title: The clinicopathologic characteristics and outcome of atypical anti-glomerular basement membrane nephritis.
abstract: Classic anti-glomerular basement membrane (GBM) disease presents with rapidly progressive glomerulonephritis (GN) with or without pulmonary hemorrhage. On biopsy typical disease displays bright polytypic linear GBM staining for IgG by immunofluorescence and diffuse crescentic/necrotizing GN on light microscopy. Here, we studied 20 patients with atypical anti-GBM nephritis typified by bright linear GBM staining for immunoglobulins but without a diffuse crescentic phenotype. Patients had hematuria, proteinuria, and mild renal insufficiency, without pulmonary hemorrhage. Light microscopy showed endocapillary proliferative GN in 9 patients, mesangial proliferative GN in 6, membranoproliferative GN in 3, and focal segmental glomerulosclerosis with mesangial hypercellularity in 2. Eight of the 20 showed features of microangiopathy. Crescents/necrosis were absent in 12 and were focal in 8 patients. Bright linear GBM staining for IgG was seen in 17 patients, IgM in 2, and IgA in 1 patient, which was polytypic in 10 patients and monotypic in 10 patients. No circulating α3NC1 antibodies were detected by commercial ELISA. The 1-year patient and renal survival rates were 93% and 85%, respectively. Thus, atypical anti-GBM nephritis is a rare variant of anti-GBM disease characterized clinically by an indolent course, no pulmonary involvement, and undetectable circulating α3NC1 antibodies. Further studies are needed to characterize the molecular architecture of GBM autoantigens in these patients and establish optimal therapy.
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Samih H
authors.initials: SH
authors.lastname: Nasr
authors.affiliation: Pathology Service, Massachusetts General Hospital, Boston, Massachusetts, USA.
authors.forename: A Bernard
authors.initials: AB
authors.lastname: Collins
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Mariam Priya
authors.initials: MP
authors.lastname: Alexander
authors.affiliation: Department of Pathology and Laboratory Medicine, Gundersen Health System, La Crosse, Wisconsin, USA.
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Schraith
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Loren
authors.initials: L
authors.lastname: Herrera Hernandez
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Fidler
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Sethi
authors.affiliation: Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Nelson
authors.initials: N
authors.lastname: Leung
authors.affiliation: Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Fernando C
authors.initials: FC
authors.lastname: Fervenza
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA. Electronic address: cornell.lynn@mayo.edu.
authors.forename: Lynn D
authors.initials: LD
authors.lastname: Cornell
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019867:Anti-Glomerular Basement Membrane Disease / Q000473:pathology*; D001706:Biopsy; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007668:Kidney / Q000473:pathology* / Q000648:ultrastructure; D008297:Male; D008875:Middle Aged; D055815:Young Adult
keywords: anti-GBM disease; glomerulonephritis; kidney biopsy; nephrotic syndrome; renal pathology