Serological diagnosis and prognosis of severe acute pancreatitis by analysis of serum glycoprotein 2

Background: Glycoprotein 2 (GP2), the pancreatic major zymogen granule membrane glycoprotein, was reported to be elevated in acute pancreatitis in animal models. Methods: Enzyme-linked immunosorbent assays (ELISAs) were developed to evaluate human glycoprotein 2 isoform alpha (GP2a) and total GP2 (GP2t) as specific markers for acute pancreatitis in sera of 153 patients with acute pancreatitis, 26 with chronic pancreatitis, 125 with pancreatic neoplasms, 324 with non-pancreatic neoplasms, 109 patients with liver/biliary disease, 67 with gastrointestinal disease, and 101 healthy subjects. GP2a and GP2t levels were correlated with procalcitonin and C-reactive protein in 152 and 146 follow-up samples of acute pancreatitis patients, respectively. Results: The GP2a ELISA revealed a significantly higher assay accuracy in contrast to the GP2t assay (sensitivity <= 3 disease days: 91.7%, specificity: 96.7%, positive likelihood ratio [LR+]: 24.6, LR-: 0.09). GP2a and GP2t levels as well as prevalences were significantly elevated in early acute pancreatitis (<= 3 disease days) compared to all control cohorts (p < 0.05, respectively). GP2a and GP2t levels were significantly higher in patients with severe acute pancreatitis at admission compared with mild cases (p < 0.05, respectively). Odds ratio for GP2a regarding mild vs. severe acute pancreatitis with lethal outcome was 7.8 on admission (p = 0.0222). GP2a and GP2t levels were significantly correlated with procalcitonin [Spearman's rank coefficient of correlation (rho) = 0.21, 0.26; p = 0.0110, 0.0012; respectively] and C-reactive protein (rho = 0.37, 0.40; p < 0.0001; respectively). Conclusions: Serum GP2a is a specific marker of acute pancreatitis and analysis of GP2a can aid in the differential diagnosis of acute upper abdominal pain and prognosis of severe acute pancreatitis.