, lupus nephritis, membranous nephropathy