Serum vascular endothelial growth factor per platelet count in patients with biliary atresia

Background: Biliary atresia (BA) is a progressive, sclerosing, inflammatory process resulting in complete obliteration of the extrahepatic bile ducts. The obstruction of bile flow engenders worsening cholestasis, hepatic fibrosis, and cirrhosis, which lead to portal hypertension and a decline in hepatic synthetic function. Hepatic stellate cells, which play roles in hepatic fibrogenesis, are an important source of various inflammatory mediators including vascular endothelial growth factor (VEGF) in the injured liver. Objectives: Investigate the level of serum VEGF and serum VEGF per platelet count in patients with BA and its relation to clinical characteristics. Methods: Peripheral blood samples were taken from 70 BA patients and 15 healthy control children. Serum VEGF was measured by enzyme-linked immunosorbent assay. We compared serum VEGF and serum VEGF per platelet count in BA patients with the respective results obtained in healthy control children. The relation of serum VEGF per platelet count with clinical variables of BA patients was investigated. Results: Serum VEGF levels and serum VEGF per platelet count in BA patients were not significantly different from those in normal controls (289.64±230.01 pg/mL vs. 312.36±189.05 pg/mL; p=0.72 and 1.72±1.21x106 vs. 1.57±0.97x106; p=0.66). Significant differences were observed among BA patients when VEGF per platelet count was categorized by the presence of esophageal varice (p=0.03). Only in BA patients was the serum level of VEGF correlated with the number of platelets (r=0.53, p<0.001). Conclusion: A high serum VEGF per platelet count is a useful marker for the development of portal hypertension in BA patients, especially for esophageal varice. Serum VEGF per platelet count may be useful for monitoring disease course in BA after hepatic portoenterostomy.

Problems and prevention of viral hepatitis in Thailand.

To this day, viral hepatitis remains a major public health problem in Thailand. Chronic infection with hepatitis B and C viruses are the leading causes of chronic liver diseases, including cirrhosis and hepatocellular carcinoma (HCC). Outbreaks of hepatitis A virus continue to occur in Thailand, even after several years of consistently declining prevalence rates. Also, the reduction in prevalence of hepatitis D virus infection has been observed among intravenous drug users over the past decade. Hepatitis E virus constitutes a rather unusual cause of sporadic acute hepatitis in Thailand. Highly effective vaccines are currently available for prevention of hepatitis A and B, however, as yet no effective vaccine for hepatitis C is imminent. Following rapid progress in the development of molecular techniques, several new hepatitis viruses have been identified. Among these, Hepatitis G, TT and SEN viruses have recently been described but their significance as to causation of human liver disease has yet to be established. This article reviews the current epidemiology, molecular biology, and strategies aimed at prevention and control of hepatitis virus infection in Thailand emphasizing new developments and recent data obtained from our research studies.

Immunogenicity and adverse effects of live attenuated varicella vaccine (Oka-strain) in children with chronic liver disease.

Varicella infection may cause significant morbidity and mortality especially in immunocompromised persons. Children with chronic liver disease who undergo liver transplantation and need long term immunosuppressive therapy are at risk to acquire the infection. Twenty-nine children (aged 1-12 years) with chronic liver disease were enrolled to receive one dose of live attenuated varicella vaccine (Oka-strain). During the 16-week follow-up period, no vaccine-related serious adverse events were reported. Seroconversion rates at 8 weeks post vaccination were 100%. Geometric mean titer (GMT) values and seropositive rates at 16 weeks tended to relate to the clinical severity of liver disease. This study demonstrates that varicella vaccine is safe and Immunogenic in children with chronic liver disease.

Humoral immune response following hepatitis B vaccine booster dose in children with and without prior immunization.

One hundred and twenty-three children who had received no, incomplete and complete primary hepatitis B vaccination but had negative or very low anti-HBs titer were immunized with a single dose of recombinant hepatitis B vaccine. Blood tests for anti-HBs were obtained at 30 +/- 5 days after the booster immunization. Twelve of 18 (66.7%) children without prior immunization (group 1) seroconverted following the single dose Seroconversion rates in children who had undetectable anti-HBs with incomplete and complete primary immunization (group 2 and 3) were 83.34% and 94.5%, respectively. All children with complete 3- dose vaccination but who had low anti-HBs titer (group 4) also seroconverted. This study confirmed that immunological memory, allowing a protective anamnestic response, lasted at least 8 years in children who had received primary HB immunization with undetectable anti-HBs. Therefore, we conclude that the booster dose after complete vaccination is not necessary in healthy children.

Detection of HbsAg and HBV DNA in serum and saliva of HBV carriers.

Serum and saliva samples from 23 patients known to be HBsAg-positive HBV carriers and 17 healthy control subjects were analyzed for hepatitis B virus (HBV) by enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). All serum samples of the HBV carriers were positive for HBsAg, with 21 also positive for HBV DNA. In comparison, 22 saliva samples of HBV carriers were positive for HBsAg whereas only 11 of the 23 tested were positive for HBV DNA. Based on these results we have arrived at the conclusion that the saliva of HBV carriers might be potentially infectious and also that saliva testing could serve as an alternative technique for identifying HBV carriers.

Hepatocellular carcinoma: significance of HBV vertical transmission.

In two cases of childhood hepatocellular carcinoma in Thailand, we established vertical transmission of hepatitis B virus infection as the underlying cause. With the first patient, the family history of HBV carriage became evident and a pedigree could be devised which demonstrated the high prevalence among the family members and hence evidence of vertical transmission. In the case of the second patient, we performed PCR and subsequent direct sequencing of HBV DNA isolated from his HBsAg-positive mother's, as well as from his serum, comparing the nucleotide sequences with those of a pregnant woman diagnosed as an asymptomatic HBV carrier, of another asymptomatic HBV carrier and of a reference strain, respectively, all belonging to the same genotype and subtype as the samples tested. Our results clearly indicate the necessity for nation-wide hepatitis B vaccination starting at birth, at least in hyperendemic areas like the Far East, in order to forestall HBV carriage and ensuing cirrhosis and/or HCC by preventing vertical transmission.

Comparison study of combined DTPw-HB vaccines and separate administration of DTPw and HB vaccines in Thai children.

The safety, immunogenicity and tolerability of two different DTPw-HBV combination vaccines, containing 5 and 10 microg of HBsAg; were investigated in comparison with separate administration of DTPw and HBV (10 microg of HBsAg). A three dose primary vaccination course at 2, 4 and 6 months of age was followed by a booster dose at 18 months. All vaccines were safe and well tolerated. The DTPw-HBV combination vaccine containing 10 microg of HBsAg elicited significantly higher anti-HBs titres than the other two vaccines after the primary and booster vaccination course. All vaccines elicited a high response against the other components. Based on these results, DTPw-HBV (10 microg HBsAg) was the most effective vaccine at this schedule.

Non-cirrhotic portal fibrosis associated with pulmonary arteriovenous communication and pulmonary arterial hypertension.

A case of non-cirrhotic portal fibrosis associated with pulmonary arteriovenous communication and pulmonary arterial hypertension is reported. The patient was a 7-year old boy who presented with hematemesis, cyanosis, hypoxemia and orthodeoxia. His liver pathology was compatible with non-cirrhotic portal fibrosis. His pulmonary angiography showed arteriovenous shunting and pulmonary arterial hypertension (mean pulmonary artery pressure 34 mmHg). His sister also had non-cirrhotic portal fibrosis with neither hypoxemia nor orthodeoxia. This report raises the possibility of non-cirrhotic portal fibrosis having a genetic etiology.

Alpha 1-antitrypsin phenotype of children with liver diseases in Thailand.

Alpha1-antitrypsin deficiency (PiZZ) constitutes not only the most common hereditary cause of liver diseases, but also of the most prevalent metabolic diseases in need of liver transplantation. It is a codominantly inherited disorder which predisposes to chronic liver disease, usually beginning in early infancy. The purpose of the present study has been to investigate alpha 1-antitrypsin phenotype in pediatric patients with various liver diseases. Phenotypic identification of alpha 1-antitrypsin variants has been carried out in 69 children with various liver diseases and 100 healthy controls using isoelectric focusing on polyacrylamide gel slabs. PIMM represents the most common phenotype detected in both groups (92% in the group with liver diseases and 88% in normal controls). We could detect PiZZ in only one healthy child but in none of those with liver diseases. Consequently alpha 1-antitrypsin deficiency does not appear to be a common cause for liver disease among children in Thailand. Further studies are necessary to elucidate the frequency of various alpha 1-antitrypsin variants and the clinical relevance with respect to liver diseases in Thailand.

High prevalence of antibody against hepatitis A virus in an institution for the mentally handicapped.

Hepatitis A virus infection constitutes a world-wide public health problem, predominantly in developing countries. Mentally handicapped children, due to their incapacity for looking after themselves, comprise one of the high risk groups for hepatitis A virus infection. The aim of the present study was to determine the prevalence of hepatitis A virus antibody (anti-HAV) among the children and adults in the Institute for the Mentally Handicapped located in Nonthaburi, Thailand. The prevalence of anti-HAV IgG antibody was 92%. Immunity acquired against HAV was shown to increase in direct proportion to the age. To prevent future outbreaks of hepatitis A, water supply, sanitary conditions and personal hygiene should be improved at this and similar institutions. Furthermore, persons new to the institution (patients and staff) should be screened for anti-HAV and vaccinated with hepatitis A vaccine if nonimmune.

Is there evidence for intrauterine HBV infection in newborns of hepatitis B carrier mothers?

It has been proposed that some neonates infected with hepatitis B virus (HBV), acquire their infections in utero as demonstrated by HBV seromarkers in venous blood samples at birth. In this study, paired blood samples from 13 HBsAg-positive, 19 HBsAg- and HBeAg-positive, 2 HBsAg-negative mothers and 34 of their neonates, were drawn 24-72 hours after birth and tested for HBV-DNA in their peripheral blood mononuclear cells (PBMC). The presence of HBV-DNA in PBMC was detected in 69.2% (9/13) of HBsAg-positive mothers, 94.7% (18/19) of HBsAg- and HBeAg-positive mothers, and in none of their neonates. The conclusion from these results is that the evidence for hepatitis B infections occurring in neonates of hepatitis B carrier mothers in utero is uncommon.

The declining pattern of seroepidemiology of hepatitis A virus infection among adolescents in Bangkok, Thailand.

Hepatitis A virus (HAV) is a health problem in countries where seroepidemiology shows changes from hyperendemicity to intermediate endemicity. Throughout the last decade, we studied, in Bangkok, the seroprevalence of hepatitis A virus antibody (anti-HAV) among adolescents of different age groups. In 1996, 245 serum specimens from children aged between 10 and 19 were tested for anti-HAV by ELISA method. The results were compared to those obtained in 1987 and 1993 from students of the same age and attending the same school. Anti-HAV was detected in 31.4%, 14.6% and 12.7% of school children in the years 1987, 1993 and 1996, respectively. Each year, it was found that an increasing prevalence of anti-HAV was related to an increasing age. From 1987 to 1996, the age specific prevalence of anti-HAV was markedly decreased in younger children. The surveillance of the epidemiological trend of HAV infection is important for implementing preventive measures and for controlling the disease.

Extrahepatic biliary atresia in twins: zygosity determination by short tandem repeat loci.

Extrahepatic biliary atresia (EHBA) is an infantile obstructive cholangiopathy of unknown etiology. This condition is generally thought to be an acquired disease without familial tendency. We reported eight pairs of discordant twins in a series of 143 patients with operatively established EHBA, One pair was dizygotic twin from sex discrimination. Six were identical ABO blood groups and 2 were also the same minor blood groups (Dce, MM and Le a-b-). The last 2 sets were monzygotic twins by common DNA polymorphisms short tandem repeat loci. Our findings support the hypothesis that, EHBA is an acquired rather than a hereditary disease.