Detection and clinical significance of glomerular M-type phospholipase A2 receptor in patients with idiopathic membranous nephropathy.

BACKGROUND: Glomerular M-type phospholipase A2 receptor (PLA2 R) is important for diagnosing idiopathic membranous nephropathy (IMN). The relation between glomerular PLA2 R expression and response to treatment remains to be explored.

AIMS: We conducted the study to explore the positive rate and clinical significance of glomerular M-type PLA2 R in IMN patients.

METHODS: A total of 122 IMN patients receiving neither glucocorticoid nor immunosuppressant therapy prior to renal biopsies was included and followed for more than 1 year. The control group comprised 30 patients with secondary membranous nephropathy and 100 patients with non-membranous forms of nephropathy. PLA2 R level and IgG subclasses in glomeruli were detected. The primary end-point was the reduction of proteinuria to less than 50% of baseline value.

RESULTS: A total of 82.0% of patients with IMN had positive glomerular PLA2 R deposits, compared with 16.7% in the secondary membranous nephropathy group (P < 0.001). Additionally, PLA2 R-positive expression combined with IgG4 ≥ 2+ was found in 94.3% IMN patients, compared with 40.0% in secondary membranous nephropathy patients (P < 0.01). Among IMN patients, the remission rate of proteinuria after either glucocorticoid or glucocorticoid combined immunosuppressant therapy for at least 6 months was 83.9% in the PLA2 R-positive group compared with 54.5% in the negative group (P < 0.05).

CONCLUSION: The positive rate of glomerular PLA2 R was more prevalent in IMN patients. Both PLA2 R and IgG4 glomerular deposits may help in discriminating between idiopathic and secondary membranous nephropathy. IMN patients with positive PLA2 R expression probably have a more beneficial response to glucocorticoid and/or immunosuppressant therapy.