ABSTRACT
<p><b>OBJECTIVE</b>To investigate the difference of serum high molecular weight alkaline phosphatase (HMAP) levels between biliary atresia (BA) and neonatal hepatitis (NH), and to develop a new differential method and early diagnostic indicators for cholestatic jaundice in neonates.</p><p><b>METHODS</b>Totally 31 patients with cholestatic jaundice seen between Aug. 2000 and Feb. 2002, including 15 cases with BA, 16 cases with NH, 30 healthy infants and 30 infants with non-cholestatic jaundice were enrolled in this study. Serum samples were obtained from each subject by using venipuncture. The samples were stored at -80 degrees C and analyzed within 6 months. A murine hybridoma producing monoclonal antibody to human high molecular weight alkaline phosphatase (MoAb HMAP-1) was prepared by using partially purified HMAP from human serum as the immunogen. The antibody did not cross-react with other alkaline phosphatase (ALP) isozymes. A monoclonal antibody immunocatalytic assay for HMAP in serum was developed by using MoAb HMAP-1 bound to nitrocellulose membrane discs. The serum total ALP (TALP) and gamma-GT were determined in the meantime, the hepatobiliary ultrasonography and scintigraphy were performed too. The data were analyzed with t test, chi-square test and percentage. Comparisons were made between BA and NH with their sensitivity and specificity in different methods.</p><p><b>RESULTS</b>Serum HMAP was detected in 14 of 15 patients of BA, in 2 of 16 NH patients, while in none of the healthy control group. The positive ratios of serum HMAP in BA and NH were 93.3% and 12.5%, respectively (P < 0.005). The sensitivity and specificity of serum HMAP in BA and NH were 93.3% and 87.5%, respectively. The sensitivity and specificity of TALP, gamma-GT and hepatobiliary scintigraphy were 80.0%, 73.3%, 86.7% and 62.5%, 68.8%, 62.5%, respectively, which were clearly lower than those of serum HMAP.</p><p><b>CONCLUSIONS</b>The determination of serum HMAP was more sensitive and specific than the other methods tested. Therefore the method can be used as a useful indicator for cholestatic jaundice in neonates, although it needs further study.</p>