Clinical application and analysis of hepatitis C virus NS3 antigen detection by ELISA in human serum.

BACKGROUND: Hepatitis C virus (HCV) core antigen assays have been produced to exclude infectious donations collected during the preseroconversion window phase (PWP). For the same purpose, we evaluated the specificity and sensitivity of a novel hepatitis C virus NS3 antigen detection immunoassay and the application of this assay in clinical diagnosis. METHODS: Samples from 77 healthy subjects, 173 anti-HCV positive patients and 3708 hepatitis patients other than HCV positive were tested with the HCV NS3 antigen assay. Some HCV NS3 antigen positive samples were further validated with HCV-RNA, neutralization and immunodot assays. Twenty-five sequential samples from 11 HCV NS3 antigen positive patients were subjected to kinetic study. RESULTS: Only 48 (1.3%) of 3708 anti-HCV negative samples were positive for HCV NS3 antigen. Among them, 44 of 3030 samples from patients only infected with HBV were HCV NS3 antigen positive, 4 of the 445 samples from patients infected with other type hepatitis were HCV NS3 antigen positive. In addition, 42 (24.3%) of 173 anti-HCV positive samples were HCV NS3 antigen positive and all 77 samples from healthy subjects were negative to HCV NS3 antigen assay. Of the 15 HCV NS3 antigen positive samples, 9 (60%) were HCV-RNA positive. The neutralization and positive percentage of immunodot assay for 23 HCV NS3 antigen positive sera were 87.0% (20/23) and 69.6% (16/23) respectively. Of the 25 sequential samples from 11 HCV NS3 antigen positive patients, there was a negative correlation between the OD values and the duration of test (r = -0.989, P < 0.05), and there were correlations among their HCV NS3 antigen, HCV-RNA and anti-HCV titres. The anti-HCV antibodies of two sera were detected while their OD values of HCV NS3 antigen decreased gradually. CONCLUSIONS: The HCV NS3 antigen detection assay showed perfect specificity and high sensitivity. Thus, it would be useful and economical as a routine test in laboratories for early diagnosis of HCV infection and prevention.

[Detection of HCV antigen in the serum by immunodotting].

AIM: To set up a simple and rapid screening method of early detection for HCV infection. METHODS: The HRP-anti-HCV monoclonal antibodies (mAbs) conjugate was prepared by anti-HCV-core and anti-HCV-NS3 mAb with high specificity. HCV antigens in the sera from hepatitis patients and normal persons were detected by immunodotting and compared by double antibody ELISA and RT-PCR. RESULTS: The positive ratio for HCV antigen was 15.4% (8/52), 1.73% (19/1099) and 1.03% (1/97) in hepatitis C patients, hepatitis B patients and hepatitis NA-NE patients, respectively. The results for HCV antigen were negative in hepatitis A patients (0/81), hepatitis E patients (0/67) and normal persons (0/50). There was no significant difference among the immunodotting and double antibody ELISA and RT-PCR. There was definite correlation between the immunodotting and RT-PCR. CONCLUSION: This method, simple and rapid with high specificity, provides an effective way for the early diagnosis and routine detection of HCV.

RANTES gene single nucleotide polymorphisms and expression in patients with chronic hepatitis B virus infection.

BACKGROUND: Regulated on activation, normal T-cell expressed and secreted (RANTES) plays a critical role in T-lymphocyte activation and proliferation. The process is involved in both acute and chronic phases of inflammation. The present study was to ascertain the possible correlations between chronic hepatitis B virus (HBV) infection and the RANTES gene polymorphisms and their expression. METHODS: The study included 130 HBV negative healthy donors and 152 patients with chronic hepatitis B (CHB) virus infection. The polymerase chain reaction (PCR) and restriction fragment length polymorphisms (RFLPs) were used to detect RANTES gene single nucleotide polymorphisms (SNPs). RANTES levels in the platelet depleted plasma were detected by enzyme linked immunosorbent assay (ELISA). RESULTS: RANTES alleles -403G, -28C and In1.1T were the predominant alleles in the subjects studied. No significant correlation was found between CHB infection and the RANTES alleles, while a significant correlation was found between CHB infection and increased RANTES expression in platelet depleted plasma (P < 0.05). CONCLUSIONS: SNPs in RANTES gene do not affect chronic HBV infection or the outcome of interferon-alpha treatment in patients positive for HBV "e" antigen (HBeAg+). However, patients with CHB infection express the higher levels of plasma RANTES, which is thus associated with CHB infection.

Clinicopathological study on TTV infection in hepatitis of unknown etiology.

AIM: To investigate the state of infection, replication site, pathogenicity and clinical significance of transfusion transmitted virus (TTV) in patients with hepatitis, especially in patients of unknown etiology. METHODS: Liver tissues taken from 136 cases of non-A non-G hepatitis were tested for TT virus antigen and nucleic acid by in situ hybridization (ISH) and nested-polymerase chain reaction (PCR). Among them, TT virus genome and its complemental strand were also detected in 24 cases of autopsy liver and extrahepatic tissues with ISH. Meanwhile, TTV DNA was detected in the sera of 187 hepatitis patients by nested-PCR. The pathological and clinical data of the cases infected with TTV only were analyzed. RESULTS: In liver, the total positive rate of TTV DNA was 32.4% and the positive signals were located in the nuclei of hepatocytes. In serus, TTV DNA was detected in 21.4% cases of hepatitis A-G, 34.4% of non-A non-G hepatitis and 15% of healthy donors. The correspondence rate of TTV DNA detection between liver tissue with ISH and sera with PCR was 63.2% and 89.3% in the same liver tissues by ISH and by PCR, respectively. Using double-strand probes and single-strand probes designed to detect TTV genome, the correspondence rate of TTV DNA detected in liver and extrahepatic tissues was 85.7%. Using single-strand probes, TTV genome could be detected in liver and extrahepatic tissues by PCR, but its complemental strands (replication strands) could be observed only in livers. The liver function of most cases infected with TTV alone was abnormal and the liver tissues had different pathological damage such as ballooning, acidophilia degeneration, formation of apoptosis bodies and focus of necrosis, but the inflammation in the lobule and portal area was mild. CONCLUSION: The positive rate of TTV DNA among cases of hepatitis was higher than that of donors, especially in patients with non-A non-G hepatitis, but most of them were coinfected with other hepatitis viruses. TTV can infect not only hepatocytes, but also extrahepatic tissues. However, the chief replication place may be liver. The infection of TTV may have some pathogenicity. Although the pathogenicity is comparatively weak, it can still damage the liver tissues. The lesions in acute hepatitis (AH) and chronic hepatitis (CH) are mild, but in severe hepatitis (SH), it can be very serious and cause liver function failure, therefore, we should pay more attention to TTV when studying the possible pathogens of so-called "liver hepatitis of unknown etiology".