Etiology and clinical course of secondary membranous nephropathy.

Background : Membranous nephropathy (MN) is the most common cause of adult nephrotic syndrome worldwide. Although MN is commonly idiopathic, there are some secondary causes. In this article we describe the clinical courses of the patients with MN presumedly due to secondary causes. Methods : Fifty-one patients with MN were retrospectively evaluated for possible etiologic factors as well as evaluated for their clinical courses after renal biopsy between March 1990 and December 2003 in the Dong-a University College of Medicine. Results : There were 19 men and 32 women (M:F=1:1.6). The majority of the causes of secondary MN were SLE (31 cases, 60.8%) & hepatitis B (12 cases, 23.5%). The others included malignancy, hepatitis C, syphilis and MCTD. Twenty-nine of 31 cases with SLE which were treated with prednisolone and cyclophosphamide and 25 cases (86.4%) showed complete remission (CR) or partial remission (PR). Three of 12 cases associated with hepatitis B (HB) were treated with prednisolone over 6 months and showed CR or PR. Three of other 12 cases associated with HB which showed positivity to HBsAg & HBeAg were treated with interferon- and represented complete seroconversion of HBeAg, but rapidly progressed to chronic renal failure. Conclusion : In our study, the most common causes of secondary MN are SLE, HB. HBeAg may be the important predictor in the prognosis of HBV-associated MN. The effect of interferon- therapy in treating secondary MN is as yet inconclusive. HBV-associated MN progresses rapidly to CRF, therefore more extended study is required in Korea, an endemic area of HB.