From the Guidelines
PLA2R is a crucial biomarker in diagnosing and monitoring primary membranous nephropathy (PMN), and its antibody levels correlate with disease activity, predicting response to treatment and risk of relapse. The presence of anti-PLA2R antibodies is a valuable diagnostic tool to distinguish primary from secondary forms of the disease, with about 70-80% of patients with primary membranous nephropathy testing positive 1. Testing for PLA2R antibodies can be done through blood tests or kidney biopsy tissue staining, and positive results strongly suggest primary membranous nephropathy rather than secondary causes.
Key Points
- PLA2R antibody levels can predict changes in proteinuria and disease prognosis, with decreasing levels often preceding clinical remission 1
- The trajectory of anti-PLA2R antibody levels over time is more important than a single measurement in determining disease prognosis and treatment response 1
- Monitoring PLA2R antibody levels can guide treatment decisions, with persistent or rising levels indicating potential treatment resistance 1
- The use of PLA2R antibody levels in conjunction with other clinical parameters, such as eGFR and proteinuria, can help stratify patients into different risk categories and guide treatment decisions 1
Treatment Implications
- Patients with low-risk disease may be managed with a "wait and see" approach, while those with moderate to high-risk disease may require immunosuppressive therapy, such as rituximab or cyclophosphamide 1
- The choice of treatment should be guided by the patient's individual risk profile, as well as their response to therapy, with adjustments made based on changes in PLA2R antibody levels and clinical parameters 1
From the Research
PLA2R-Associated Membranous Nephropathy
- PLA2R-associated membranous nephropathy is a common cause of nephrotic syndrome in adults, characterized by the presence of autoantibodies against the phospholipase A2 receptor (PLA2R) 2, 3.
- The disease can be primary or secondary, with secondary forms often associated with malignancy, infection, or autoimmune disease 4.
Treatment with Rituximab
- Rituximab, a B-cell depleting agent, has emerged as a safe and effective treatment for PLA2R-associated membranous nephropathy, inducing remission in approximately two-thirds of treated patients 2, 5, 3, 6.
- The treatment regimen typically consists of weekly infusions of rituximab, with the possibility of repeated courses to achieve immunological remission 2, 5.
- Rituximab has been shown to be effective in patients with stage 4 or 5 chronic kidney disease, as well as in those with malignancy-associated membranous nephropathy 2, 5.
Predictive Factors and Outcomes
- The urinary albumin-to-protein ratio before treatment has been identified as a predictive factor of renal response to rituximab 2.
- Immunological remission, characterized by the depletion of anti-PLA2R autoantibodies, is associated with a good clinical outcome and can be used as a biomarker to predict response to treatment 3.
- Patients who achieve complete or partial remission after rituximab treatment tend to have stable renal function and improved clinical parameters, such as reduced proteinuria and increased serum albumin levels 2, 5.