A Case of IgG4-Related Disease Manifesting as Extensive Abdominal Periarteritis and Membranous Nephropathy, Successfully Controlled with Low-Dose Steroid Therapy without Relapse or Complications

Abstract

Introduction: IgG4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory disease that can affect nearly every organ system, including blood vessels and the kidney. IgG4-related vascular lesions mainly involve the aorta, and the dominant renal manifestation is tubulointerstitial nephritis (TIN). Here, we report a case of IgG4-RD demonstrating extensive abdominal periarteritis and membranous nephropathy (MN).

Case presentation: The patient was a 71-year-old man with peptic ulcer who developed nephrotic syndrome, with a low serum albumin level (1.8 g/dL), massive urinary protein (6.1 g/day), and high serum IgG4 level (435 mg/dL). Computed tomography images revealed soft tissue mass around the medium-sized abdominal arteries. Renal pathological findings showed MN and focal infiltration of numerous IgG4-positive cells in the interstitium. The findings of high serum IgG4 levels, periarteritis, and focal inflammation with rich IgG4-positive plasma cells led to the diagnosis of IgG4-RD. We chose low-dose steroid therapy to prevent the recurrence of the peptic ulcer and aneurysm formation in the affected arteries, which can occur with medium to high doses of prednisolone. We successfully controlled IgG4-related periarteritis and kidney disease without relapse or complications.

Conclusion: The varied clinical manifestations of IgG4-RD sometimes make the diagnosis challenging. However, clinicians should diagnose IgG4-RD based on serological, radiological, and pathological evaluations because, without appropriate therapy, IgG4-RD can lead to irreversible organ failure caused by swelling, obstruction, or fibrosis of the organs.

Keywords: IgG4-related disease; IgG4-related kidney disease; Membranous nephropathy; Periarteritis.

Fig. 1.

CT findings. Soft tissue mass around the superior mesenteric artery (SMA) (a) and inferior mesenteric artery (IMA) (b) was observed (arrows). c, d The mass was slightly enhanced in the delayed phase (circle). The CT values of soft tissue mass in arterial phase and delayed phase images were 58 HU and 74 HU, respectively.

Fig. 2.

Renal histological findings. a Twenty percent of the interstitium showed fibrosis. Infiltration of inflammatory cells was observed only focally in the interstitium (hematoxylin-eosin stain). b Spike formation was detected on the glomerular basement membrane (GBM) (a Periodic acid-methenamine-silver stain). c–e Inflammatory cells composed of lymphocytes and plasma cells were dispersed in the interstitium. The IgG4/IgG-positive plasma cell ratio was 76%, and the number of IgG4-positive plasma cells was 71/high-power field. b Hematoxylin-eosin stain. c IgG stain. d IgG4 stain. f–i Immunostaining for the IgG subclass showed that IgG1 deposition along the capillary walls was dominant, IgG4 deposition was second dominant, and staining for IgG2 and IgG3 was very weak. j Electron microscopy showed subepithelial deposits along the GBM, consistent with stage Ⅱ MN. a Bars = 500 μm. b–e Bars = 100 μm. f–i Bars = 50 μm. j Bars = 2 μm.

Fig. 3.

Clinical course.

Fig. 4.

a–c Improvement of the soft tissue mass lesions. Contrast-enhanced CT revealed that the soft tissue mass was reduced by 25% 12 months after initiating treatment with a low-dose steroid.