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

Non-pancreatic hyperlipasemia: A puzzling clinical entity

BACKGROUND

Increased lipase level is a serological hallmark of the diagnosis of acute pancreatitis (AP) but can be detected in various other diseases associated with lipase leakage due to inflammation of organs surrounding the pancreas or reduced renal clearance and/or hepatic metabolism. This non-pancreatic hyperlipasemia (NPHL) is puzzling for attending physicians during the diagnostic procedure for AP. It would be clinically beneficial to identify the clinical and laboratory variables that hinder the accuracy of lipase diagnosis with the aim of improve it. A more precise description of the NPHL condition could potentially provide prognostic factors for adverse outcomes which is currently lacking.

AIM

To perform a detailed clinical and laboratory characterization of NPHL in a large prospective patient cohort with an assessment of parameters determining disease outcomes.

METHODS

A Hungarian patient cohort with serum lipase levels at least three times higher than the upper limit of normal (ULN) was prospectively evaluated over 31 months. Patients were identified using daily electronic laboratory reports developed to support an ongoing observational, multicenter, prospective cohort study called the EASY trial (ISRCTN10525246) to establish a simple, easy, and accurate clinical scoring system for early prognostication of AP. Diagnosis of NPHL was established based on ≥ 3 × ULN serum lipase level in the absence of abdominal pain or abdominal imaging results characteristic of pancreatitis.

RESULTS

A total of 808 patients [male, n = 420 (52%); median age (IQR): 65 (51-75) years] were diagnosed with ≥ 3 × ULN serum lipase levels. A total of 392 patients had AP, whereas 401 had NPHL with more than 20 different etiologies. Sepsis and acute kidney injury (AKI) were the most prevalent etiologies of NPHL (27.7% and 33.2%, respectively). The best discriminative cut-off value for lipase was ≥ 666 U/L (sensitivity, 71.4%; specificity, 88.8%). The presence of AKI or sepsis negatively affected the diagnostic performance of lipase. NPHL was associated with a higher in-hospital mortality than AP (22.4% vs 5.1%, P < 0.001). In multivariate binary logistic regression, not lipase but increased amylase level (> 244 U/L) and neutrophil-to-lymphocyte ratio (NLR) (> 10.37, OR: 3.71, 95%CI: 2.006-6.863, P < 0.001), decreased albumin level, age, and presence of sepsis were independent risk factors for in-hospital mortality in NPHL.

CONCLUSION

NPHL is a common cause of lipase elevation and is associated with high mortality rates. Increased NLR value was associated with the highest mortality risk. The presence of sepsis/AKI significantly deteriorates the serological differentiation of AP from NPHL.

Antibodies Against Glycoprotein 2 Are Specific Biomarkers for Pediatric Crohn's Disease

BACKGROUND

Serological markers can assist in accurate differentiation between Crohn's disease (CD) and ulcerative colitis (UC). One such marker is anti-glycoprotein 2 (anti-GP2) which was shown to be a specific marker for CD in adult patients. The aim of our study was to assess the utility of anti-GP2 and GP2 as biomarkers for pediatric CD, and determine whether they correlate with disease activity.

METHODS

Serum samples were tested by ELISA for anti-GP2 isoform 4 IgG and IgA, and also for GP2. Results were correlated with demographic and clinical data.

RESULTS

The cohort consisted of 53 pediatric patients with CD, 42 with UC, and 53 controls. Levels of anti-GP2 were significantly increased in pediatric patients with CD in comparison with patients with UC, and control subjects, with high positive predictive value for both IgG and IgA (97.9% and 82.6%, respectively). While specificity of anti-GP2 IgG and IgA was very high (98.7% and 90.0%, respectively), sensitivity was low (42.0% and 35.5% for IgG and IgA, respectively). In CD, anti-GP2 correlated with disease activity, and decreased in treatment-naïve patients following successful induction therapy. A higher IgA anti-GP2 was also demonstrated in patients with ileo-colonic involvement, and was associated with a younger age. Finally, positive GP2 level was identified in only 1/211 serum samples.

CONCLUSIONS

A positive anti-GP2 level is highly associated with CD, while a negative result does not exclude CD. Additional studies are required to determine whether these markers can be used in pediatric patients with CD for risk stratification.

Serum glycoprotein 2 as a biomarker of severity of acute pancreatitis

BACKGROUND

Acute pancreatitis (AP) is a main cause of acute abdominal pain. Although the pathophysiology of AP is not fully understood, it is now widely acknowledged that the activation of enzymes in zymogen granules (ZGs) plays an important role in the progression of AP. In AP animal models, the up-regulation of serum ZG glycoprotein 2 (GP2) can be used as a potential biological marker for AP.

AIM

To investigate whether serum GP2 can be used as an early biomarker of AP severity.

METHODS

In a prospective single-center cohort study, plasma samples and baseline clinical data were collected from 9 healthy subjects and 59 patients with AP within 24 h of onset. Serum GP2 levels were detected by enzyme-linked immunosorbent assay, and their correlation with the severity of AP was analyzed.

RESULTS

Of the 59 AP patients, 30 had mild AP, 16 had moderate AP, and 13 had severe AP. Serum GP2 levels were significantly increased in AP patients and positively correlated with AP severity. Using 2.3 ng/mL as the cut-off point, the sensitivity and specificity of serum GP2 to distinguish moderate AP were 96.6% and 90.0%, respectively, and the positive and negative predictive values were 90.3% and 96.4%, respectively. Using 5.1 ng/mL as the cut-off point, the sensitivity, specificity, positive predictive value, and negative predictive value to distinguish severe AP were all 100%. Serum GP2 was found to be a better prognostic marker than bedside index for severity in acute pancreatitis score, hematocrit, admission or persistent systemic inflammatory response score, and C-reactive protein.

CONCLUSION

Serum GP2 increases in AP patients, and it positively correlates with the severity of AP, suggesting its potential to predict the severity of AP.