title: Unusual IgM fibrillar deposits in glomerulonephritis: ultrastructural and diffraction studies in a case report.
abstract: Morphological examination of 2 renal biopsy specimens obtained from a 69-year-old woman with a nephrotic syndrome, high blood pressure, and a reduced glomerular filtration rate revealed, in ultrastructural study, a type of a glomerulonephritis with fibrillar deposits in a subendothelial position which were unusual in their immunoglobulin components (mainly IgM). The fibrillar components were of irregular size, 13 to 18 nm in diameter and presented a very particular "barbed wire" morphological aspect, not hitherto described. Diffraction studies and image analysis, revealed spiraled fibrils with regular alternating elements that we suggest may correspond to IgM molecules. The clinical (isolated renal symptoms) and laboratory (traces of 3 monoclonal components in the serum and 2 normal bone marrow biopsy specimens) data provided no evidence of hematopoietic malignancy, viral hepatitis or cryoglobulinemia.
authors.affiliation: INSERM U. 345, CHU Necker, Paris, France.
authors.forename: Bernadette
authors.initials: B
authors.lastname: Nabarra
authors.forename: Eric
authors.initials: E
authors.lastname: Larquet
authors.forename: Marie-Claue
authors.initials: MC
authors.lastname: Diemert
authors.forename: Veronique
authors.initials: V
authors.lastname: Leblond
authors.forename: Alain
authors.initials: A
authors.lastname: Baumelou
authors.forename: Helene
authors.initials: H
authors.lastname: Beaufils
mesh_terms: D000368:Aged; D005260:Female; D005921:Glomerulonephritis / Q000276:immunology / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007075:Immunoglobulin M / Q000648:ultrastructure*; D007678:Kidney Glomerulus / Q000473:pathology / Q000648:ultrastructure*; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D014961:X-Ray Diffraction
chemical_list: D007075:Immunoglobulin M