Membranous Nephropathy

Abstract

Membranous nephropathy (MN) is a glomerular disease that is the leading cause of nephrotic syndrome in non-diabetic Caucasian adults. MN is most often primary (idiopathic) and the remaining is secondary to systemic disease or exposure to infection or drugs. The majority of patients with MN have circulating antibodies to the podocyte antigens phospholipase A 2 receptor (PLA2R) (70%) and thrombospondin type-1 domain-containing 7A (THSD7A) (3-5%). Immunologic remission (depletion of PLA2R antibodies) often precedes and may predict clinical remission. Untreated, about one-third of patients undergo spontaneous remission, one-third have persistent proteinuria but maintain kidney function and the remaining one-third will develop end stage kidney failure. All patients with idiopathic MN should be treated with conservative care from the time of diagnosis to minimise proteinuria. Immunosuppressive therapy is traditionally reserved for patients who have persistent nephrotic-range proteinuria despite conservative care. Immunosuppressive agents for primary MN include combination of corticosteroids/ alkylating agent or calcineurin inhibitors and rituximab. This chapter will review the epidemiology, diagnosis and treatment of MN, particularly focusing on idiopathic MN. light microscopy. However, with time, the glomerular basement membrane thickens and there is formation of subepithelial "spikes" of basement membrane on the outer surface of the capillary wall. These "spikes" are more apparent with silver methenamine staining (Figure 1). Immunofluorescence microscopy reveals diffuse, uniform, finely granular deposits of IgG4 along the outer surfaces of capillary walls (Figure 2). Complement components, including C3, C4d and C5b-9, are also DOI: http://dx.