Lupus Membranous Nephropathy

Abstract

Background: Lupus membranous nephropathy (LMN) is a rare disease, usually associated with nephrotic syndrome. Methods: We reviewed the literature by searching for the following terms on Pubmed.gov: lupus nephritis, membranous nephropathy (MN), lupus membranous nephropathy, nephrotic syndrome, and Class V lupus nephritis. Results: The histology of LMN at light microscopy is similar to that of primary MN. Cases of MN associated with focal or diffuse proliferation are not considered LMN by the International Society of Nephrology/Renal Pathology Society classification. Immunofluorescence study of LMN shows deposits of all immunoglobulins and complement. Tubulo-reticular structures, extraglomerular deposits, subepithelial, and scanty subendothelial deposits can be seen on electron microscopy. Phospholipase A2 receptor deposits are usually but not necessarily absent in LMN. The pathogenesis is still not completely understood. The inflammatory milieu of lupus may favor the development of autoantigens and intraglomerular assembly of immune complexes. These are more often associated with mesangial or endocapillary hypercellular lesions. Alternatively, autoantibodies may bind autoantigens in the glomerular subepithelium, triggering a signaling cascade leading to LMN. A central role in the development of podocyte injury and proteinuria is played by the components of complement C5b-C9. CKD progression in LMN is slow but may be accelerated by the frequency of renal flares. Persistent nephrotic syndrome and/or the frequent use of corticosteroids may lead to a series of life-threatening complications. Discussion: Treatment of arterial hypertension, dyslipidemia, and diabetes are of paramount importance. Besides specific therapies of these complications, hydroxychloroquine and vitamin D supplementation are recommended. Immunosuppression should be limited to patients with nephrotic proteinuria. The most frequently used drugs are corticosteroids, calcineurin inhibitors, cyclophosphamide, mycophenolate, and rituximab, alone or combined. Early detection and treatment of renal flares is of paramount importance to prevent CKD progression.