title: Tubulointerstitial immune complex nephritis in a patient with systemic lupus erythematosus: role of peritubular capillaritis with immune complex deposits in the pathogenesis of the tubulointerstitial nephritis.
abstract: Class IV-G (A/C) diffuse lupus nephritis and tubulointerstitial (TI) nephritis in a 31-year old woman was studied by light, immunofluorescence (IF), and electron microscopy (EM), to determine the pathogenesis of the TI lesions. The light microscopic findings showed peritubular capillaritis in the interstitium, with ruptures in the capillary structure, lysis of the surrounding tubular basement membrane (TBM), extravasated red blood cells (RBCs), the infiltration of neutrophils and mononuclear cells, and edema. The IF study revealed IgG, IgA, IgM, C1q, C3, and C4 depositions along the TBM, on the capillary walls, and in the interstitium proper. The EM study disclosed the deposition of immune complexes in the TBM, the capillary wall, and the interstitium proper. Based on these findings, the TI nephritis in this patient was considered to be due to peritubular capillaritis secondary to the immune complex depositions in the capillary wall of the interstitium.
authors.affiliation: First Department of Internal Medicine, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo 181-0086, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hayakawa
authors.forename: Kimimasa
authors.initials: K
authors.lastname: Nakabayashi
authors.forename: Miho
authors.initials: M
authors.lastname: Karube
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Arimura
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Arimura
authors.forename: Akinori
authors.initials: A
authors.lastname: Soejima
authors.forename: Akira
authors.initials: A
authors.lastname: Yamada
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Fujioka
mesh_terms: D000328:Adult; D000936:Antigen-Antibody Complex / Q000032:analysis; D001485:Basement Membrane / Q000737:chemistry; D001706:Biopsy; D002196:Capillaries / Q000737:chemistry / Q000473:pathology; D005260:Female; D006801:Humans; D007684:Kidney Tubules / Q000098:blood supply; D008180:Lupus Erythematosus, Systemic / Q000150:complications* / Q000473:pathology; D008775:Methylprednisolone / Q000627:therapeutic use; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D009395:Nephritis, Interstitial / Q000209:etiology* / Q000473:pathology; D011239:Prednisolone / Q000627:therapeutic use; D020551:Pulse Therapy, Drug
chemical_list: D000936:Antigen-Antibody Complex; D011239:Prednisolone; D008775:Methylprednisolone