title: Laser microdissection and proteomic analysis of amyloidosis, cryoglobulinemic GN, fibrillary GN, and immunotactoid glomerulopathy.
abstract: OBJECTIVE
  Organized deposits are present in amyloidosis, fibrillary GN, and immunotactoid glomerulopathy. However, the constituents of the deposits are not known.
  
  
  METHODS
  Laser microdissection of glomeruli followed by mass spectrometry was performed to determine the composition of the deposits. The results were compared with cryoglobulinemic GN.
  
  
  RESULTS
  The results are divided into four major groups: amyloidogenic proteins, structural/other proteins, complement proteins, and Igs. With regards to amyloidogenic proteins, large spectra numbers of apolipoprotein E are noted in amyloidosis (41.8±20.9) compared with fibrillary (15.6±12.5) and immunotactoid (12.3±12) glomerulopathy. Apolipoprotein E was absent in cryoglobulinemic GN. Serum amyloid P component is present in large spectra numbers in amyloidosis (14.1±6.7) and small spectra numbers in immunotactoid glomerulopathy, but it is absent in fibrillary and cryoglobulinemic GN. However, large spectra numbers of Ig γ-1 chain C region are present in immunotactoid glomerulopathy (47.3±34.6) compared with fibrillary (16.25±19.7) and cryoglobulinemic (13.3±4.9) GN. All cases of Ig light chain-associated amyloidosis showed spectra for the respective Ig light-chain C region (mean=10±1.7).
  
  
  CONCLUSIONS
  Based on the spectra numbers, the study shows that the relative amount of apolipoprotein E to Ig light-chain C region/amyloidogenic proteins or Ig γ-1 chain C region is associated with the organization of the deposits in amyloidosis, fibrillary GN, and immunotactoid glomerulopathy. However, the absence of apolipoprotein E correlates with the lack of fibrillar deposits in cryoglobulinemic GN.
authors: Division of Anatomic Pathology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota 55905, USA. sethi.sanjeev@mayo.edu
authors: Sanjeev
authors: S
authors: Sethi
authors: Jason D
authors: JD
authors: Theis
authors: Julie A
authors: JA
authors: Vrana
authors: Fernando C
authors: FC
authors: Fervenza
authors: Anjali
authors: A
authors: Sethi
authors: Qi
authors: Q
authors: Qian
authors: Patrick
authors: P
authors: Quint
authors: Nelson
authors: N
authors: Leung
authors: Ahmet
authors: A
authors: Dogan
authors: Samih H
authors: SH
authors: Nasr
mesh_terms: D000328:Adult; D000368:Aged; D058227:Amyloidogenic Proteins / Q000032:analysis; D000686:Amyloidosis / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D001057:Apolipoproteins E / Q000032:analysis; D015415:Biomarkers / Q000032:analysis; D001706:Biopsy; D003165:Complement System Proteins / Q000032:analysis; D003449:Cryoglobulinemia / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D005260:Female; D005921:Glomerulonephritis / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007136:Immunoglobulins / Q000032:analysis; D007678:Kidney Glomerulus / Q000737:chemistry* / Q000276:immunology / Q000648:ultrastructure; D061346:Laser Capture Microdissection; D008297:Male; D008875:Middle Aged; D011506:Proteins / Q000032:analysis*; D040901:Proteomics / Q000379:methods; D012189:Retrospective Studies; D053719:Tandem Mass Spectrometry
chemical_list: D058227:Amyloidogenic Proteins; D001057:Apolipoproteins E; D015415:Biomarkers; D007136:Immunoglobulins; D011506:Proteins; D003165:Complement System Proteins