Adding interferon to lamivudine enhances the early virologic response and reversion of the precore mutation in difficult-to-treat HBV infection.

BACKGROUND: The virologic impact of adding interferon to antiviral nucleoside therapy was studied in Japanese patients having perinatally transmitted hepatitis B virus (HBV) genotype C. METHODS: Sixty-four patients including 41 positive for hepatitis B e antigen (HBeAg) were assigned to receive either (1) a combination of interferon-alpha (6 million units daily for 2 weeks, then three times weekly) plus lamivudine (100 mg daily) for 24 weeks followed by lamivudine alone for 28 weeks (n = 30) or (2) 52-week lamivudine monotherapy (n = 34). RESULTS: The combination treatment enhanced the early virologic response, and HBV clearance was more frequent at week 8 for patients with baseline HBV DNA < or = 7 log copies/ml (90% vs. 33%, P = 0.013) and at week 24 for patients with baseline HBV DNA > 7 log copies/ml (75% vs. 40%, P = 0.080). In the combination arm, YMDD mutants emerged less often at week 52 (8% vs. 30%, P = 0.047). However, reversion of the precore mutation was more prominent with combination treatment than with monotherapy (McNemar test, P = 0.014 and P = 0.103, respectively). HBeAg seroconversion (P = 0.429) and sustained off-treatment HBV suppression to < or =5 log copies/ml (log-rank test, P = 0.195) were not improved. CONCLUSIONS: Simultaneous commencement of treatment with interferon and a nucleoside analog may be worthy as a treatment option to augment the early virologic response and prevent drug resistance in difficult-to-treat patients. Combination treatment was also shown to enhance reversion of the precore mutation. Further studies are warranted to clarify the therapeutic implications of this phenomenon.

New combination test for hepatitis C virus genotype and viral load determination using Amplicor GT HCV MONITOR test v2.0.

AIM: To develop a new sensitive and inexpensive hepatitis C virus (HCV) combination test (HCV Guideline test) that enables the determination of HCV genotypes 1, 2 and 3, and simultaneous determination of HCV viral load using commercial Amplicor GT HCV MONITOR test v2.0 (microwell version). METHODS: The HCV Guideline test used the PCR product generated in commercial Amplicor GT HCV Monitor test v2.0 for viral load measurement using microwell plate version of Amplicor HCV Monitor and also captured on separate plates containing capture probes and competitive oligonucleotide probes specific for HCV genotypes 1, 2 and 3, The HCV genotype was subsequently determined using the biotin-labeled PCR product and five biotin-labeled HCV-specific probes. RESULTS: The sensitivity of the HCV Guideline test was 0.5 KIU/mL. Specificity of the HCV Guideline test was confirmed by direct sequencing of HCV core region and molecular evolutionary analyses based on a panel of 31 samples. The comparison of the HCV Guideline test and an in-house HCV core genotyping assay using 252 samples from chronic hepatitis C patients indicated concordant results for 97.2% of samples (59.5% genotype 1, 33.7% genotype 2, 6.0% genotype 3, and 0.8% mixed genotypes). Similarly, the HCV Guideline test showed concordance with a serological test, and the serological test failed to assign any serotype in 12.7% of the samples, indicating a better sensitivity of the HCV Guideline test. CONCLUSION: Clinically, both viral load and genotypes (1, 2 and 3) have been found to be major predictors of antiviral therapy outcome regarding chronic hepatitis C based on guidelines and they are, in normal circumstances, performed as separate stand-alone assays. The HCV Guideline test is a useful method for screening large cohorts in a routine clinical setting for determining the treatment regimen and for predicting the outcome of antiviral therapy of chronic hepatitis C.

Long-term clinical and virological outcomes of chronic hepatitis C after successful interferon therapy.

Clinical relevance of occult hepatitis C virus (HCV) and/or hepatitis B virus (HBV) infection(s) remains uncertain years after interferon (IFN) therapy for chronic hepatitis C. By 1993, 38 sustained virological responders (SVRs) showing HCV RNA clearance at 6 months post-treatment and 37 biochemical responders (BRs) with end-of-treatment alanine aminotransferase (ALT) normalization and subsequent 6-month stabilization within 2 x the upper limit of normal (ULN) were enrolled. They were monitored for 4.4-12 years (median 6.8), then 15 SVRs and 15 BRs underwent paired liver biopsies. Biopsy samples were tested for positive and negative HCV RNA strands, and HBV DNA surface and X sequences. All SVRs showed sustained serum HCV RNA clearance during follow-up, but hepatocellular carcinoma (HCC) developed in 4 (11%) SVRs. On paired liver biopsies, histological improvement was significant, but mild inflammation persisted in 87% of SVRs. Nonetheless, no HCV RNA sequence was amplified from liver tissues, and HBV DNA sequences were found in only one SVR. As for BRs, biochemical flare-up of >2 x ULN occurred at a 5-year risk of 41% (95% CI 24.7-56.4). The event was unpredictable but controllable by retreatment in 70%. Liver tissues after follow-up contained positive and negative HCV RNA strands, but no HBV DNA sequence was amplified. These results suggest that SVRs, albeit free of occult HCV and/or HBV infection(s) over a decade, retain mild liver inflammation and the risk of HCC. Occult HBV was also shown uninvolved in flare-up during follow-up of BRs.

Differential alternative splicing expressions of telomerase reverse transcriptase in gastrointestinal cell lines.

Telomerase is a cellular RNA-dependent DNA polymerase that serves to maintain the tandem arrays of telomeric TTAGGG repeats at eukaryotic chromosome ends. One of the human telomerase components is hTERT, which has three alternative spliced sites that introduce eight isoforms of hTERT mRNA. The expression of these isoforms in gastrointestinal cell lines is unknown. We developed a PCR-based assay for detecting these splicing variants. In gastric and hepatocellular carcinoma cell lines, the gamma deletion variant and its combination variants, alpha- and gamma-, beta- and gamma-, and alpha-, beta- and gamma-deletion variants were frequently detected, while they were not detected in colorectal carcinoma cell lines. Our results provide important information of use for more detailed studies on the regulation of telomerase activity.

Genetic detection for hematogenous micrometastasis in patients with various types of malignant tumors using Uroplakin II derived primers in polymerase chain reaction.

The presence of circulatory metastasis is one of the most significant factors for poor-prognosis in patients with several types of cancer. To establish a sensitive reverse transcription PCR assay to detect micrometastasis in blood containing several cancer types, we first investigated Uroplakin II (UP II), a novel molecular marker for human transitional cell carcinoma of the bladder, in 25 types of normal organs. In our study, UP II mRNA was detected in 10 types of organs, including bladder, kidney, lung and pancreas, but was not detected in normal lymph nodes or leukocytes. The data indicated evidence of UP II expression in various types of normal tissues by RT-nested PCR analysis. UP II mRNA was detected in 2 of 11 (18.2%) peripheral blood samples from lung cancer patients with no metastasis, and in 5 of 12 (41.7%) peripheral blood samples of lung cancer patients with metastasis. UP II was also detected in 6 of 16 (37.5%) peripheral blood samples of patients with pancreatic cancer. The data are particularly important in that the molecular detection of micrometastasis in the blood by means of UP II mRNA identification is feasible for UP II-positive neoplasms, including lung and pancreatic cancers.

Novel alternatively spliced variant with a deletion of 52 BP in exon 6 of the progesterone receptor gene is observed frequently in breast cancer tissues.

The human progesterone receptor (PR) is a ligand-activated nuclear transcription factor that mediates progesterone action in target tissues. We found a novel alternatively spliced variant (ASV) of the PR mRNA in breast cancer tissues. The deleted transcript was characterized by an out-of-frame deletion of 52 bp in exon 6 (PR delta6/2 ASV). The PR delta6/2 ASV mRNA results in a partial defect in the region of the ligand-binding domain of the hormone receptor, where conserved residues are missing from the core of the protein. To clarify the clinical significance of the PR delta6/2 ASV, we investigated the expression of this ASV in noncancerous and cancerous tissues from patients with breast cancer using RT-PCR. The novel PR delta6/2 mRNA was detected in 24 of 39 (61.5%) cancerous tissues and in 3 of 39 (7.7%) noncancerous tissues from patients with breast cancer. PR delta6/2 ASV mRNA was expressed more frequently in breast cancer tissues than in noncancerous tissues (p < 0.0001), which suggests a possible relationship between the expression of PR delta6/2 and breast cancer. Our observations may provide a novel strategy for the genetic diagnosis of breast cancer.

Long-term histologic and virologic outcomes of acute self-limited hepatitis B.

The long-term impact of acute self-limited hepatitis B on the liver is unknown. Fourteen patients were recalled at a median of 4.2 years (range, 1.8-9.5 years) after the onset of acute hepatitis B. All showed clinical and serologic recovery with circulating hepatitis B surface antigen (HBsAg) clearance. Antibody to HBsAg (anti-HBs) had developed in 12 patients. Nine underwent liver biopsies at a median of 7.2 years, and histologic findings were evaluated using Ishak scores. Serum samples and frozen liver tissue were subjected to real-time detection polymerase chain reaction (PCR) to quantify the surface and X regions of the hepatitis B virus (HBV) genome and qualitative PCR to detect the covalently closed circular (ccc) HBV DNA replicative intermediate. Three patients had low levels of circulating HBV DNA up to 8.9 years after the onset, whereas both HBV DNA surface and X regions were found in the liver of all 9 patients examined, including 7 negative for serum HBV DNA. Liver viral loads assessed by the 2 regions showed a significant correlation (r = 0.946; P =.008), and all patients tested positive for ccc HBV DNA. Liver fibrosis and mild inflammation persisted in 8 patients. The fibrosis stage had relation to peak serum HBV DNA in the acute phase (P =.046) but not to liver viral loads in the late convalescent phase. In conclusion, occult HBV infection persists in the liver and is accompanied by abnormal liver histology for a decade after complete clinical recovery from acute self-limited hepatitis B.

Differential alternative splicing expressions of thymidylate synthase isoforms.

We identified two novel deletion variants of the thymidylate synthase transcript in gastric cell lines. Sequence analyses indicate that none of these variants results in introduction of a premature stop-codon or a frame shifts. In 39 gastric cancer samples, both the full-length and one-deletion variant messages were detected in cancerous as well as non-cancerous tissues. However, another isoform was found in only seven of 39 cancerous tissues. Our results provide important information to assist more detailed studies on the regulation of thymidylate synthase activity.

Expression of a novel splicing variant deleting exons 4 and 6 of the progesterone receptor gene is a rare event in breast cancer.

We identified a novel alternatively spliced isoform of PR mRNA in breast cancer tissues. The deleted transcript was characterized by an out-of-frame deletion of 437 bp, corresponding to the complete loss of exons 4 and 6 (PR delta4+6 ASV). PR delta4+6 ASV will result in a partial defect in the region of the ligand-binding domain of hormone receptors, suggesting that the conserved residues are missing from the core of the protein. In the limited number of samples studied, a novel PR delta4+6 mRNA was detected in 1 of 45 (2.2%) non-cancerous tissues of patients with breast cancer, in 5 of 45 (11.1%) cancerous tissues of patients with breast cancer. Loss of both exons 4 and 6 will be induced by incomplete splicing and/or repair mechanism. Further studies are necessary to establish the biological significance of this alternative splicing. The expressions of ASVs that induced the mimic PR transcripts need to be considered when designing strategies for regulation analysis of the PR gene.

Histological improvement of chronic liver disease after spontaneous serum hepatitis C virus clearance.

The long-term histological and virological outcomes of spontaneous circulating hepatitis C virus (HCV) clearance were studied in chronic liver disease. Between 1979 and 1984, three patients underwent laparoscopy for chronic non-A, non-B liver disease, and two were found to have cirrhosis and one with chronic active hepatitis. After HCV assays became available in 1990, they were positive persistently for HCV antibody without serum HCV RNA. Reductions of antibody levels to HCV core and/or nonstructural proteins were observed, and liver biopsies were undertaken between 1995 and 2000. Liver biopsies at 11-19 years after laparoscopy disclosed marked alleviation of liver inflammation and fibrosis in each case although a low grade of inflammation remained. The two patients with cirrhosis no longer showed histological features of cirrhosis, and the poor liver function in one patient had been ameliorated. Liver specimens from two patients were subjected to polymerase chain reaction to detect positive and negative HCV RNA strands and hepatitis B virus DNA. Only the positive HCV RNA strand was detected for one patient who had previously cirrhosis. Liver specimens were examined from another six nonviremic HCV-seropositive individuals without chronic liver disease. Five patients displayed low-grade liver inflammation without evident fibrosis, but none had any viral genome in the liver. These findings suggest that spontaneous circulating HCV clearance in chronic liver disease confers favorable liver histological outcome, although occult HCV infection persists. J. Med. Virol. 69:41-49, 2003.

Detection of circulating prostate tumor cells: alternative spliced variant of PSM induced false-positive result.

RT-nested PCR has been introduced as a highly specific and sensitive assay method to detect the prostate-specific membrane antigen (PSM) mRNA in peripheral blood. However, appreciable percentages of false-positive cases have been reported. Additionally, primer sets reported previously could not discriminate between PSM and PSM', an alternatively spliced variant, mRNA. These isoforms can be produced from a single gene. Switches in alternative splicing patterns are often controlled with strict cell-type or developmental-stage specificity. Therefore, it is most important to discriminate between PSM mRNA and PSM' mRNA. Using our highly specific primer sets, PSM mRNA was detected in 3 of 24 peripheral blood samples of normal male volunteers (12.5%) and was not detected in peripheral blood of 11 normal female volunteers. PSM' mRNA was detected in 5 of 24 peripheral blood samples of normal male volunteers (20.8%) and in 4 of 11 of normal female volunteers (36.4%). PSM' mRNA induced false-positive results, it is important for genetic diagnosis of prostate cancer to discriminate between PSM and PSM' using our primer sets with high specificity. The advances in the uniquely designed primer sets may allow researchers to detect a real PSM mRNA without PSM' mRNA.

Japanese familial hypercholesterolaemia with a 327insC mutation in the LDL receptor gene.

Mutations in the LDL receptor (LDLR) cause familial hypercholesterolaemia (FH) in an autosomal dominant manner. The condition frequently progresses to coronary atherosclerosis. We describe a patient with FH, but without ischaemic heart disease, who had a novel frameshift mutation (327insC) in exon 4 of the LDLR gene. This mutation introduced a premature termination codon (TGA, codon 158). The patient was a 59-year-old man who had presented with hypercholesterolaemia and a plasma total cholesterol (TC) concentration of 12.2 mmol/L at age 44 years. The mutation 327insC in this patient was heterozygous and hypercholesterolaemia was common within his family. Despite taking lipid-lowering medications (probucol and pravastatin) for more than 20 years, his TC concentration hardly fell below 7.8 mmol/L. However, neither the patient nor anyone else in his family developed characteristic symptoms of ischaemic heart disease or xanthoma. This patient was discovered by an intensive mutation survey among 22 unrelated Japanese with FH mainly in the Kanto area of Japan, suggesting a low incidence of the mutation in the area.

Expression of molecular marker genes in various types of normal tissue: implication for detection of micrometastases.

Many researchers have investigated the expressions of candidates for a suitable reverse transcription nested polymerase chain reaction (RT-PCR) marker. But typically biomarkers often have false-positive results. We assessed whether epidermal growth factor receptor (EGFR), carcinoembryonic antigen (CEA) and prostate-specific membrane antigen (PSM) could be detected in 28 different types of normal human sources. Using RT-nested PCR assay, EGFR mRNA was also detected in various types of normal tissue, including pancreas, prostate and uterus. CEA was detected in various types of normal tissue, including prostate, uterus, bladder and spleen. PSM mRNA was also detected in various types of normal tissue, including kidney, liver, skeletal muscle, spleen, bladder and ovary. We report here that the expression of these biomarkers in normal cells might have induced false-positives, and that further enhancement of sensitivity might compromise specificity. Conversely, these biomarkers can be utilized for attempts to define micrometastases in various types of tumors whose cells express these tissue-specific genes.

[External quality assessment of the genetic testings for hematopoietic tumor, CML].

Genetic testings are commonly employed in various fields of clinical medicine and the test items performed at clinical laboratories are increasing rapidly in number. They are utilized to make early and/or definite diagnoses of infectious diseases, leukemia, cancers and molecular inherited diseases and also to monitor the progress of the diseases. However, these genetic testings except for infectious diseases have been developed independently at each clinical laboratory and the test results obtained at each laboratory are not always compatible each other. Under these situations it is widely expected to construct advanced genetic testing systems that can supply standardized data at any of domestic and international clinical laboratories. For the period from April, 1999 to March, 2002 three major clinical laboratories, SRL, Inc., BML, Inc. and MBC, Inc., were consigned by JBA (Japan Bioindustry Association) to collaborate in standardizing the evaluation methods for genetic testing systems among the clinical laboratories. The aim of the study is to develop the standardized genetic testing systems and to propose them as international standard operational procedures to the ISO/TC212 working group. Although one of the most important issues for standardization is the external quality assessment, they have not been carried out in reality. In this study we evaluated the difference of the genetic testing results obtained during the year of 2000 and 2001 among the clinical laboratories. The genetic testings for hematopoietic tumor, CML were selected to be evaluated since they are widely accepted as clinically useful tests.