Clinicopathological Features of Membranous Nephropathy Complicated by IgA Nephropathy: A Retrospective Analysis of Seven Cases

Aims/Background Both membranous nephropathy (MN) and immunoglobulin A nephropathy (IgAN) are immune complex-mediated glomerular diseases, but the concurrent occurrence of these two conditions in the same patient is not common, a phenomenon that is currently not supported by clinical data in terms of treatment and prognosis. This study explores the clinical and pathological characteristics, as well as the treatment outcomes, of patients affected by MN and IgAN simultaneously. Methods The clinical data, pathological features, and diagnostic and therapeutic information of seven cases of MN complicated by IgAN, treated between December 2015 and December 2022, were retrospectively analyzed. Results Among the seven cases, there were two male and five female patients, with an average age of 57.3 +/- 9.2 years. All patients presented with clinical manifestations of proteinuria and edema upon admission, with an average 24-hour urine protein of 3716.6 +/- 1519.4 mg/24 h. Phospholipase A2 receptor (PLA2R) expression was detected in all seven cases, and nephrotic syndrome was clinically diagnosed in five cases. Additionally, all seven cases showed microscopic hematuria, with intermittent gross hematuria in two cases. All seven patients included in this study underwent renal biopsy. After disease staging, the patients had MN stages I-III and IgAN stages II-III. Pathological findings revealed abnormal glomerular basement membrane (GBM) and diffuse immunoglobulin G (IgG) deposition in the subepithelial space, predominantly of the IgG4 subtype. Simultaneously, there was diffuse mesangial zone deposition of immunoglobulin A (IgA) to varying degrees, co-localization of complement component C3 and IgA, and mesangial cell proliferation. Treatment strategies included angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) in combination with steroids or immunosuppressive therapies such as tacrolimus, cyclophosphamide, and rituximab. After 2-6 months of treatment, all patients achieved complete remission with a favourable prognosis. Conclusion MN accompanied by IgAN tends to occur more frequently in middle-aged and elderly individuals, with a relatively low incidence. The latent feature of the comorbidities manifests as a form of IgAN superimposed on the background of MN. Utilizing ACEI or ARB in combination with steroids or various immunosuppressive therapies represents a potentially effective treatment strategy.