Kidney Week

Abstract: TH-PO682

A Case of Membranous Nephropathy Secondary to ANCA-Associated Vasculitis

Session Information

• Glomerular Diseases: Case Reports - 1
  October 24, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Aizawa, Chiharu, Sei Roka Kokusai Byoin, Chuo-ku, Tokyo, Japan

Chiharu Aizawa, MD

• Fujimaru, Takuya, Sei Roka Kokusai Byoin, Chuo-ku, Tokyo, Japan

Takuya Fujimaru, MD, PhD

• Iwata, Futoshi, Sei Roka Kokusai Byoin, Chuo-ku, Tokyo, Japan

Futoshi Iwata, MD

• Kadota, Nozomi, Sei Roka Kokusai Byoin, Chuo-ku, Tokyo, Japan

Nozomi Kadota, MD

• Ishikawa, Risa, Sei Roka Kokusai Byoin, Chuo-ku, Tokyo, Japan

Risa Ishikawa, MD

• Ito, Yugo, Sei Roka Kokusai Byoin, Chuo-ku, Tokyo, Japan

Yugo Ito, MD, PhD

• Nagahama, Masahiko, Sei Roka Kokusai Byoin, Chuo-ku, Tokyo, Japan

Masahiko Nagahama, MD, FASN

• Taki, Fumika, Sei Roka Kokusai Byoin, Chuo-ku, Tokyo, Japan

Fumika Taki, MD, PhD, FASN

• Chiga, Motoko, Tokyo Ika Shika Daigaku, Bunkyo-ku, Tokyo, Japan

Motoko Chiga

• Sohara, Eisei, Tokyo Ika Shika Daigaku, Bunkyo-ku, Tokyo, Japan

Eisei Sohara, MD, PhD

• Uchida, Shinichi, Tokyo Ika Shika Daigaku, Bunkyo-ku, Tokyo, Japan

Shinichi Uchida, MD, PhD

• Suzuki, Michiko, Sei Roka Kokusai Byoin, Chuo-ku, Tokyo, Japan

Michiko Suzuki, MD, PhD

Introduction

ANCA-associated vasculitis (AAV) is sometimes associated with secondary membranous nephropathy (MN). Avacopan, a complement C5a receptor inhibitor, is a drug that can minimize or discontinue corticosteroid doses for AAV. It is unclear whether avacopan, which exerts anti-inflammatory effects through selective C5a receptor antagonism, is useful in the treatment of secondary MN due to AAV.

Case Description

An 80-year-old woman had tested positive for anti-Mycobacterium avium complex antibodies 6 years earlier. She was followed up without treatment because she had no respiratory symptoms. She had been P-ANCA positive for 3 years, but there were no findings suggestive of vasculitis and she was followed up without treatment. She presented to our department with increasing serum creatinine from 0.6 mg/dL to 1.2 mg/dL, severe proteinuria (10 g/gCr), hematuria, and hypoalbuminemia (Alb 2.3 g/dL). Clinically, she was diagnosed with rapid progressive glomerulonephritis with nephrotic syndrome. A renal biopsy was performed and revealed findings of necrotizing crescentic nephritis and MN. Immunofluorescence (IF) staining showed positive IgG4 and MPO-ANCA in the glomerular basement membrane (GBM) but negative anti-PLA2R and anti-THSD7A antibodies. We diagnosed AAV and secondary MN due to MPO-ANCA. We started treatment with prednisolone, rituximab, and avacopan. Prednisolone decreased early. Serum P-ANCA became negative after 1 month of treatment. Seven months later, serum creatinine improved to 1.0 mg/dL, urine protein was 2.8 g/g Cr and serum Alb was 3.9 g/dL.

Discussion

Secondary MN associated with AAV often shows positive MPO-ANCA in the GBM and is negative for IgG4 and anti-PLA2R antibodies in IF staining. However, there have been several case reports of IgG4 predominance. In this case, MPO-ANCA was positive for GBM and was considered secondary MN due to AAV. Avacopan in combination with rituximab and early dose reduction of prednisolone resulted in resolution of P-ANCA, improvement of renal dysfunction, and resolution of proteinuria in this patient. Steroid-sparing therapy with avacopan and rituximab may be effective in secondary MN due to ANCA.