Abstract

A 69-year-old man presented with acute kidney injury, hypocomplementemia, antinuclear antibody, and anti-dsDNA antibody. He had no signs of systemic lupus erythematosus or Sjögren syndrome. He had not begun taking any new drugs in the preceding 6 months. Kidney biopsy revealed 13 glomeruli, 3 with global sclerosis. The remaining glomeruli showed slight mesangial proliferation. The interstitial inflammation was extensive, comprising mainly mature lymphocytes and plasma cells, neutrophils, and a few eosinophils. Remarkable granular and diffuse deposition of IgG and C1q was observed along the tubular basement membranes. Electron microscopy showed electron-dense deposits in the tubular basement membrane. Immunohistochemistry showed only 1 – 4 IgG4-positive plasma cells per high-power field and an IgG4/CD138 ratio of ~ 10%. He was treated with oral prednisolone 35 mg/day, and his kidney function gradually improved. This is a unique case that is not consistent with any known disease entities with immune complex-mediated tubulointerstitial nephritis.


Author Details

Authors

• Haruka Ikuta¹
• Jaegi Shim¹
• Masahiro Takahashi¹
• Mitsuteru Koizumi¹
• Koichi Seta¹
• Shigeo Hara²
• Kensei Yahata¹

Departments

• ¹ Department of Nephrology, National Hospital Organization Kyoto Medical Center, Kyoto, and
• ² Department of Diagnostic Pathology, Kobe University Graduate School of Medicine, Hyogo, Japan

Address

Kensei Yahata, MD
Department of Nephrology
National Hospital Organization Kyoto Medical Center
1-1 Fukakusa Mukaihata-cho, Fushimi-ku, Kyoto 612-8555, Japan

Email: kenseiyahata@
yahoo.co.jp

Citation