Etiologic Study On Infantile Cholestatic Hepatitis Syndrome

ObjectiveCholestatic infantile hepatitis syndrome is the main type of infantile hepatitis syndrome (IHS). The etiology of is complex and part of patients with cholestatic IHS have a poor prognosis. Our study is to investigate the prognosis of children with cholestatic IHS, to find out the main pathologic characteristics of infantile cholestatic IHS and any clue indicating metabolistic diseases, to explore the human cytomegalovirus (HCMV) infection in cholestatic IHS and evaluate the specificity and sensitivity of the clinical examination for detecting HCMV, to investigate gene expression of bile salt export pump (BSEP) and multidrug resistance gene product3(MDR3) in liver tissues of patients with cholestatic IHS and demonstrate whether mutation of these genes relative with cholestatisis are involved in the development of infantile cholestatic hepatitis syndrome.Method1. The disease composition and prognosis in252hospitalized children with diagnosis of infantile hepatitis syndrome from2004.1to2006.6were investigated retrospectively.2. Liver biopsy guided by B ultrasound was performed in36cases of infantile cholestatic hepatitis syndrome. Liver tissues were observed under light microscope and electromicroscope. The probabilities of morphologic changes were analyzed and the results were compared with the clinical manifestations to make the clinical diagnosis and analyze the reason of mis-diagnosis.3. Serum HCMV-IgM, Tox-IgM, RuV-IgM, HSV-IgM, hepatitis virus marker (A, B, C and E) were detected by ELISA; urine HCMV-DNA was detected by real-time quantitative PCR assay; HCMV inclusion was detected in morning urine samples. Immediately early antigen (IEA) and early antigen (EA) of HCMV and HBcAg were detected in liver tissues by immunohistochemistry stain assay. Pathologic observations were compared between HCMV antigen positive samples and negative samples, and analyzed statistically by fisher exact test with SPSS11.5software. Specificity and sensitivity of the routine examinations for HCMV used in clinical practice were evaluated.4. BSEP was detected in the liver tissues from5cases with normal or decreased serum GGT level and MDR3was detected in the liver tissues from31cases with increased serum GGT level by immunohistochemistry stain assay.Result1. In252patients with IHS from2004.1to2006.6, retrospective investigation showed there were43(17%) with biliary abnormalities,64(25%) with hepatitis IHS,145(58%) with cholestatic IHS. There were188(75%) cases had cholestasis. One hundred and sixty five cases except biliary abnormalities were followed up successfully. In the165patients, there were117patients with cholestatic IHS in which55(47.0%) patients had poor prognosis and there were48patients with hepatitis IHS in which just3(6.4%) cases had poor prognosis.2. Morphologic changes under light microscope in liver tissues of36cases with cholestatic IHS included hepatocyte swelling, hepatocyte denaturation, hepatocyte necrosis, multinucleated giant cell formation, bile ductular and fiber tussiue proliferation, inflammatory cell infiltration in liver lobule and portal region. The characteristics of cholestasis were observed, including in intralobular cholestasis, acinus form, feather-like cytoplasmic filaments and bile stasis in bile canaliculi. The morphologic changes in7cases which biliary atresia was ruled out by image investigation showed obstruction of biliary tract. And combining with clinical manifestations, the diagnosis of biliary atresia was made in these7patients. Nuclear changes, resolution of cytoplasm, inflammatory cell infiltration, collagen fiber proliferation and increased number of lysosome were observed under electromicroscope. Two cases of glycogen storage disease,1case of Niemann-Pick disease and1case of lipid storage diseases with unknown cause were confirmed by the combination of histological changes and clinical manifestations.3. HCMV-IEA/EA was positive in liver tissues of22cases. Specificity of serum HCMV-IgM detection, urine HCMV-DNA real-time quantitative PCR assay detection or morning urine HCMV inclusion detection were77.8%,69.7%or51.5%respectively. There was no significant difference between HCMV positive and negative hepatitis in light microscope analyzed by SPSS software. There was only1case with HBcAg positive by immunohistochemistry stain assay. HCMV infection could be co-infected with other virus infection or patients with metabolic liver diseases and HCMV infection could exist together.4. BSEP were positive in liver tissues of5patients with low or normal GGT level and MDR3were positive in liver tissues of31patients with high GGT level by immunohistochemistry stain assay.ConclusionAlmost half of patients with cholestatic infantile hepatitis syndrome have a poor prognosis. There were common pathologic changes of liver tissues under light microscope and electroscope, and diagnosis of hereditary metabolic disorders could be made increasedly by application of these two technologies in clinical practice. It is difficult to diagnose biliary atresia in early childhood by image investigations sometimes, and the pathologic changes of liver tissues are helpful in diagnosis of biliary atresia in cholestatic IHS children whose image examinations is normal. HCMV hepatitis is the main cause of infantile hepatitis syndrome in Chongqing, but there are no specific pathologic changes. Active HCMV infection could be indicated by specific HCMV immediate early antigen and early antigen detection in liver tissues with HCMV monoclonal antibody by immunohistochemistry stain assay. Cholestatic genes BSEP and MDR3were both expressed on the membrane of hepatocytes, and our study suggested that PFICⅡ and PFICⅢ were scarce in the pathogenesis of infantile cholestatic hepatitis syndrome in our country.