title: Specific immunoassay reveals increased serum trypsinogen 3 in acute pancreatitis.
abstract: BACKGROUND
  Trypsinogen 3 is a minor trypsinogen isoform in the pancreas. In contrast with trypsin 1 and 2, trypsin 3 degrades pancreatic secretory trypsin inhibitor, which may lead to an excess of active trypsin and acute pancreatitis (AP). We developed an immunoassay for trypsinogen 3 and studied whether an assay of serum trypsinogen 3 is of clinical utility in the diagnosis of AP.
  
  
  METHODS
  Monoclonal antibodies were generated using recombinant human trypsinogen 3 as the antigen and used to establish a sandwich-type immunoassay. We analyzed serum trypsinogen 3 concentrations in 82 patients with AP and 63 patients with upper abdominal pain (controls). The reference interval was determined using serum samples from 172 apparently healthy individuals.
  
  
  RESULTS
  The measuring range of the trypsinogen 3 assay was 1.0-250 μg/L. Intra- and interassay CVs were <11%, and cross-reactivity with other trypsinogen isoenzymes was <0.1%. The median trypsinogen 3 concentration in serum from healthy individuals was <1.0 μg/L, and the upper reference limit was 4.4 μg/L. We observed increased trypsinogen 3 concentrations in patients with mild (median 9.5 μg/L) and severe (15.0 μg/L) AP; in both groups, the concentrations were significantly higher than in controls (median <1.0 μg/L) (P < 0.0001). In ROC analysis, the area under the curve of trypsinogen 3 for separation between AP and controls was 0.90 (P < 0.0001).
  
  
  CONCLUSIONS
  We established for the first time a specific immunoassay for trypsinogen 3 using monoclonal antibodies. Patients with AP were found to have increased serum concentrations of trypsinogen 3. The availability of this assay will be useful for studies of the clinical utility of trypsinogen 3.
authors.affiliation: Department of Surgery, Helsinki University,Central Hospital, Finland.
authors.forename: Jani
authors.initials: J
authors.lastname: Oiva
authors.forename: Outi
authors.initials: O
authors.lastname: Itkonen
authors.forename: Riitta
authors.initials: R
authors.lastname: Koistinen
authors.forename: Kristina
authors.initials: K
authors.lastname: Hotakainen
authors.forename: Wang-Ming
authors.initials: WM
authors.lastname: Zhang
authors.forename: Esko
authors.initials: E
authors.lastname: Kemppainen
authors.forename: Pauli
authors.initials: P
authors.lastname: Puolakkainen
authors.forename: Leena
authors.initials: L
authors.lastname: Kylänpää
authors.forename: Ulf-Håkan
authors.initials: UH
authors.lastname: Stenman
authors.forename: Hannu
authors.initials: H
authors.lastname: Koistinen
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007527:Isoenzymes / Q000097:blood; D008297:Male; D008875:Middle Aged; D010195:Pancreatitis / Q000097:blood*; D019283:Pancreatitis, Acute Necrotizing / Q000097:blood; D012016:Reference Values; D012680:Sensitivity and Specificity; D014357:Trypsin / Q000097:blood*; D055815:Young Adult
chemical_list: D000911:Antibodies, Monoclonal; D015415:Biomarkers; D007527:Isoenzymes; C040749:PRSS3 protein, human; D014357:Trypsin