title: Diagnosis of IgG4-related tubulointerstitial nephritis.
abstract: IgG4-related systemic disease is an autoimmune disease that was first recognized in the pancreas but also affects other organs. This disease may manifest as tubulointerstitial nephritis (IgG4-TIN), but its clinicopathologic features in the kidney are not well described. Of the 35 patients with IgG4-TIN whose renal tissue specimens we examined, 27 (77%) had acute or progressive chronic renal failure, 29 (83%) had involvement of other organ systems, and 18 of 23 (78%) had radiographic abnormalities. Elevated total IgG or IgG4 serum levels were present in 79%. All pathologic specimens featured plasma cell-rich TIN, with most showing diffuse, expansile interstitial fibrosis. Immune complexes along the tubular basement membranes were present in 25 of 30 (83%). All specimens had a moderate to marked increase in IgG4+ plasma cells by immunohistochemistry. We used a control group of 175 pathologic specimens with plasma cell-rich interstitial infiltrates that can mimic IgG4-TIN to examine the diagnostic utility of IgG4 immunostaining. Excluding pauci-immune necrotizing and crescentic glomerulonephritis, IgG4 immunohistochemistry had a sensitivity of 100% (95% CI 90-100%) and a specificity of 92% (95% CI 86-95%) for IgG4-TIN. Of the 19 patients with renal failure for whom treatment and follow-up data were available, 17 (89%) responded to prednisone. In summary, because no single test definitively diagnoses IgG4-related systemic disease, we rely on a combination of histologic, immunophenotypic, clinical, radiographic, and laboratory features. When the disease manifests in the kidney, our data support diagnostic criteria that can distinguish IgG4-TIN from other types of TIN.
authors: Division of Anatomic Pathology, Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 1 Street SW, Rochester, MN 55905, USA.
authors: Yassaman
authors: Y
authors: Raissian
authors: Samih H
authors: SH
authors: Nasr
authors: Christopher P
authors: CP
authors: Larsen
authors: Robert B
authors: RB
authors: Colvin
authors: Thomas C
authors: TC
authors: Smyrk
authors: Naoki
authors: N
authors: Takahashi
authors: Ami
authors: A
authors: Bhalodia
authors: Aliyah R
authors: AR
authors: Sohani
authors: Lizhi
authors: L
authors: Zhang
authors: Suresh
authors: S
authors: Chari
authors: Sanjeev
authors: S
authors: Sethi
authors: Mary E
authors: ME
authors: Fidler
authors: Lynn D
authors: LD
authors: Cornell
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D016130:Immunophenotyping; D007668:Kidney / Q000648:ultrastructure*; D008297:Male; D008875:Middle Aged; D009395:Nephritis, Interstitial / Q000175:diagnosis* / Q000276:immunology; D010950:Plasma Cells / Q000378:metabolism; D055815:Young Adult
chemical_list: D007074:Immunoglobulin G