Molecular epidemiology and genetic history of hepatitis C virus subtype 3a infection in Thailand

OBJECTIVE

Among all hepatitis C virus (HCV) infections, subtype 3a is the most common genotype in Thailand. This study investigates the molecular epidemiology and epidemic history of HCV subtype 3a in Thailand.

METHODS

Three hundred and fifty-six serum samples were collected from HCV-infected Thai patients. The virus was isolated, after which the core and NS5B regions were sequenced. Subsequently, the HCV genotype was classified by phylogenetic analysis based on the core and NS5B regions. Molecular evolution analysis of HCV subtype 3a was estimated using BEAST (Bayesian Evolutionary Analysis by Sampling Trees) v.1.5.4.

RESULTS

Based on our phylogenetic analyses, subtype 3a (38.5%) was the most prevalent, followed by 1a (21%), 1b (13.8%), genotype 6 (19.9%) [comprised of subtypes 6e (0.3%), 6f (11%), 6i (1.9%), 6j (1.9%) and 6n (4.8%)] and 3b (5.6%). Our phylogenetic tree indicates the existence of a specific group of HCV subtype 3a strains in the Thai population. Molecular evolutionary analysis dated the most recent common ancestor of the Thai HCV subtype 3a strains as existing approximately 200 ago, and a Bayesian skyline plot showed that this particular strain spread to Thailand during the mid-1970s and early 1980s. This period overlaps with the Vietnam War (1955-1975) and the widespread use of injection stimulants introduced by the US Army during this time.

CONCLUSION

The estimated history of HCV subtype 3a infection in Thailand may help to predict the future burden of HCV-related diseases and facilitate better public health control and surveillance.

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.

Entire genome characterization of Chikungunya virus from the 2008-2009 outbreaks in Thailand

The resurgence of Chikungunya virus (CHIKV) in the southern, northeastern and northern parts of Thailand, inflicting approximately 46,000 reported cases since October 2008 until December 2009, has raised public health concerns. In the present study, we characterized nearly complete genome sequences of four CHIKV isolates obtained from 2008 to 2009 outbreaks in Thailand. Phylogenetic analysis was performed to determine the relationships of the study viruses with previously reported isolates. Results showed that 2008-2009 Thailand isolates belonged to the East, Central and South African genotype and were most closely related to isolates detected in Malaysia and Singapore in 2008. This was in contrast to isolates from all previous outbreaks in Thailand which were caused by an Asian genotype. We describe several novel mutations in Thailand isolates that warrants further investigation on characterization of CHIKV from different parts of the country to better understand the molecular epidemiology of Chikungunya fever outbreaks in Thailand.

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.

Molecular characterization of Hepatitis A virus causing an outbreak among Thai navy recruits

Hepatitis A virus (HAV) infection is a communicable disease, typically transmitted by faecal-oral contamination. HAV outbreaks usually occur in endemic areas. We report an outbreak of HAV from June to July, 2008 among Thai navy recruits who had received training at the Sattahip Navy Base, Chonburi province, Thailand. Upon conclusion of the training, the recruits were deployed to serve at several navy bases across the country. Secondary cases of HAV infection were reported among military personnel from these navy bases. To elucidate origin and distribution of these outbreaks, we characterized the genome and genotype of HAV isolated from the different navy bases. Sera and stool from the subjects were tested for antiHAV IgM, antiHAV IgG and HAV RNA. Subsequently, molecular characterization of HAV was performed by nucleotide sequencing of the VP1-P2A region, BLAST/FASTA and phylogenetic analysis. HAV RNA was detected in specimens obtained from different areas. All isolated strains clustered in the same lineage and belonged to genotype 1A. They shared nearly 100% genome homology indicating a single point source of this outbreak. This study provides essential baseline data as a reference for genetic analysis of HAV strains causing future outbreaks. Early detection of HAV infection and identification of the source by using molecular characterization and prompt preventive measures will hopefully prevent further outbreaks.

Serum transforming growth factor-beta1 and epidermal growth factor in biliary atresia

BACKGROUND AND AIM

Biliary atresia (BA) is a serious liver disease in children. Since transforming growth factor-beta1 (TGF-beta1) and epidermal growth factor (EGF) are involved in the hepatic reparative process, our objective was to investigate whether serum TGF-beta1 and serum EGF levels were associated with therapeutic outcomes in BA.

METHODS

Serum levels of TGF-beta1 and EGF were determined with the ELISA method in 67 postoperative BA patients with a median age of 7 years and in 10 age-comparable healthy children. The BA patients were then divided into two groups depending on their therapeutic outcome: good outcome (jaundice-free) and poor outcome (persistent jaundice). Clinical data, serum TGF-beta1 and serum EGF levels were compared between the two groups of BA patients. Correlation analysis of serum TGF-beta1 with serum EGF was carried out. Data are expressed as mean +/- SD.

RESULTS

Serum TGF-beta1 levels of BA patients were higher than those of controls (86.6 +/- 15.7 vs. 75.7 +/- 8.8 ng/ml, p = 0.0362). However, there was no difference in serum EGF between BA patients and controls (133.1 +/- 66.6 vs. 125.4 +/- 88.9 pg/ml, p = 0.744). Further subgroup analysis showed that patients with good outcomes (n = 40) had higher serum TGF-beta1 and serum EGF levels than patients with poor outcomes (TGF-beta1: 91.2 +/- 16.5 vs. 79.6 +/- 11.7 ng/ml, p = 0.002; EGF: 148.5 +/- 65.0 vs. 110.3 +/- 63.4 pg/ml, p = 0.02). In addition, serum TGF-beta1 was positively correlated with serum EGF (Pearson's r = 0.3418, p = 0.0046).

CONCLUSION

Elevated serum TGF-beta1 and serum EGF levels were associated with a good outcome in BA patients. There was a positive correlation between serum TGF-beta1 and serum EGF. This suggests that the resultant TGF-beta1 and EGF pathways may be involved in the pathophysiological process in postoperative BA.

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.

Elevated serum soluble E-selectin is associated with poor outcome and correlated with serum ALT in biliary atresia

BACKGROUND AND AIM

Biliary atresia (BA) is a serious liver disease. Our objective was to investigate possible roles of serum soluble E-selectin (sE-selectin) in BA.

METHODS

During their annual follow-up, the serum levels of sE-selectin were determined by ELISA in 53 postoperative BA patients and 10 healthy children. The patients were categorized into two groups according to their jaundice status. Comparisons of demographic data and serum sE-selectin levels between jaundice-free patients and jaundice patients were performed. Correlation analysis was carried out of serum E-selectin with serum ALT and serum GGT. Data are expressed as mean and SD (ng/mL).

RESULTS

The serum sE-selectin of BA patients was higher than that of controls (114.1 +/- 44.0 vs. 88.7 +/- 22.2; p = 0.01). Further subgroup analysis showed that there was an increase in serum sE-selectin levels of BA patients with jaundice (n = 21) compared to those without jaundice (n = 32) (129.7 +/- 48.6 vs. 103.9 +/- 38.1; p = 0.035). Also, serum E-selectin was positively correlated with serum ALT, a marker for liver injury (Pearson r = 0.355, p = 0.009), but not with serum GGT (Pearson r = 0.223, p = 0.12).

CONCLUSION

Elevated serum sE-selectin was associated with a poor outcome of BA. There was a positive correlation between serum sE-selectin and serum ALT. E-selectin probably plays a role in the pathophysiology of liver injury in postoperative BA.

Rapid detection and strain identification of porcine reproductive and respiratory syndrome virus (PRRSV) by real-time RT-PCR

AIMS

To develop and validate assays based on real-time reverse transcriptase-polymerase chain reaction (RT-PCR) for rapid detection and strain identification (European and North American strains) of porcine reproductive and respiratory syndrome virus (PRRSV) by using SYBR Green I and TaqMan probe chemistries.

METHODS AND RESULTS

This study describes two alternative assays based on real-time RT-PCR for rapid detection and strain identification of PRRSV in comparison with conventional RT-PCR. The first assay utilized SYBR Green I with melting curve analysis; another assay was performed using strain-specific TaqMan probes. Primers were selected from the conserved regions within ORF7 (N) of both strains whereas two TaqMan probes labelled with different fluorescent dyes were specifically designed for each strain. The result of strain identification was confirmed by direct sequencing. Both assays can be used for rapid detection and strain identification of PRRSV with a sensitivity of 10(4) and 10(3) copies microl(-1) for SYBR Green and TaqMan probe, respectively.

CONCLUSIONS

Real-time RT-PCR is a powerful method combining rapidity, specificity and efficiency for large-scale screening and strain identification of PRRSV.

SIGNIFICANCE AND IMPACT OF THE STUDY

The data indicate that the methods developed are invaluable for detecting low levels of PRRSV infection in swine.

Genetic analysis of influenza A virus (H5N1) derived from domestic cat and dog in Thailand

Complete genome sequences of H5N1 viruses derived from a domestic cat "A/Cat/Thailand/KU-02/04" and dog "A/Dog/Thailand/KU-08/04" were comprehensively analyzed and compared with H5N1 isolates obtained during the 2004 and 2005 outbreaks. Phylogenetic analysis of both cat and dog viruses revealed that they are closely related to the H5N1 viruses recovered from avian influenza outbreaks of the same period. Genetic analysis of 8 viral gene segments showed some evidence of virulence in mammalian species. In summary, the H5N1 viruses that infected a domestic cat and dog are highly pathogenic avian influenza viruses that are virulent in mammalian species, potentially indicating transmission of H5N1 viruses from domestic animals to humans.

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.

Characterization of the hemagglutinin and neuraminidase genes of recent influenza virus isolates from different avian species in Thailand

The hemagglutinin (HA) and neuraminidase (NA) genes of eight influenza A virus (H5N1) isolates obtained from various avian species in Thailand in 2003-2004 have been characterized in comparison with the Thai isolate A/Chicken/Nakorn-Pathom/Thailand/CU-K2/04(H5N1). Phylogenetic analyses of both genes revealed that all the eight avian isolates were closely related to the A/Chicken/Nakorn-Pathom/Thailand/CU-K2/ 04(H5N1). The amino acid sequence of the HA cleavage site revealed a common characteristic of a highly pathogenic virus strain. Moreover, a deletion of 20 amino acids in the NA stalk region was detected in all Thai isolates in contrast to the H5N1 strain that had caused outbreaks in eastern Asia in 1996-1997 and 2000-2001.

Nucleotide sequence analysis of nucleocapsid protein gene of canine distemper virus isolates in Thailand

The C-terminal part of the nucleocapsid protein gene of 13 canine distemper virus (CDV) isolates from Thailand, were analyzed. The nucleotide sequences were assigned to two clusters; cluster A exhibited a high degree of homology with the vaccine strain Onderstepoort, 99.10 and 97.61%, respectively, in the two isolates examined. Cluster B appeared closely related to virulent strains registered in the GeneBank database and to the virulent reference strain (A75/17); a total of 11 samples were analyzed, with 94.63-99.10% homology at the same position. The deduced amino acid sequences correlated with the two-nucleotide sequence clusters. However, there was no association among the CDV groups with histories of vaccination, sex, ages, clinical findings and evidence of viral antigen in tissues.

Hepatitis C virus infection in Thai patients with oral lichen planus

OBJECTIVE

Many studies focusing on the association between hepatitis C virus (HCV) infection and oral lichen planus (OLP) have been conducted. Diversities of geographical locations could be a major factor influencing the prevalence of HCV. This study was aimed to define whether there was a relationship between the OLP and HCV infection in Thailand.

MATERIALS AND METHODS

Serum samples of 60 patients (with OLP) and 60 controls (without OLP), whose age and gender were matched, were respectively screened for anti-HCV by ELISA (third generation), and reverse transcription polymerase chain reaction (RT-PCR) for HCV-RNA.

RESULTS

We found five patients (8.33%) with OLP infected with HCV: three patients were positive for both anti-HCV and HCV-RNA; one patient was only positive for anti-HCV; and one patient was only positive for HCV-RNA; whereas all the controls were negative for both anti-HCV and HCV-RNA (P=0.029). Three of five cases of OLP with HCV infection had histories of blood transfusions over 10 years ago.

CONCLUSION

The present study reports a small, but statistically significant high prevalence of HCV infection among patients with OLP, although the underlying mechanism still remains unknown.

Molecular characterization of Hepatitis C virus (HCV) core region in HCV-infected Thai blood donors

In order to investigate the distribution of Hepatitis C virus (HCV) genotypes in Thailand, we performed phylogenetic analysis based on the virus core region and in this way we identified and reliably distinguished HCV genotypes 1-6 as well as subtypes. Among 100 plasma samples randomly selected from blood donors positive for antibodies to HCV (anti-HCV) 90 (90%) were found positive for HCV RNA and 77 of them were subjected to nucleotide sequencing. The following types and subtypes were identified in this group: 1a in 16 samples (20.8%), 1b in 14 samples (18.2%), 3a in 29 samples (37.7%), 3b in 5 samples (6.5%), and 6a in 13 samples (16.9%). Although this study allowed identification and characterization of HCV among blood donors, more extensive studies are needed to explore the HCV distribution in other population groups and in other geographical regions and to exploit the virus core-based characterization of HCV for evaluation of treatment and clinical outcome and epidemiological purposes.

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.

Infection with hepatitis C virus among intravenous-drug users: prevalence, genotypes and risk-factor-associated behaviour patterns in Thailand

Hepatitis C virus (HCV) infection, a major problem worldwide, is usually transmitted parenterally or by use of contaminated needles among intravenous-drug users (IVDU). In a cross-sectional study, demographic data were collected and behaviour patterns investigated in interviews with 453, consenting IVDU. Blood samples were collected from each interviewee and checked for anti-HCV antibodies and, in a PCR-based assay, for the RNA of HCV. Almost all (92.5%) of the IVDU investigated were found positive for anti-HCV and/or the viral RNA. Most (73.5%) of those positive for HCV RNA were found to be infected with genotype 3a alone, the rest being infected with 1b (17.9%), 6a (3.5%), 3b (1.4%), 1a (1.0%), or both 3a and 6a (2.1%) or having non-typable infections (0.6%). Curiously, 26.0% of those who appeared seronegative for anti-HCV were positive for HCV RNA. The longer an interviewee had been using intravenous drugs, the more likely he or she was to be infected with HCV. Among the IVDU, the sharing of needles, syringes and/or other drug-related paraphernalia appeared to be the behaviour carrying the highest risk of HCV infection, giving an adjusted odds ratio and (95% confidence interval) of 4.84 (1.88-12.43). Programmes of needle and syringe exchange should probably be implemented among IVDU in Thailand and elsewhere, to slow the transmission of HCV.

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.

Clinical significance of p53 antigen and anti-p53 antibodies in the sera of hepatocellular carcinoma patients

BACKGROUND

To analyze the clinical significance of serum p53 protein and anti-p53 antibodies as serological markers for hepatocellular carcinoma (HCC).

METHODS

We studied clinical data, i.e., age, sex, etiology, serum alpha-fetoprotein (AFP) level. TMN staging, and Okuda staging in 141 patients with HCC. The sera of these patients were analyzed for serum p53 protein and serum anti-p53 antibodies by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Serum p53 antigen and serum anti-p53 antibodies were detected in the sera of 32 of the 141 (22.7%) patients and 26 of the 141 patients (18.4%), respectively. Of note, the HCC patients who were positive for p53 antigen (32/141) had no circulating anti-p53 antibodies. When both these groups of patients were combined as a serum p53 status-positive group, the total number in this group was 58 (41.1 %). Positive status of p53 was not associated with age (P = 0.206), serum alpha-fetoprotein level (P = 0.851). Okuda staging (P = 0.243), or survival (P = 0.078), but was correlated significantly with TMN staging (P = 0.049). Interestingly, a shorter survival time (mean, 3.9 months) was noted in the serum p53 status-positive group. in comparison with the longer survival time (mean, 6.5 months) in the serum p53 status-negative group.

CONCLUSIONS

Combination of the detection of serum p53 antigen and antibodies by ELISA may represent a suitable noninvasive investigation in assessing the clinical implications and prognoses of patients with HCC.

A case of Pfeiffer syndrome type 1 with an A344P mutation in the FGFR2 gene

Pfeiffer syndrome, an autosomal dominant disorder, consists of craniosynostosis, broadening of the thumbs and great toes, and partial soft tissue syndactyly of the hands and feet. Three clinical subtypes have been classified mainly for the purpose of genetic counseling. Mutations in FGFR1 and FGFR2 are known to be associated with the syndrome. However, the correlation between genotype and phenotype is not well defined. Only one patient with Pfeiffer syndrome with no other clinical information has been reported to have had an A344P mutation of the FGFR2. Here we report a Thai male patient with sporadic Pfeiffer syndrome type 1 with impaired intelligence (IQ = 77). Mutation analysis revealed A344P in FGFR2. Identification of the clinical features and molecular defects in more patients is required to better correlate the genotype and phenotype of this complex syndrome.

Predominant human rotavirus genotype G1P[8] infection in infants and children in Bangkok, Thailand

Human rotavirus is the major etiologic agent of infantile diarrhea on a worldwide scale. In this study, rotaviruses were detected by reverse-transcription PCR in 42 of 83 stool specimens from children below the age of 3 years with acute diarrhea in Bangkok, Thailand, between November 1998 and August 1999. G and P types of all samples were characterized by restriction endonuclease analysis (REA) and multiplex PCR typing assay, respectively. Strain G1P[8] (76.1%) was the predominant type, followed by G1P[6] (2.4%). Strain G1 combined with mixed P[8]/P[6] was identified in 2 specimens (4.8%) and 7 untypeable G strains (16.7%) were observed. This information on the circulating G and P combinations should be useful for understanding the epidemiology of human rotavirus in Bangkok, Thailand.

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.

Transfusion transmissible virus TTV and its putative role in the etiology of liver disease

TTV, the transfusion transmissible hepatitis virus infects mainly patients at risk for parenteral exposure and hence, prone to develop chronic liver disease, as well as healthy populations worldwide. Most TTV infections appear to occur parenterally, with viremia detected frequently in blood donors and blood products. The substantial proportion of asymptomatic individuals never exposed to blood-borne agents, and its high prevalence among healthy subjects implicates the fecal-oral route as another potential for transmission. According to the TTV DNA levels detected in liver tissue, it apparently replicates in hepatocytes, and TTV DNA is present in sera of patients with posttransfusion hepatitis of unknown etiology closely correlated with ALT levels. However, TTV initiating the development of chronic liver disease or causing posttransfusion hepatitis could not be confirmed, as most patients positive for TTV DNA remain asymptomatic and those progressing towards chronic liver disease are invariably coinfected with either the hepatitis B or C virus. Also, TTV coinfection does not aggravate the symptoms associated with hepatitis B or C. Similarly, it does not cause posthepatitis aplastic anemia, and high-risk patients can immunologically clear the viral DNA. In conclusion, being widely distributed and apparently nonpathogenic, TTV might represent an opportunistic but innocent virus reminiscent of hepatitis G virus, with a negligible role in the etiology of chronic liver disease.

Core promoter and precore mutants of hepatitis B virus: prevalence and clinical relevance in chronic hepatitis patients

The present study was conducted to determine prevalence and exact type, as well as nucleotide position of the precore/core mutations of hepatitis B virus found in Thai patients diagnosed with chronic hepatitis and/or cirrhosis in relation to the clinical parameters established with the respective patients. To that end, 24 HBeAg-positive and 56 HBeAg-negative individuals were selected at random from a cohort of altogether 256 chronic liver disease patients. DNA was extracted from their blood sera, amplified by polymerase chain reaction using semi-nested primers and subjected to direct sequencing. Clinically, the HBeAg-positive chronic hepatitis patients displayed significantly higher transaminase levels than those negative for HBeAg. Our results showed 2 of the 7 (28.6%) PCR-positive HBeAg-positive sera displaying double mutations in the core promoter region at position 1762/64. The nucleotide sequences obtained from the 24 PCR-positive HBeAg-negative sera revealed 18 (75%) mutations in the core promoter region (1762/64), and/or 7 (29.2%) mutations at position 1753, and/or 6 (25%) mutations of the start codon (1814), and/or 8 of (33.3%) nucleotide 1896 turning codon 28 into a stop codon and one sample (4.2%) displaying a deletion between nucleotides 1758-1772. It is suggested that the mutations observed have an impact on the DNA secondary structure in such a way that successful transcription of the HBeAg gene is rendered impossible. To what extent this mutation influences the severity of chronic liver disease remains to be elucidated.

Increasing susceptibility to HAV among members of the young generation in Thailand

The prevalence of antibodies to hepatitis A virus was studied in 961 children and adolescents, randomly selected from five different provinces in Thailand (Chonburi, Lopburi, Udonthani, Nakhon Si Thammarat and Lopburi). The highest prevalence was found in Nakhon Si Thammarat, with 32.1 percent of those aged 10-14 years and 57.1 percent of those aged 15-18 years showing evidence of protective immunity. However, this high rate could be explained by an outbreak of hepatitis A in 1992. In the remaining four provinces, the pattern was typically age-related in that all individuals showed between zero and 13 percent antibody prevalence until reaching the 15-to-18-year age group where it increased to between 5.6 and 22.7 percent. The overall sero-prevalence among all age groups was 7.9 percent. Thus, the majority of the younger generation is susceptible to hepatitis A virus infection thereby enhancing the impact, should an outbreak occur. Preventive measures that might be taken are education aimed at better hygiene and sanitation, as well as vaccination of susceptible individuals within high-risk populations.

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.

Clinical associations and prognostic significance of serum anti-p53 antibodies in Thai patients with hepatocellular carcinoma

Mutations of the p53 gene have been reported to be of prognostic significance in hepatocellular carcinoma (HCC). However, the clinical associations and prognostic value of anti-p53 antibodies, known to be products of the host immune response to these mutations, have been controversial. Serum anti-p53 antibodies were measured in 121 Thai patients diagnosed with HCC using a specific enzyme-linked immunosorbent assay (ELISA) kit. The clinical/pathological characteristics of the patients were compared with respect to the presence of serum anti-p53 antibodies. Cox regression analysis was performed to assess factor interaction and association with survival. Anti-p53 antibodies were detected in 13.2% (16 of 121) of our patients. There were no differences between groups with regard to age, sex, viral markers (HBsAg or anti-HCV), severity of liver disease and tumor advancement. The median survival rates for patients positive and negative for anti-p53 antibodies were 4.0 and 3.0 months, respectively (p = 0.443, by log-rank test). Multivariate analysis demonstrated that an advanced Okuda stage, lack of therapy and presence of portal vein thrombosis were independent factors related to the prognosis of the patients. Nonetheless, the presence of anti-p53 antibodies did not constitute a predictive variable associated with a poorer prognosis. Serum assay of anti-p53 antibodies, although rapid and easily performed, may not be suitable as an alternative to molecular detection of mutations in assessing tumor advancement and prognosis of patients with HCC.

Impact of hepatitis B immunisation as part of the EPI

Since 1992, hepatitis B vaccine has been an integrated part of Thailand's expanded programme on immunisation (EPI). Based on the data from five representative provinces, we have evaluated its impact on the countrywide prevalence of HBV infection and carrier rate. The population studied comprised 400-488 healthy and immuno-competent, subjects per area. The subjects' ages ranged from 6 months to 18 years. We examined their sera for viral hepatitis markers using commercially available test kits and established the coverage rate of hepatitis B vaccination after its inclusion into the EPI to be 71.2-94.3%. The number of individuals undergoing the complete course of vaccinations had increased four-fold. Consequently, only 0.7% of the children born after the implementation of this the novel EPI strategy were HBV carriers.

Parvovirus B19 antibodies in immunocompromized children in Thailand

Parvovirus B19, a non-enveloped single stranded DNA virus is distributed worldwide. Sero-prevalence in adult populations amounts to approximately 50%. Clinical manifestations vary depending on the Immune status of the infected individuals and may include mild childhood Infection as well as hydrops fetalis due to intrauterine infection. To determine the prevalence of this infection among the immunocompromized individuals in Thailand, we determined, by indirect ELISA, levels of IgM and IgG antibodies to the parvovirus B19 in 106 immunocompromized children. These included 49 children who were on chemotherapy for treatment of malignancies, 18 who were receiving immunosuppressive drugs after organ transplantations, 14 who were under a regimen of corticosteroids and 25 who were positive for antibodies to HIV. The average prevalence of IgG antibodies in 106 children was 16.0%; the prevalence of antibodies was 33.3% in post-transplanted group, 16% in children positive for HIV, 12.2% in the group receiving chemotherapy for malignancies and 7.6% in the group treated with corticosteroids. All children were negative for IgM antibodies to parvovirus B19.

Prevalence and clinical relevance of serum anti-p53 antibodies in patients with cholangiocarcinoma

Cholangiocarcinoma (CCA) constitutes carcinoma of the bile duct found at a high prevalence in northeastern Thailand. In the present study, we examined the sera of altogether 82 Thai CCA patients for the presence of anti-p53 antibodies in order to investigate a role of the tumor suppressor gene, p53 in the carcinogenesis. Our results revealed anti-p53 antibodies in 7.3% of the cases tested, which conforms to the prevalence rate of p53 gene mutation recently reported at 5% among Thai patients. With limited number of the patients, anti-p53 antibodies were rapidly detected more frequently among patients with peripheral tumors than those with central tumors. However, further studies is required to establish significance and prognostic value of the antibodies in the context of CCA.

Persistence of antibodies to the surface antigen of the hepatitis B virus (anti-HBs) in children subjected to the Expanded Programme on Immunization (EPI), including hepatitis-B vaccine, in Thailand

Will hepatitis-B vaccine administered at birth, and at 2 and 6 months of age, as an integral part of Thailand's Expanded Programme on Immunization, provide long-term protection? In an attempt to answer this question, residents of five provinces (representing five distinct geographical areas of Thailand) who were aged 1-10 years and had received this course of vaccination were enrolled on a serological study. Each was tested, with ELISA, for the surface antigen of hepatitis B (HBsAg) and for antibodies against this antigen (anti-HBs) or against the core antigen (anti-HBc). Over all age-groups, the prevalences of HBsAg, anti-HBs and anti-HBc were 0.67%, 71.4% and 5.5%, respectively. Although the prevalence of anti-HBs decreased with age, it remained at 56%-65% among those aged 6-10 years. Between 2% and 17% of the subjects aged 1-9 years had high titres of anti-HBs. Based on these results, an additional booster, still a controversial issue, does not appear to be required in order to prevent infection with hepatitis B virus and thus permit the eventual eradication of chronic carriage and its fatal sequelae in Thailand.

Serum interleukin-6 and interferon-gamma levels in patients with hepatitis B-associated chronic liver disease

Hepatitis B virus (HBV) infection can elicit a variety of clinical sequelae ranging from acute self-limited hepatitis to hepatocellular carcinoma, which are not attributable to a direct cytopathic effect of the virus but rather to the individual host's immune response. Cytokines, low-molecular-weight proteins with a broad range of activity, have been shown to be involved in the regulation of hepatocyte functions, as well as in the pathogenesis leading to liver damage. In the present study, we investigated the correlation between serum interleukin 6 (IL-6) and interferon gamma (IFN-gamma) in altogether 75 patients chronically infected with HBV. They comprised 15 asymptomatic carriers, 15 chronic persistent hepatitis (CPH) and 15 chronic active hepatitis (CAH) patients, 15 cases of cirrhosis and 15 patients with hepatocellular carcinoma (HCC) previously diagnosed by serology and histology, respectively. IL-6 and IFN-gamma levels in their sera were determined using a commercially available kit. Our results showed various concentrations of serum IL-6 detectable in 6.7% of asymptomatic carriers, 13.3% of patients with CPH, 20% of patients with CAH, 33.3% in cirrhotic patients and 66.7% in HCC. In contrast, serum IFN-gamma was only found in 13.3% of asymptomatic carriers and CAH, but could not be detected in the other groups. Our data demonstrated a positive correlation between serum IL-6 and clinical severity of chronic HBV infection, whereas the IFN-gamma levels appeared not to be correlated. From this we conclude that among chronic hepatitis patients IFN-gamma is mostly not expressed at a level detectable by serology, whereas according to other authors it is involved in the immediate immune response triggered by acute hepatitis. IL-6 on the other hand, might rather be responsible for liver inflammation and regeneration in chronic liver disease.

Prevalence of antibodies to parvovirus B 19 in Thailand

Infection with human parvovirus B 19, a single-stranded non-enveloped DNA virus of worldwide distribution, is rather common and displays a broad spectrum of clinical manifestations of varying severity, depending on the patient's immune response. As the target of infection are the erythroid precursor cells, patients can experience an aplastic crisis. Usually, at least in immunocompetent individuals, viremia ceases with the appearance of virus-specific antibodies in the patient's serum whereupon the patients retain lifelong immunity to reinfection. Since data as to the prevalence of this agent has not been established for Thailand, the purpose of the present study was to investigate its frequency among 3 distinct groups, comprising 30 healthy children. 64 children with acute unrelated illness, and 35 voluntary blood donors, respectively, by means of enzyme linked immunosorbent assay. Our results have shown that, as reported for other countries, anti-parvovirus IgG increases in an age-dependent manner and is established at an overall prevalence of 20.16%, inviting the conclusion that the local population is infected by this agent as frequently as those of other countries in the Far East. Further studies need to be undertaken in order to elucidate its prevalence among members of high-risk groups.

Prevalence of core promotor and precore mutants of hepatitis B virus in thailand by RFLP and sequencing

Hepatitis B virus has been known to frequently undergo mutations of its genome at various sites, mostly due to it employing a reverse transcriptase devoid of proofreading capacity in the course of its replication. The purpose of the present study has been to screen 257 HBsAg-positive chronic liver disease patients, more specifically 78 cases chosen at random out of those negative for HBeAg and 33 of the HBeAg-positive cases serving as controls for three discreet point mutations in the precore/core region of hepatitis B virus. To that end, HBV DNA extracted from sera was amplified by polymerase chain reaction (PCR) using semi-nested primers and subsequently subjected to restriction fragment length polymorphism (RFLP) analysis, 36 HBeAg-negative versus 30 HBeAg-positive sera, respectively, as well as to direct sequencing in some samples randomly selected to corroborate the RFLP results. Our results showed double mutations at positions 1762 and 1764 of the core promoter in between 25/36 (69.4%) and 19/25 (76%) of the sera tested, a missense mutation of the start codon in between 8/36 (22.2%), and 5/25 (20%) and a mutation turning codon 1896 into a stop codon in between 9/36 (25%) and 6/25 (24%) determined by RFLP and sequencing, respectively. These data indicate the double mutation at positions 1762 and 1764 to be the most prevalent among HBeAg-negative chronic hepatitis patients in Thailand whereas, in contrast to reports from other Asian countries, the mutation at nucleotide 1896 occurred in a mere 25%, while on the other hand the mutation abolishing the start of protein synthesis was observed to occur at a higher frequency than determined in several other geographical areas.

Cytomegalovirus infection in immunocompromised children in Thailand

Cytomegalovirus (CMV) constitutes the most widespread cause of congenital and perinatal viral infections on a global scale, exceeding a 90%-prevalence among blood donors in Thailand. The present study was aimed at determining the prevalence of CMV in the sera of 113 immunocompromised children by means of serology, as well as polymerase chain reaction using nested primers. Our results showed anti-CMV IgG, i.e. latent infection, prevalent in an age-dependent manner irrespective of the disorder underlying the children's immunocompromised condition, whereas anti-CMV IgM was equally prevalent throughout all age groups and disease patterns and, therefore, unreliable as a marker. Detection of serum CMV DNA by PCR represented the most exact diagnostic parameter by far, indicating active infection long before clinical symptoms may appear. In conclusion, based on the high prevalence of latent CMV infection among the general population in Thailand, we recommend especially the sera of immunocompromised patients be examined for the presence of viral DNA by means of PCR in order to provide clinical guidelines for their proper management.

Coinfections with hepatitis g and/or c virus in hepatitis B-related chronic liver disease

Concurrent infections with HGV and/or HCV (HGV/HCV) were investigated in 196 patients with HBV-related chronic liver disease (115 chronic hepatitis, 31 liver cirrhosis, 50 hepatocellular carcinoma), and in 100 HBsAg carriers. Coinfections were detected in 18 (9.2%) patients with HGV (10) or HCV (5) or both agents (3), but in none of the HBsAg carriers. Patients with coinfection were more frequently exposed to blood transfusions (55.6% vs 5.6%) and also were more commonly anti-HBe positive. Serum levels of HBV-DNA were lower in patients with HCV coinfection than in those coinfected with HGV. Interferon was administered to 39 patients with chronic active hepatitis including 7 patients with HGV/HCV coinfection. Sustained clearance of HBV-DNA was observed in 10 (25.6%) patients who were solely infected with HBV. These patients were significantly younger and had much lower histological scores than non-responders. Patients with HCV coinfection had significantly higher pre-treatment histological scores than those without HCV. After interferon treatment, a significant reduction in histological scores was observed in all patients except those coinfected with HGV/HCV. None of the 7 patients with coinfection had sustained clearance of HBV-DNA or HCV-RNA, and only one had cleared HGV-RNA. These results suggest that parenteral exposure is a risk factor for HGV/HCV coinfection in chronic HBV infection. HGV infection shows no significant impact on chronic HBV infection. HCV coinfection appears to inhibit HBV replication, but causes more severe chronic hepatitis and increases resistance to interferon therapy.

The predominant genotypes of hepatitis B virus in Thailand

In Thailand, chronic liver disease (CLD) as a consequence of infection with hepatitis B virus (HBV) constitutes a public-health burden. Control and treatment are complicated by the virus exhibiting an unusually high mutation rate, with some genotypes apparently causing more severe disease than others. Restriction-fragment-length-polymorphism (RFLP) analysis of the pre-S region of the viral genome, amplified by PCR, was used to determine which genotypes were most prevalent among Thai patients chronically infected with the virus. The patients were chronic HBV carriers (40) or cases of chronic hepatitis (34), cirrhosis (14) or hepatocellular carcinoma (30). As indicated by the results of earlier studies on CLD patients in South-east Asia, genotype C (68.6%) was clearly predominant. RFLP patterns permitted the C1 (12.7%), C7 (45.7%), C8 (10.2%) and B1 (29.7%) subtypes to be identified. Two samples that could not be typed by RFLP were analysed by direct sequencing, categorized as type C, and tentatively designated as subtype C9. As comparison of the present data with those previously obtained by direct sequencing of PCR products indicates that RFLP analysis is as specific and reliable as sequencing and less expensive and time-consuming, RFLP analysis may be particularly useful for epidemiological studies.