Fecal pyruvate kinase is not suitable for discrimination between inflammatory bowel disease exacerbation and acute gastroenteritis.

INTRODUCTION: In inflammatory bowel diseases (IBD) diarrhea can be caused by exacerbation and/or infectious agents. Fecal calprotectin (FC) is a well-established biomarker of intestinal inflammation in IBD. However, its usefulness in depiction of IBD exacerbation from infectious diarrhea is limited. The value of fecal pyruvate kinase isoenzyme type 2 (M2-PK) in this application remains unknown. AIM: To compare the performance of M2-PK and FC in discriminating between diarrhea caused by IBD and infectious agents. MATERIALS AND METHODS: One hundred three patients were enrolled for the study, including 32 with ulcerative colitis (UC), 21 with Crohn's disease (CD), 29 with acute diarrhea caused by rotavirus (AD-RV), and 21 with acute diarrhea caused by Salmonella enteritidis (AD-SE). M2-PK and FC were measured using ELISA. Areas under receiver operating characteristic curves (AUCs), sensitivities and specificities for both tests in distinguishing between patient subgroups with moderate to severe UC and CD from AD-RV and AD-SE were calculated. RESULTS: Differences in AUCs between M2-PK and FC for distinguishing UC [CD] from AD-RV were -0.06 (p < 0.028) [-0.10 (p < 0.0018)] and for differentiating UC [CD] from AD-SE were 0.03 (NS) [-0.19(p < 0.0011)].M2-PK sensitivities and specificities in distinguishing UC [CD] from AD-RV were 75.0%[71.4%] and 89.7% [89.7%] and for differentiation of UC [CD] from AD-SE were 56.3% [71.4%] and 95.2[57.1%]. CONCLUSIONS: The performance of M2-PK in distinguishing between children with moderate-to-severe IBD and patients with infectious gastroenteritis was inferior to FC. Neither test had sensitivity ands pecificity sufficient for everyday clinical application.

Comparison of fecal pyruvate kinase isoform M2 and calprotectin in acute diarrhea in hospitalized children.

Fecal concentrations of pyruvate kinase isoform M2 (M2-PK) and calprotectin (FC) serve as biomarkers of inflammation of gastrointestinal mucosa. The value of M2-PK in discriminating between patients with viral and bacterial acute diarrhea (AD) is currently unknown. We analyzed M2-PK and FC concentrations in fifty hospitalized children with AD (29 of which were caused by rotavirus and 21 by Salmonella enteritidis) as well as 32 healthy subjects. There was no difference in the areas under the receiver operating characteristic curves plotted for the two tests in differentiating rotaviral from bacterial AD. The sensitivity and specificity of M2-PK at optimal cut-off (20 U/g) were 75.9% and 71.4%, respectively. M2-PK and FC had similar values in distinguishing between children with AD caused by rotavirus and Salmonella enteritidis. The performance of both tests in hospitalized patients did not meet the needs of everyday clinical practice. Moreover, no advantage of fecal tests over the measurement of CRP was documented.

Comparison of fecal pyruvate kinase isoform M2 and calprotectin in assessment of pediatric inflammatory bowel disease severity and activity.

AIMS: Accurate assessment of inflammatory bowel disease (IBD) activity is the cornerstone of effective therapy. Fecal M2 isoform of pyruvate kinase (M2-PK) and fecal calprotectin (FC) are noninvasive markers of mucosal inflammation in IBD. The aim of this study was to compare performance of M2-PK and FC in assessment of pediatric ulcerative colitis (UC) and Crohn's disease (CD) severity and activity. MATERIALS AND METHODS: 121 patients with IBD, including 75 with UC and 46 with CD were recruited. Control group consisted of 35 healthy children (HS). Patients were assigned to groups depending on disease severity and activity. M2-PK and calprotectin concentration were determined in stool samples using ELISA. Areas under receiver operating characteristic curves (AUC) for FC and M2-PK with cut-off level at which M2-PK specificity was matching FC specificity were calculated and compared. RESULTS: Performance of M2-PK at identifying patients with IBD, UC and CD among HS was inferior to FC. The differences in AUC were respectively: -0.10 (95% confidence interval [CI] [-0.13-(-0.06)], p<0.0001), -0.14 (95% CI [-0.19-(-0.09)], p<0.0001) and -0.03 (95% CI [-0.05-(-0.001)], p<0.02). M2-PK was inferior to FC in discriminating patients with mild UC from those with HS (AUC difference -0.23, 95% CI [-0.31-(-0.15)], p<0.0001). CONCLUSIONS: FC reflects pediatric IBD severity and activity better than M2-PK. This difference is particularly pronounced when identifying patients with mild UC and UC in remission.

Fecal pyruvate kinase: a potential new marker for intestinal inflammation in children with inflammatory bowel disease.

OBJECTIVE: Inflammatory bowel disease (IBD) in children creates diagnostic and clinical challenges. Clinical data, endoscopic appearance and the histopathological assessment of biopsies are essential for diagnosis. However, new methods are required for non-invasive follow-up. Recently, we demonstrated that the dimeric isoform of pyruvate kinase (PK) detected in stool might serve as a potential non-invasive screening tool in inflamed pouch mucosa. The aim of this study was to investigate whether this test could be used to detect intestinal inflammation in pediatric IBD patients. MATERIAL AND METHODS: Fecal PK immunoreactivity was assessed in 75 patients with proven ulcerative colitis (UC) and 32 with Crohn's disease (CD). Pediatric Crohn Disease Activity Index (PCDAI) and Truelove-Witts scores were determined in CD and UC patients, respectively. Thirty-five healthy subjects (HS) served as a control group. RESULTS: Increased PK levels were documented in 94.1% and 100% active CD patients with a cut-off level of 5 U/g and a cut-off level of 4 U/g, respectively, and in 94.3% of active UC patients regardless of cut-off level. Enzyme immunoreactivity was significantly higher in all IBD patients than in HS. Abnormal PK results were documented in 71.7% of all IBD patients (65.3% and 84.4 for UC and CD patients, respectively). Enzyme levels in UC remission were significantly lower than in the active phase. Enzyme immunoreactivity significantly correlated to both scoring systems. CONCLUSIONS: The measurement of stool PK could be a potentially useful marker of IBD activity in children. However, its clinical value demands further studies for comparison with other tests.