Stability of HCV-RNA level and its lack of correlation with disease severity in asymptomatic chronic hepatitis C virus carriers

This study examines the relationship between HCV-RNA levels and disease severity in 60 individuals with chronic hepatitis C virus infection. HCV-RNA levels were quantified by the branched DNA (bDNA) assay in 445 samples (median: eight samples per patient) obtained over a median of 40.4 months (95% confidence interval (CI): 37.0-42.5). The median log HCV-RNA level was 6.77 (95% CI: 6.62-6.92) molecular equivalents/mL (MEQ/mL). The median log range of HCV-RNA levels in individual patients over the course of the study was 0.89 (95% CI: 0.69-1.16). HCV-RNA level varied over time by less than one log in 62% of patients, by 1-1.5 logs in 22% and by greater than 1.5 logs in only 17%. Univariate analysis, revealed an inverse association between HCV-RNA levels and ALT levels (P=0.037). Univariate and logistic regression analysis showed no significant association between HCV-RNA levels and either the degree of inflammation or fibrosis. In contrast, there was a significant positive association between alanine aminotransferase (ALT) levels and histological activity especially in individuals with ALTs> 100 IU/L. Hence, HCV-RNA levels: (i) almost always fell within the dynamic range of the bDNA assay; (ii) were stable in asymptomatic chronically infected patients, with only a small proportion of patients exceeding a range of 1.5 logs; (iii) did not correlate with either the extent of inflammation or degree of fibrosis. In contrast, there was a strong association between ALT level and the histological severity of liver disease.

The outcome of acute hepatitis C predicted by the evolution of the viral quasispecies

The mechanisms by which hepatitis C virus (HCV) induces chronic infection in the vast majority of infected individuals are unknown. Sequences within the HCV E1 and E2 envelope genes were analyzed during the acute phase of hepatitis C in 12 patients with different clinical outcomes. Acute resolving hepatitis was associated with relative evolutionary stasis of the heterogeneous viral population (quasispecies), whereas progressing hepatitis correlated with genetic evolution of HCV. Consistent with the hypothesis of selective pressure by the host immune system, the sequence changes occurred almost exclusively within the hypervariable region 1 of the E2 gene and were temporally correlated with antibody seroconversion. These data indicate that the evolutionary dynamics of the HCV quasispecies during the acute phase of hepatitis C predict whether the infection will resolve or become chronic.

Analysis of hepatitis G virus (HGV) RNA, antibody to HGV envelope protein, and risk factors for blood donors coinfected with HGV and hepatitis C virus

Serologic, biochemical, and molecular analyses were used to study hepatitis G virus (HGV), antibody to the HGV envelope protein (anti-E2), risk factors, clinical significance, and the impact of HGV on coexistent hepatitis C virus (HCV). Among 329 donors with confirmed HCV infection, 12% were HGV RNA-positive and 44% were anti-E2-positive (total exposure, 56%). HGV RNA and anti-E2 were mutually exclusive except in 9 donors (1.5%); 8 of 9 subsequently lost HGV RNA but anti-E2 persisted. HGV had little impact on alanine aminotransferase, aspartate aminotransferase, or gamma-glutamyl transpeptidase in donors with HGV infection alone or those coinfected with HCV. A multivariate analysis showed that intravenous drug abuse was the leading risk factor for HGV transmission, followed by blood transfusion, snorting cocaine, imprisonment, and a history of sexually transmitted diseases. In summary, HGV and HCV infections were frequently associated and shared common parenteral risk factors; HGV did not appear to cause hepatitis or to worsen the course of coexistent hepatitis C.

Rapid and sensitive detection of cell-associated HIV-1 in latently infected cell lines and in patient cells using sodium-n-butyrate induction and RT-PCR

To develop a rapid and sensitive means of detecting cell-associated human immunodeficiency virus (HIV), donor cells from HIV seropositive patients were treated with the potent viral activator sodium-n-butyrate (NaB) and subsequently assayed by both in situ RNA hybridization and a reverse transcriptase polymerase chain reaction (RT-PCR). The sensitivity of RT-PCR was estimated to be equivalent to 1 x 10(-16) grams (0.1 fg) or approximately 64 copies of the input standard viral RNA per reaction. The present study takes advantage of the ability of NaB to introduce changes in chromatin structure of latently infected cells, leading to increased HIV gene expression. Human ACH-2 and U1 cell lines were used as representatives of T-lymphocytic and monocytoid cells harboring latent inducible proviruses. HIV gene expression was readily detected when these cells were treated with NaB. Viral gag RNA was detected by both in situ and RT-PCR assays. When peripheral blood mononuclear cells (PBMCs) from acquired immunodeficiency syndrome (AIDS) patients, who were all negative for in situ hybridization and serum/plasma p24 assays, were used for detection of viral gene expression, four categories with distinct patterns of induction were observed. The first set of patients showed HIV-positive PBMCs by RT-PCR without any added NaB, and suppression by added NaB or PHA. The second set of samples showed induction of viral RNA by NaB alone. The third set could be induced with PHA, but not NaB, and the fourth set required both NaB and PHA for induction of HIV gene expression. Our results suggest that direct treatment of the cells with HIV activators may be useful in increasing sensitivity of the RT-PCR intended to be used for detection of cell-associated viral RNAs. This approach may be used to confirm true status of the HIV infection when p24 results are negative or HIV RNAs in serum/plasma are below the threshold of detection. Moreover, this method may identify the presence of latent proviral genomes possibly reflecting the true rate of cell-associated viral load in vivo and without possible mutations brought about by long-term co-cultivation assays with cells from seronegative donors.

Detection of antibody to hepatitis C virus in prospectively followed transfusion recipients with acute and chronic non-A, non-B hepatitis

We measured antibody (anti-HCV) to hepatitis C virus, which causes non-A, non-B hepatitis, by radioimmunoassay in prospectively followed transfusion recipients and their donors. Of 15 patients with chronic non-A, non-B hepatitis documented by liver biopsy, all seroconverted for the antibody; of 5 with acute resolving non-A, non-B hepatitis, 3 (60 percent) seroconverted. The development of anti-HCV was delayed (mean delay, 21.9 weeks after transfusion, or 15 weeks after the onset of clinical hepatitis) and took approximately one year in one patient. Antibody has persisted in 14 of the 15 patients with chronic disease (mean follow-up, greater than or equal to 6.9 years; maximum, greater than or equal to 12), but has disappeared in the 3 with acute resolving disease after a mean of 4.1 years. Anti-HCV was detected in samples of donor serum given to 14 (88 percent) of the 16 anti-HCV-positive patients for whom all donor samples were available. Only 33 percent of the anti-HCV-positive donors tested had an elevated serum concentration of alanine aminotransferase; 54 percent were positive for antibody to the hepatitis B core antigen (anti-HBc). We conclude that hepatitis C virus is the predominant agent of transfusion-associated non-A, non-B hepatitis and that screening of donors for anti-HCV could prevent the majority of cases of the disease. "Surrogate" assays for anti-HBc and alanine aminotransferase would have detected approximately half the anti-HCV-positive donors involved in the transmission of hepatitis that we identified.

Antibody to hepatitis B core antigen as a paradoxical marker for non-A, non-B hepatitis agents in donated blood

The relationship between the presence of antibody to hepatitis B core antigen (anti-HBc) in donor blood and the development of hepatitis in recipients of that blood was studied in 6293 blood donors and 481 recipients who were followed for 6 to 9 months after transfusion. Of 193 recipients of at least 1 unit of blood positive for anti-HBc, 23 (11.9%) developed non-A, non-B hepatitis compared with 12 (4.2%) of 288 recipients of only anti-HBc-negative blood (p less than 0.001). Donor anti-HBc status was not significantly associated with the development of hepatitis B in the recipient and was negatively associated with the development of cytomegalovirus hepatitis. The relationship of donor anti-HBc status and the development of non-A, non-B hepatitis in the recipient was independent of transfusion volume and elevated donor transaminase level. Although 88% of anti-HBc-positive blood units were not associated with recipient non-A, non-B hepatitis, calculation of maximal corrected efficacy predicted that exclusion of anti-HBc-positive donors might have prevented 43% of the cases of non-A, non-B hepatitis with a donor loss of 4%. Because of the serious chronic consequences of non-A, non-B hepatitis, surrogate tests for non-A, non-B virus carriers must be seriously considered.