title: Diagnostic performance of amyloid A protein quantification in fat tissue of patients with clinical AA amyloidosis.
abstract: OBJECTIVE
  Amyloid A protein quantification in fat tissue is a new immunochemical method for detecting AA amyloidosis, a rare but serious disease. The objective was to assess diagnostic performance in clinical AA amyloidosis.
  
  
  METHODS
  Abdominal subcutaneous fat tissue of patients with AA amyloidosis was studied at the start of an international clinical trial with eprodisate (NC-503; 1,3-propanedisulfonate; Kiacta), an antiamyloid compound. All patients had renal findings, i.e. proteinuria (> or =1 g/day) or reduced creatinine clearance (20 - 60 ml/min). Controls were patients with other types of amyloidosis and arthritic patients without amyloidosis. Amyloid A protein was quantified by ELISA using monoclonal antihuman serum amyloid A antibodies. Congo red stained slides were scored by light microscopy in a semiquantitative way (0 to 4+).
  
  
  RESULTS
  Ample fat tissue (>50 mg) was available for analysis in 154 of 183 patients with AA amyloidosis and in 354 controls. The sensitivity of amyloid A protein quantification for detection of AA amyloidosis (>11.6 ng/mg fat tissue) was 84% (95% CI: 77 - 89%) and specificity 99% (95% CI: 98 - 100%). Amyloid A protein quantification and semiquantitative Congo red scoring were concordant. Men had lower amyloid A protein values than women (p < 0.0001) and patients with familial Mediterranean fever had lower values than patients with arthritis (p < 0.001) or other inflammatory diseases (p < 0.01).
  
  
  CONCLUSIONS
  Amyloid A protein quantification in fat tissue is a sensitive and specific method for detection of clinical AA amyloidosis. Advantages are independence from staining quality and observer experience, direct confirmation of amyloid AA type, and potential for quantitative monitoring of tissue amyloid over time.
authors.affiliation: Department of Rheumatology and Clinical Immunology, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands. b.p.c.hazenberg@int.umcg.nl
authors.forename: Bouke P C
authors.initials: BP
authors.lastname: Hazenberg
authors.forename: Johan
authors.initials: J
authors.lastname: Bijzet
authors.forename: Pieter C
authors.initials: PC
authors.lastname: Limburg
authors.forename: Martha
authors.initials: M
authors.lastname: Skinner
authors.forename: Philip N
authors.initials: PN
authors.lastname: Hawkins
authors.forename: Irena
authors.initials: I
authors.lastname: Butrimiene
authors.forename: Avi
authors.initials: A
authors.lastname: Livneh
authors.forename: Olga
authors.initials: O
authors.lastname: Lesnyak
authors.forename: Evgeney L
authors.initials: EL
authors.lastname: Nasonov
authors.forename: Anna
authors.initials: A
authors.lastname: Filipowicz-Sosnowska
authors.forename: Ahmet
authors.initials: A
authors.lastname: Gül
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Merlini
authors.forename: Piotr
authors.initials: P
authors.lastname: Wiland
authors.forename: Huri
authors.initials: H
authors.lastname: Ozdogan
authors.forename: Peter D
authors.initials: PD
authors.lastname: Gorevic
authors.forename: Hédi Ben
authors.initials: HB
authors.lastname: Maïz
authors.forename: Merrill D
authors.initials: MD
authors.lastname: Benson
authors.forename: Haner
authors.initials: H
authors.lastname: Direskeneli
authors.forename: Kalevi
authors.initials: K
authors.lastname: Kaarela
authors.forename: Denis
authors.initials: D
authors.lastname: Garceau
authors.forename: Wendy
authors.initials: W
authors.lastname: Hauck
authors.forename: Martin H
authors.initials: MH
authors.lastname: Van Rijswijk
mesh_terms: D050153:Abdominal Fat / Q000737:chemistry*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000686:Amyloidosis / Q000145:classification / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism*; D016022:Case-Control Studies; D003224:Congo Red; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011407:Propane / Q000031:analogs & derivatives / Q000627:therapeutic use; D000685:Serum Amyloid A Protein / Q000032:analysis*; D013451:Sulfonic Acids / Q000627:therapeutic use
chemical_list: D000685:Serum Amyloid A Protein; D013451:Sulfonic Acids; D003224:Congo Red; C520274:eprodisate; D011407:Propane