Role of a homozygous A(TA)₇TAA promoter polymorphism and an exon 1 heterozygous frameshift mutation UGT1A1 in Crigler-Najjar syndrome type II in a Thai neonate

Crigler-Najjar syndrome is a rare autosomal recessive disease caused by mutations in the UGT1A1 gene. These mutations result in the deficiency of UGT1A1, a hepatic enzyme essential for bilirubin conjugation. This report describes the case of a 4-month-old boy with the cardinal symptoms of Crigler-Najjar syndrome type II. Molecular genetic analysis showed a homozygous UGT1A1 promoter mutation [A(TA)7TAA] and a heterozygous insertion of 1 adenosine nucleotide between positions 353 and 354 in exon 1 of UGT1A1 that caused a frameshift with a premature stop codon.

Elevated serum IL-18 and interferon-gamma in medium-term survivors of biliary atresia

INTRODUCTION

Biliary atresia (BA) is a fatal disease in children. Its main pathological feature is progressive immune-mediated cholangiopathy. Interleukin (IL)-12, IL-18, and interferon-gamma (IFN-gamma) play important roles in various immunological diseases.

THE OBJECTIVE

was to investigate whether these serum markers were associated with clinical outcome in BA.

METHODS

Serum levels of IL-12, IL-18, and IFN-gamma were determined using enzyme-linked immunosorbent assay from 46 BA patients (median age of 9 years) and 19 normal controls. The BA patients were then categorized into three groups according to their outcome: jaundice-free (29 cases), mild to moderate jaundice (10 cases), and marked jaundice (7 cases). The comparisons of serum IL-12, IL-18, and IFN-gamma levels among groups of the patients were performed using one-way analysis of variance with post-hoc tests. Data are expressed as mean + standard deviation.

RESULTS

Serum IL-18 and IFN-gamma in BA patients were higher than the normal controls (IL-18: 113.3 + 82.6 vs. 80.5 + 9.9 pg/mL, p = 0.011 and IFN-gamma: 41.7 + 5.1 vs. 38.0 + 1.9 pg/mL, p < 0.001). There was no difference in serum IL-12 between BA and controls. Further analysis demonstrated that, in BA patients, only serum IL-18 levels significantly increased with the degree of jaundice (test for trend, p = 0.004).

CONCLUSIONS

Serum IL-18 and IFN-gamma levels were increased in medium-term survivors of BA. The elevated serum IL-18 in BA patients was associated with worse clinical outcome. These results suggest that IL-18 and IFN-gamma play roles in the pathophysiology of BA. Additionally, IL-18 is likely to be involved in the disease progression.

Elevation of serum galectin-3 and liver stiffness measured by transient elastography in biliary atresia

BACKGROUND AND AIM

Biliary atresia (BA) is an intractable neonatal liver disease characterized by progressive fibrosclerotic obliteration of the extrahepatic biliary tree. The aim of this study was to evaluate serum galectin-3 in postoperative BA patients and the association between galectin-3, clinical outcome and liver stiffness score.

METHODS

58 BA patients post Kasai operation and 20 controls were enrolled. None of the patients had undergone liver transplantation. BA patients were classified into 2 groups according to their serum total bilirubin (TB) levels (TB<2 mg/dL, no jaundice vs. TB≥2 mg/dL, persistent jaundice) and alanine aminotransferase (ALT) levels (ALT<45 IU/L, normal ALT vs. ALT≥45 IU/L, elevated ALT). Serum galectin-3 levels were determined by enzyme-linked immunosorbent assay. Liver stiffness scores were measured by transient elastography (FibroScan).

RESULTS

BA patients had higher serum galectin-3 levels (5.1±0.3 vs. 3.8±0.4 ng/mL, p=0.01) and greater liver stiffness values than healthy controls (29.7±3.0 vs. 5.1±0.5 kPa, p<0.001). Serum galectin-3 levels were markedly elevated in BA patients with jaundice compared to those without jaundice (6.4±0.5 vs. 4.4±0.3 ng/mL, p=0.001). Furthermore, BA patients with elevated ALT displayed significantly higher levels of serum galectin-3 than those with normal ALT (5.9±0.4 vs. 3.8±0.3 ng/mL, p=0.001). Additionally, BA patients with portal hypertension had considerably higher serum galectin-3 levels than those without portal hypertension (6.1±0.4 vs. 3.7±0.3 ng/mL, p<0.001).

CONCLUSIONS

Increased serum galectin-3 is associated with a poor outcome in postoperative BA patients. Serum galectin-3 could be used as a biochemical parameter reflecting the deterioration of liver function and the severity of liver fibrosis in postoperative BA.

Evidence of protection against clinical and chronic hepatitis B infection 20 years after infant vaccination in a high endemicity region

Vaccination against hepatitis B virus (HBV) immediately after birth prevents neonatal infection by vertical transmission from HBV carrier mothers. There is an ongoing debate whether infant vaccination is sufficient to protect against infection when exposed to HBV later in life. We studied 222 Thai infants born to HBsAg -/+ and HBeAg -/+ mothers who were vaccinated with recombinant hepatitis B vaccine at 0-1-2-12 months of age. A subset of 100 subjects received a booster dose at age 5 years. Blood samples collected yearly for 20 years were examined for anti-HBs antibodies and serological markers of hepatitis B infection (anti-HBc, HBsAg, and in selected cases HBeAg, anti-HBe, HBV DNA). During the 20-year follow-up, no subject acquired new chronic HBV infection or clinical hepatitis B disease. During the first decade, possible subclinical breakthrough HBV infection (anti-HBc seroconversion) was only observed in subjects born to HBsAg +/HBeAg + mothers (6/49 [12.2%]). During the second decade, breakthrough HBV infections were detected in all groups (18/140 [12.8%]). Increases in anti-HBs concentrations that were unrelated to additional HBV vaccination or infection were detected in approximately 10% of subjects in each decade. Primary infant vaccination with a recombinant hepatitis B vaccine confers long-term protection against clinical disease and new chronic hepatitis B infection despite confirmed hepatitis B exposure.

Correlation of circulating endoglin with clinical outcome in biliary atresia

BACKGROUND AND AIM

Biliary atresia (BA) is a chronic progressive inflammatory disorder of the extrahepatic and intrahepatic biliary system in children. The aim of the present study was to investigate circulating endoglin levels in BA patients compared with healthy controls and to determine the relationship between plasma endoglin levels and outcome parameters of BA patients after Kasai operation.

METHODS

Fifty-five postoperative BA patients and 14 healthy controls were recruited. The patients were divided into two groups based on their serum total bilirubin levels (TB<34.2, no jaundice vs. TB>or=34.2 micromol/L, persistent jaundice) and serum alanine aminotransferase (ALT<45, normal ALT vs. ALT>or=45 IU/L, high ALT). Circulating endoglin levels were analyzed by enzyme-linked immunosorbent assay.

RESULTS

Average levels of plasma endoglin were significantly higher in BA patients compared to healthy controls (7.8+/-0.4 vs. 6.5+/-0.4 ng/mL; P=0.02). BA patients with persistent jaundice had higher plasma endoglin levels than those without jaundice (9.2+/-0.8 vs. 6.9+/-0.3 ng/mL; P=0.006). Furthermore, the concentrations of plasma endoglin in BA patients with high ALT were significantly higher compared to those with normal ALT (8.5+/-0.5 vs. 6.3+/-0.5 ng/mL, P=0.003). In addition, BA patients with portal hypertension had more elevated plasma endoglin levels than those without portal hypertension (8.8+/-0.6 vs. 6.1+/-0.3 ng/mL, P=0.001). Plasma endoglin was positively correlated with serum ALT (r=0.36, P=0.007) and serum GGT (r=0.44, P=0.001).

CONCLUSION

High circulating endoglin correlated with a poor outcome for BA. Plasma endoglin can be utilized as a potential biomarker reflecting the severity of ongoing liver injury and biliary obstruction in BA patients after Kasai procedure.

Cyclooxygenase-2 overexpression is associated with clinical outcome in biliary atresia

OBJECTIVE

The purpose of this study was to investigate the association between cyclooxygenase-2 (COX-2) expression and clinical outcome in biliary atresia (BA) patients.

METHODS

Six months after surgery, twenty-eight BA patients were divided into three groups according to their liver function tests: group A with satisfactory liver function (n=11), group B with moderate liver dysfunction (n=8), and group C with severe liver dysfunction (n=9). COX-2 expression was determined by immunohistochemistry. Choledochal cysts (n=5) and normal liver samples (n=4) served as controls.

RESULTS

Our data have shown that the intrahepatic biliary epithelium in BA specimens expressed COX-2. The mean immunoreactive score of COX-2 in BA patients was significantly higher than that in choledochal cyst and normal liver (4.0+/-0.6, 0.9+/-0.3, and 0.7+/-0.3, respectively, p<0.002). Strong expression of COX-2 was observed in BA patients with severe liver dysfunction. Subgroup analysis showed that the mean COX-2 immunoreactive scores of patients in group A, B, and C were 2.1+/-0.6, 3.6+/-1.1, and 5.9+/-0.9, respectively. The COX-2 immunoreactive score in BA patients with severe liver dysfunction was higher than in patients with satisfactory liver function (p<0.005).

CONCLUSION

Increased COX-2 expression of biliary epithelial cells at the time of Kasai operation was associated with an adverse therapeutic outcome in BA, suggesting that COX-2 could play a plausible role in the liver pathology of BA.

Elevated serum bone morphogenetic protein 7 levels and clinical outcome in children with biliary atresia

BACKGROUND AND AIM

Biliary atresia (BA) is one of the most serious liver disorders in children. The purposes of the present study were to investigate serum levels of bone morphogenetic protein 7 (BMP7) in BA children compared with healthy controls and to evaluate the association between serum BMP7 and the clinical outcome of BA patients post Kasai operation.

METHODS

Sixty-two BA patients post Kasai operation and 14 healthy controls were enrolled. The patients were divided into two groups according to their serum total bilirubin levels (TB<2, no jaundice vs. TB> or =2 mg/dL, persistent jaundice) and alanine aminotransferase levels (ALT<45, normal ALT vs. ALT> or =45 IU/L, elevated ALT). Serum BMP7 levels were determined by commercial enzyme-linked immunoabsorbent assay.

RESULTS

The mean serum BMP7 was higher in BA patients compared with that of healthy controls (35.4+/-3.6 vs. 20.6+/-2.7 pg/mL, p=0.002). The BA patients with persistent jaundice had more elevated serum BMP7 levels than those without jaundice (59.5+/-6.5 vs. 20.3+/-1.6 pg/mL, p=0.001). There was also a correlation between serum total bilirubin and serum BMP7 levels (r=0.57, p<0.001). Moreover, the levels of serum BMP7 in BA patients with elevated ALT were significantly higher than those with normal ALT (41.6+/-4.7 vs. 22.4+/-4.2 pg/mL, p=0.003). Additionally, BA patients with portal hypertension had higher increased serum BMP7 levels compared to those without portal hypertension (45.3+/-4.9 vs. 18.7+/-2.8 pg/mL, p<0.001).

CONCLUSION

The significant increment of serum BMP7 was associated with a deterioration of hepatic function and the progression of liver fibrosis. Serum BMP7 could be used as a prognostic marker to reflect disease severity and monitor disease progression in BA patients post Kasai operation.

Molecular characterisation of the hepatitis A virus circulating in the 2001-2005 outbreaks in Thailand

In a recent study of hepatitis A virus (HAV) in Thailand, viral isolates recovered during several outbreaks of infection that occurred between 2001 and 2005 were genotyped and subjected to phylogenetic analysis. Anti-HAV IgM was detected, by ELISA, in many of the 283 serum samples that were collected from the provinces of Suphanburi, Songkhla, Chiangrai and Lampang: 40 (48.2% of those investigated), 38 (47.5%), 25 (41.0%) and 32 (54.2%), respectively. The HAV RNA in the positive samples was reverse transcribed and amplified, using a nested PCR focussed on the VP1-2A region, before the nucleotides of the VP1-2A region of each HAV-RNA-positive sample were sequenced. All the isolates investigated clustered in subgenotype IA and, hence, are closely related to the strains previously investigated in Thailand. When the genome of one sample from an outbreak in Lampang (LP014) was fully sequenced, the results of genome comparison and phylogenetic analysis again indicated subgenotype 1A, which appears to be the predominant form of HAV circulating throughout Thailand.

Declining trend in the seroprevalence of infection with hepatitis A virus in Thailand

Since the mid 1970s, infection with hepatitis A virus (HAV) in Thailand has shifted from hyper-endemic to mesoendemic. In 2004, to explore this trend in prevalence further, 3997 subjects from four geographically distinct provinces of Thailand were tested, in a commercial ELISA, for antibodies to HAV. The results indicate that the seroprevalence of HAV continues to fall, almost certainly because the profound socio-economic development that has occurred over the last few decades in Thailand has brought with it significant improvements in sanitation and personal hygiene. As exposure to HAV declines, however, the risks of symptomatic and potentially severe infection in adulthood (rather than asymptomatic infection during childhood) and of epidemics of such infection, which would lead to profound economic loss, increases. Improvements in hygiene and sanitation to reduce exposure to the virus and measures to reduce the incidence of symptomatic disease in those infected, such as vaccination (which may only be cost-effective when targeted at high-risk groups), need to be carefully considered.

The incidence of rotavirus a isolates of G genotype in Thailand in 2002-2004

Rotaviruses are the leading cause of severe gastroenteritis among infants and young children worldwide. Between November 2002 and March 2004, 36 stool specimens of 108 children with acute diarrhea in Bangkok, Thailand were found positive for Rotavirus A (RV-A) by RT-PCR. The 36 isolates were subjected to genotyping by RFLP analysis and direct sequencing of a part of the gene for major outer capsid glycoprotein VP7. The sequences obtained were subjected to phylogenetic analysis. Among the isolates the genotypes G1 (5.6%), G2 (69.4 %) and G9 (25.0 %) were found. Comparison of these results with those of previous studies covering the period of 1982-1999 revealed a changing pattern of RV-A G genotypes and thus contributed to the understanding of RV-A epidemiology in Thailand. Any vaccine to be developed against this virus should target the G9 genotype as one of common global genotypes.

Relationship between vasoactive intestinal peptide and intrapulmonary vascular dilatation in children with various liver diseases

AIM

To evaluate the potential of vasoactive intestinal peptide (VIP) as a pathogenic factor of intrapulmonary vascular dilatation (IVD) in hepatopulmonary syndrome (HPS).

BACKGROUND

HPS comprises a triad comprising liver dysfunction, IVD and hypoxaemia. Although the pathogenesis of the process has not been elucidated, many vasodilating substances, such as VIP, have been implicated in the development of pulmonary vascular abnormalities. IVD can be detected by contrast-enhanced echocardiography (CEE) before the development of abnormal gas exchange.

METHODS

Forty-two children (20M, 22F; mean age 4.39 +/- 4.17 y) with various liver diseases who attended the paediatric liver clinic of King Chulalongkorn Memorial Hospital between March 2000 and February 2001 were recruited to the study. Each patient was tested for transcutaneous O2 saturation, CEE (applying the agitated normal saline technique), liver function test and serum VIP level.

RESULTS

Fourteen of the 42 patients (33%) were CEE positive. Only one of the 14 patients had associated hypoxia and clinical cyanosis. The serum VIP levels of children with liver disease were significantly higher than those of the controls (60.21 +/- 35.04 pg/ml vs 43.71 +/- 34.61 pg/ml, p = 0.03). CEE-positive children tended to have higher serum VIP levels than CEE-negative children (72.65 +/- 40.31 vs 53.99 +/- 31 pg/ml, p = 0.3). The serum VIP levels of biliary atresia (BA) patients with favourable outcomes (serum bilirubin < or = 34 micromol/L) were not significantly different from those with unfavourable outcomes (serum bilirubin > 34 micromol/L) (42.95 +/- 14.53 pg/ml vs 66.07 +/- 32.17 pg/ml, p = 0.5).

CONCLUSIONS

CEE is a non-invasive test for early detection of IVD in children with liver disease. VIP is not solely responsible for the pathogenesis of IVD in HPS. Further studies are required to determine which substances cause the development of IVD.

Plasma endothelin-1 levels in patients with biliary atresia: possible role in development of portal hypertension

BACKGROUND

Biliary atresia (BA) is a severe neonatal liver disease characterized by progressive extrahepatic biliary tract and intrahepatic inflammatory process. Hepatic fibrosis and portal hypertension (PH) still occur despite the disappearance of jaundice following successful hepatic portoenterostomy. Endothelin-1 (ET-1) is a potent vasoconstrictor and has been reported to stimulate hepatic collagen synthesis. The aim of this study was to demonstrate the potential role of ET-1 in the pathogenesis of the progressive inflammation, fibrosis and PH in BA.

METHODS

Thirty pediatric patients with biliary atresia post-hepatic portoenterostomy and 12 healthy children were examined. The ET-1 level was determined by commercially available enzyme-linked immunosorbent assay kits.

RESULTS

Endothelin-1 levels were elevated in the patients compared with those of the controls (5.45+/-3.34 vs. 2.74+/-2.17 pg/ml, P = 0.01). Moreover, patients with PH also had greater levels of ET-1 than those without PH (6.73+/-3.27 vs. 3.26+/-2.2 pg/ml, P = 0.004). Patients with abnormal transaminase enzymes had significantly higher ET-1 levels than those with normal enzymes (6.43+/-3.33 vs. 3.17+/-2.1 pg/ml, P = 0.01). In the jaundice-free group, endothelin-1 levels were elevated in the patients with PH compared with those without PH (5.93+/-2.15 vs. 2.88+/-2.1 pg/ml, P = 0.02).

CONCLUSIONS

Our findings showed elevation of plasma ET-1 levels in patients with BA, especially in those with PH. ET-1 levels were also higher in patients with elevated transminase enzymes as well as in the jaundice-free group with PH. ET-1 might play a role in the pathogenesis of the progressive inflammation, fibrosis and PH in BA.

Molecular characterization of hepatitis-A-virus infections, in the context of two outbreaks in southern Thailand

As hepatitis A virus (HAV) is usually transmitted through the faecal-oral route, hepatitis A is a communicable disease. In countries of intermediate to low endemicity, sudden outbreaks of human infection with the virus may occur. Between September 2001 and April 2002, there were two outbreaks of HAV infection in the Ruso and Yeengor districts of Narathiwas province, in southern Thailand. Isolates of HAV were recovered during these outbreaks, from 14 in-patients with acute hepatitis in Ruso (12 positive for anti-HAV IgM and all positive for HAV RNA), 16 children with asymptomatic infection in Yeengor (14 positive for anti-HAV IgM and nine for HAV RNA), and four isolated cases in Bangkok (all positive for anti-HAV IgM). Molecular characterization of the VP1-P2A region of each isolate was followed by phylogenetic analysis. All of the isolates from Narathiwas province were found to be of genotype 1a, to have the same VP1 nucleotide sequence, and to show a high level of sequence homology (>/= 99.5%) with the isolates from Bangkok and with previous Thai isolates. These results should facilitate further research into HAV transmission and genotype identification in community outbreaks.

Hepatitis D virus infection in Thailand: HDV genotyping by RT-PCR, RFLP and direct sequencing

BACKGROUND

Hepatitis D virus (HDV) is a degenerate RNA virus or virusoid that requires the surface coat of hepatitis B virus (HBV), i.e. hepatitis B surface antigen (HBsAg), in order to become infectious. Three distinct genotypes of the virus have been classified. In this study, HDV genotypes were determined by restriction fragment length polymorphism (RFLP) and direct sequencing. In Thailand, simultaneous HDV/HBV infections are particularly prevalent among intravenous drug users (IVDU).

PATIENTS AND METHODS

A total of 743 IVDU sera were screened for HBV infection. HBsAg-positive samples were subjected to serological analysis for anti-HDV. RFLP analysis using the endonucleases Xho I and Sma I was performed on the PCR amplified HDV genome to establish the prevailing HDV genotypes.

RESULTS

55 sera (7%) had detectable HBsAg; all 55 were subsequently subjected to serological analysis for anti-HDV, 12 (21.8%) of which were positive. Eight (66%) specimens had detectable HDV-RNA by RT-PCR. All polymorphisms were shown to be genotype I, a finding confirmed by direct sequencing. 36 HBsAg-positive sera obtained from the blood bank to serve as controls were negative for anti-HDV.

CONCLUSION

Our data show that HDV infection is still limited among IVDU and that the pattern of polymorphism closely resembles that of the western HDV genotype I.

Bone density and 25-hydroxyvitamin D level in extrahepatic biliary atresia

Biliary atresia (BA) represents a common cholestatic affliction of the gastrointestinal tract affecting infants and children. The objective of the present study was to evaluate 42 patients (20 with and 22 without jaundice) diagnosed with extrahepatic BA for bone mineral content and serum 25-hydroxyvitamin D (HVD) levels. Physical examination and anthropometric nutritional assessment were performed. The investigation included liver function tests and serum calcium (Ca), phosphate (P), magnesium (Mg), and 25-HVD levels. Dual-energy X-ray absorptiometry was used to measure the bone mineral density (BMD) of the lumbar spine (L(1)-L(4)). Our results showed that 16 jaundiced patients (80%) and only 3 nonjaundiced patients (13.6%) showed osteoporosis (P< 0.05). All patients had normal serum Ca and P levels. Only 1 nonjaundiced patient had a low serum Mg level. Serum 25-HVD levels (mean +/- SD) were 20.71 +/- 8.24, 16.12 +/- 4.3, and 9.18 +/- 5.84 ng/ml, respectively, in subjects with normal bone density (n=7), osteopenia (n=3), and osteoporosis (n=11). Bone disease represents a well-known complication among long-term survivors of BA. To date, the pathogenesis has remained unexplained. Since, as demonstrated in the present study, jaundiced patients develop osteoporosis more frequently than nonjaundiced patients, hyperbilirubinemia may have an influence. Bone-mineral deficiency can be detected earlier by means of BMD measurement (non-invasive method) than by measuring serum Ca, P, and Mg levels in these patients.

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.

Variants within the "a" determinant of HBs gene in children and adolescents with and without hepatitis B vaccination as part of Thailand's Expanded Program on Immunization (EPI)

A total of 2229 children selected from five distinct areas of Thailand were screened for HBs antigen (HBsAg) by ELISA. Out of 51, forty-nine HBsAg-positive children were further examined for HBV-DNA by the polymerase chain reaction, utilizing the region of the hepatitis B Virus (HBV) genome encoding the major antigenic epitopes of hepatitis B surface antigen. Direct automated sequencing of the "a" determinant region revealed 11 of 49 children to display variable mutations. The vaccinated and nonvaccinated children had amino acid variants clustered between residues 120 and 160. Mutations between residues 120 and 160 were found at higher frequency in the vaccinated group (4/13; 30.8%) than in the nonvaccinated group (7/36; 19.4%), but this was not statistically significant. Infections with new HBV variants are contracted either vertically or horizontally within the group having received the vaccine, a finding confirmed by the presence of amino acid substitutions critical for immune escape. Hence, neither vaccine nor IgG has any apparent effect on those variants and the children turn into HBV carriers. However, the current vaccination program still efficiently protects perinatal transmission of HBV and unless long term studies lead us to conclude otherwise, inclusion of the variant strain(s) into a new vaccine formulation is not deemed necessary.

Acute posttransfusion hepatitis C: identification of a common hepatitis C virus strain in donor and recipient using polymorphism analysis

An 11-year-old Thai boy who had received multiple blood transfusions from 12 different donors for treatment of Dengue shock syndrome presented with symptoms of acute hepatitis 5 weeks thereafter. He was found positive for antibodies to hepatitis C virus (HCV) and HCV-RNA was detected by reverse transcription PCR (RT-PCR). When his alanine aminotransferase (ALT) level peaked at 1,879 U/l in the 8th week, interferon therapy (3 million units, thrice weekly for 6 months ) was initiated. After initially decreasing to tenfold the normal level, the ALT dropped to fivefold the normal level at 6 months. HCV RNA is still detectable in his serum 6 months later. Using RT-PCR and subsequent restriction fragment length polymorphism (RFLP) analysis we identified one of the donors as harboring HCV genotype 3a, identical to that found in the patient. Moreover, polymorphism analysis on the hypervariable region employing five distinct restriction endonucleases suggested this donor as the source of infection. We hence recommend thorough screening of all blood donors as the only means of prevention presently feasible.

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.

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.

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.

Molecular analysis of the a determinant of HBsAg in children of HBeAg-positive mothers upon failure of postexposure prophylaxis

OBJECTIVE

To investigate the a determinant of hepatitis B virus (HBV) S gene for the presence of mutations responsible for vaccine failure.

METHODS

The a determinant of HBV S gene was amplified in sera obtained from 11 HBV-positive infants and children born to asymptomatic HBeAg-positive mothers by nested polymerase chain reaction (PCR) and subsequently subjected to direct sequencing. The sequences obtained were translated into the corresponding amino acids and compared to amino acid sequences of HBV subtype adr. All infants under investigation had received recombinant hepatitis B vaccine within 24 hours after delivery and had completed the recommended vaccination course, consisting of three to four doses administered at defined intervals.

RESULTS

The usual divergence regarding genotype and subtype was identified among the 11 samples tested. Only two exhibited a point mutation within the a determinant, one of which consisted of a substitution of glycine with alanine at position 145, and the other of a substitution of glutamine with arginine at position 129.

CONCLUSION

Eleven neonates were positive for HBV infection, and two of them showed point mutations that might have rendered the virus resistant to the vaccine, possibly due to a change in the S protein's secondary structure. Yet, this remains a matter of speculation, since the other seven cases positive for hepatitis B viral DNA merely demonstrated the usual genotype and subtype. The presence of escape mutants of HBV can be considered rather negligible with respect to vaccination programs, especially as the vaccine has been shown to reduce hepatitis B, as well as hepatocellular carcinoma efficiently.

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 hepatitis G virus infection in multiply transfused children with thalassaemia

We investigated the prevalence of hepatitis G virus (HGV) RNA in relation to the frequency of blood transfusions in thalassaemic children and in volunteer blood donors in Thailand. Furthermore, we studied the frequency of coinfection with hepatitis B virus (HBV) and/or hepatitis C virus (HCV) as well as a possible relationship to the alanine aminotransferase (ALT) status of the blood samples, taken at random from thalassaemic children who have received multiple blood transfusions and from volunteer blood donors. The results show detectable HGV-RNA in 32.6% of transfusion patients and in 5% of blood donors. The prevalence of HGV-RNA peaked between the 11th and 50th transfusion. The relationship between HGV infection and ALT status was not statistically relevant.

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.

Prevalence of infection with hepatitis G virus among various groups in Thailand

Two research groups recently and independently, isolated a hepatotropic flavivirus from human sera. The two viruses, named GB virus C and hepatitis G virus (HGV), were subsequently discovered to represent the same virus, which was associated with acute and chronic hepatitis of the non-A-E type. The prevalences of infection with HGV have now been investigated in various groups of the Thai population, some of which [e.g. thalassaemic children, patients with chronic liver disease, carriers of antibodies to hepatitis B virus and/or hepatitis C virus (HCV), prostitutes and intravenous-drug users (IVDU)] were assumed to be at high risk. Samples of sera were investigated by reverse-transcriptase PCR, using four primers created from the 5' untranslated region of HGV. The prevalence of HGV infection among the healthy controls (1%-5%) was found to be much less than that among thalassaemic children (32.6%), asymptomatic carriers of anti-HCV (20.4%), IVDU (18.2%), aplastic anaemia patients (14.3%) and prostitutes (10%), although similar to that in patients with chronic liver disorders. These results confirm a parenteral route of transmission for HGV and emphasise the need for further research to determine the clinical significance of this virus.

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.