A Case of Membranoproliferative Glomerulonephritis with False-Positive Reaction for Anti-GBM Antibody

Korean Journal of Nephrology 2009;28(5):480-484.

Kyoung Suk Park, M.D.1., Seun Duk Hwang, M.D.1, Byung Soo Jeon, M.D.1, Jin Yi Choi, M.D.1, Ji Sun Song, M.D.2, Soo Young Yoon, M.D.1 and Sang Choel Lee, M.D.1

Department of Internal Medicine¹
Pathology²
College of Medicine, Kwandong University, Goyang, Korea

증례 : 혈청 항기저막 항체검사에서 위양성을 보인 막증식성 사구체신염 1예

박경석1, 황선덕1, 전병수1, 최진이1, 송지선2, 윤수영1, 이상철1

관동대학교 의과대학 내과학교실1, 병리학교실2

Abstract

Anti-glomerular basement membrane (Anti-GBM) nephritis is an autoimmune disorder characterized by rapidly progressive crescentic glomerulonephritis (RPGN). The treatment of anti-GBM nephritis with plasmapheresis, steroids and immunosuppressant has improved outcomes. An early diagnosis is essential for the survival of patients and a recovery of renal function. The diagnosis of anti-GBM disease has been traditionally based on the demonstration of linear deposits of immunoglobulins along the glomerular basement membrane by immunofluorescence (IF) microscopy. However, a kidney biopsy cannot always be easily performed in such ill patients. Recent development of specific enzyme immunoassays for anti-GBM antibody in the serum has made possible a provisional diagnosis without a kidney biopsy. A 46-year-old male patient with hypertension and hepatitis B presented with generalized edema and general weakness. Laboratory findings were compatible with acute renal failure and nephrotic syndrome with positive serum anti-GBM antibodies. After plasmapheresis with steroid pulse therapy, renal biopsy was performed and diagnosed as membranoproliferative glomerulonephritis (MPGN) with granular deposit of Ig G and C3. Follow-up antibody titers were negative. This case demonstrates the possibility of false-positive anti-GBM antibody in the serum. Therefore, enzyme immunoassay for anti-GBM antibody should be used only as a screening or follow-up test in patients that have been confirmed positive by IF microscopy.

Key Words: Antiglomerular basement membrane antibody, false positive reactions, Membranoproliferative glomerulo