Questioning Diagnostic Value of Serum Matrix Metalloproteinase 7 for Biliary Atresia

Matrix metalloproteinase 7 (MMP7) has been suggested as a promising biomarker in diagnosing biliary atresia (BA). This study aimed to assess the diagnostic accuracy of serum MMP7 in BA in the Middle Eastern population.

In this cross-sectional study, neonates and infants with direct hyperbilirubinemia admitted to Namazi referral hospital, Shiraz, Iran, were studied. Baseline demographic and clinical characteristics and blood samples were obtained on admission. MMP7 serum concentration was measured using an enzyme-linked immunosorbent assay (ZellBio GmbH, Ulm, Germany).

44 infants with a mean age of 65.59 days were studied. Of these patients, 13 cases were diagnosed with BA, and 31 cases' cholestasis related to other etiologies. Serum MMP7 concertation was 2.13 ng/mL in the BA group and 1.85 ng/mL in the non-BA group. MMP7 was significantly higher in those presented with either dark urine or acholic stool. The predictive performance capability of the MMP7 was not significant in the discrimination of BA from the non-BA group based on receiver operating characteristic curve analysis (area under curve: 0.6, 95% confidence interval: 0.45-0.75). In the optimal cut of point 1.9, the sensitivity and specificity were 84.6% and 45.1%, respectively. Further combination of MMP7 with Gamma-glutamyl transferase (GGT), alkaline phosphatase, direct and total bilirubin, and dark urine or acholic stool was not remarkably boosted the diagnostic accuracy of the test. Interestingly, GGT at a cut-off point of 230 U/L was 84.6% sensitive and 90.3% specific for BA.

Our results are not consistent with previous studies on this subject. Considering more conventional and available tests like GGT besides conducting future studies with greater samples and different geographical areas is recommended.