Early initiation of immunosuppressive treatment in membranous nephropathy patients

Membranous nephropathy: Mechanistic insights and therapeutic perspectives

Membranous nephropathy (MN) is one of the most common causes of non-diabetic nephrotic syndrome in adults. About 80% of cases are renal limited (primary MN) and 20% are associated with other systemic diseases or exposures (secondary MN). Autoimmune reaction is the main pathogenic factor of MN, and the discovery of autoantigens including the phospholipase A2 receptor and thrombospondin type-1 domain-containing protein 7A has led to new insights into the pathogenesis, they can induce humoral immune responses led by IgG4 makes them suitable for the diagnosis and monitoring of MN. In addition, complement activation, genetic susceptibility genes and environmental pollution are also involved in MN immune response. In clinical practice, due to the spontaneous remission of MN, the combination of supportive therapy and pharmacological treatment is widely used. Immunosuppressive drugs are the cornerstone of MN treatment, and the dangers and benefits of this approach vary from person to person. In summary, this review provides a more comprehensive review of the immune pathogenesis, interventions and unresolved issues of MN in the hope of providing some new ideas for clinical and scientific researchers in the treatment of MN.

Urine anti-PLA2R antibody is a novel biomarker of idiopathic membranous nephropathy

Since urine samples more directly reflect kidney alterations and damage than blood samples, we investigated whether urine anti-PLA₂R antibody (uPLA₂R-Ab) could be utilized similarly to serum anti-PLA₂R antibody (sPLA₂R-Ab) as a noninvasive biomarker of idiopathic membranous nephropathy (IMN). In this study, we performed a qualitative analysis using an indirect immunofluorescence test (IIFT) and measured uPLA₂R-Ab and sPLA₂R-Ab concentrations using an enzyme-linked immunosorbent assay (ELISA) in 28 patients with biopsy-proven IMN and 12 patients with secondary membranous nephropathy (SMN). Overall, 64.3% (n=18) of patients with IMN had IIFT-positive sPLA₂R-Ab, 67.9% (n=19) of patients with IMN had IIFT-positive uPLA₂R-Ab, and none of the SMN patients had IIFT-positive sPLA₂R-Ab or uPLA₂R-Ab. The titers of the anti-PLA₂R antibody from the IMN patients in the urine (10.72±22.24 RU/μmol, presented as uPLA₂R-Ab/urine creatinine) and serum (107.36±140.93 RU/ml) were higher than those from the SMN patients (0.51±0.46 RU/μmol, 0.008±0.029 RU/ml, respectively, p<0.05). Statistical analyses indicated that there were positive correlations between uPLA₂R-Ab and gPLA₂R, sPLA₂R-Ab or urinary protein and negative correlations between uPLA₂R-Ab and serum albumin in patients with IMN. In conclusion, uPLA₂R-Ab is a novel biomarker of IMN. sPLA₂R-Ab combined with uPLA₂R-Ab might be more helpful for diagnosis and activity in PLA₂R associated MN.