Immune-mediated hepatitis-associated aplastic anemia caused by the emergence of a mutant hepatitis B virus undetectable by standard assays

Hepatitis-associated aplastic anemia (HAA) is characterized by marrow failure developing after acute seronegative hepatitis. A patient with agammaglobulinemia developed HAA in association with HBsAg-negative, hepatitis B virus (HBV) DNA-positive acute hepatitis. Sequence analysis showed several substitutions in the major antigenic determinant of HBsAg, potentially affecting the detection by diagnostic immunoassays. Viral mutants may therefore be implicated as etiologic agents of HBsAg-negative HAA. HBV DNA determination may be necessary to exclude mutant HBV as a cause of HAA, particularly in categories at high risk of mutant selection such as agammaglobulinemic and transplanted patients.

Comparison of commercial and in-house Real-time PCR assays for quantification of Epstein-Barr virus (EBV) DNA in plasma

Background

Epstein-Barr virus (EBV) DNA load monitoring is known to be useful for the diagnosis and monitoring of EBV-associated diseases. The aim of this study is to compare the performance of two real-time PCR assays for EBV DNA: a commercial kit as the Q-EBV Real-Time System (Q-EBV PCR, Amplimedical, Turin, Italy) and an in-house assay (EBV RQ-PCR).

Results

The range of linearity and the degree of precision of the two assays were similar. The clinical sensitivity of Q-EBV PCR was higher for reference samples containing less than 1,000 EBV DNA copies/ml. The absolute quantitative results of the two methods were statistically correlated (R² = 0.7789; p < 0.0001), with the systematic overestimation by EBV RQ-PCR possibly linked to different amplification efficiency in calibration standards.

Conclusion

Both the commercial and the in-house assay may be appropriate for clinical use, but common standards are advisable for comparable absolute values, as these would improve the clinical utility of EBV DNA load measurement.

The Impairment of CD8 Responses Limits the Selection of Escape Mutations in Acute Hepatitis C Virus Infection

Evasion from protective CD8 responses by mutations within immunodominant epitopes represents a potential strategy of HCV persistence. To investigate the pathogenetic relevance of this mechanism, a careful search for immunodominant CD8 epitopes was conducted in six patients with chronic evolution of HCV infection by analyzing their global CD8 response with a panel of overlapping synthetic peptides covering the overall HCV sequence and by studying the CD8 frequency by tetramer staining. Immunodominant responses were followed longitudinally from the time of acute onset in relation to the evolution of the epitopic sequences. Although intensity of CD8 responses and frequency of HCV-specific CD8 cells declined over time in all patients, mutations emerged in only three of the six acute patients studied. Variant sequences were less efficiently recognized by CD8 cells than parental epitopes and were poorly efficient in inducing a CD8 response in vitro. CD8 epitopes undergoing mutations were targeted by high avidity CD8 cells more efficient in effector function. Our data support the view that immunodominant CD8 responses are affected by inhibitory mechanisms operating early after infection and that the emergence of escape mutations represents an additional mechanism of virus evasion from those CD8 responses that are functionally preserved.

Association between heterozygosity for HFE gene mutations and hepatitis viruses in hepatocellular carcinoma

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are strong and independent risk factors for hepatocellular carcinoma (HCC) development. Patients with hereditary hemochromatosis (HH) are considered at risk of developing cancer. However, the interaction between HFE gene mutations and hepatitis viruses for HCC development has not been systematically searched for. To assess the interaction between HFE gene mutations and exogenous risk factors in the risk of HCC occurrence, a case-only approach, in which just a series of patients is enrolled, was used. Three hundred three cirrhotic patients (231 males, 72 females) from five liver units in different geographic areas of Italy, who developed HCC during regular follow-up between January 1999 and March 2003, and whose blood DNA was available, were analyzed. In all subjects, hepatitis B surface antigen (HBsAg), anti-HCV and HFE gene mutations were assayed; alcohol intake was recorded by history. The interaction between HFE genotypes and hepatitis viruses for HCC was estimated by multivariate analysis adjusting for the confounding effect of alcohol intake, area of residence and months of follow-up. Of the 303 HCC cases, 12 (4.0%) were heterozygous for the C282Y mutation, 93 (30.7%) for the H63D, and 198 (65.3%) homozygous for the wild allele. Multivariate analysis showed that C282Y heterozygous males were 3.8-fold (95% CI=1.0-15.2) more likely to be HBV positive and that H63D heterozygous females were 6.0-fold (95% CI=1.2-113.8) more likely to be HCV positive than wild type subjects. In conclusion, given the association between C282Y mutation and HBV infection in male patients with HCC, a careful evaluation and follow-up should be considered in the C282Y-positive subjects with hepatitis B virus related liver disease. The interaction between the H63D mutation and HCV, observed only in women, may reflect a higher sensitivity to H63D-induced iron metabolism abnormalities and a reduced antioxidant capability in the presence of an even minor increase of iron which may occur as a consequence of the coexistence of hepatitis C infection and heterozygosity for HH.

Frequency of hepatitis B virus mutant in asymptomatic hepatitis B virus carriers receiving prophylactic lamivudine during chemotherapy for hematologic malignancies

Hepatitis B virus (HBV) reactivation is a potentially fatal complication of chemotherapy in asymptomatic HBV carriers. Prophylactic lamivudine has proven effective for its prevention, but the potential emergence of lamivudine-resistant HBV YMMD mutants, as shown in patients treated for chronic hepatitis, may limit its use. To evaluate the frequency of HBV YMMD mutant and its clinical significance, we have analysed 32 courses of primary lamivudine prophylaxis given to HBV carriers with haematologic malignancies, from the start until 1-5 months after the end of chemotherapy. Lamivudine was used for a median of 6 months (range 2-24+) and median follow-up was 19.5 months (range 5-40). Four episodes of HBV reactivation with mild hepatitis and no evidence of mutant strain occurred after chemotherapy completion and after lamivudine withdrawal. At follow-up YMMD mutant was detected in one patient with normal transaminase levels, who had been on continuous lamivudine for 20 months. In conclusion, among HBV carriers treated with chemotherapy for haematologic malignancies, the emergence of HBV YMMD mutant occurred in 3.1% of prophylactic lamivudine courses and was of little clinical relevance.

Role of viral and host factors in HCV persistence: which lesson for therapeutic and preventive strategies?

Several lines of evidence support the view that hepatitis C virus is not directly cytopathic for infected host cells and that the immune response plays a central role in the pathogenesis of liver damage. Innate and adaptive immune responses are induced in most individuals infected with hepatitis C virus but are insufficient to eliminate the virus. The mechanisms responsible for this failure are largely unknown but the kinetics of hepatitis C virus replication relative to the priming of the adaptive responses may exert a profound influence on the balance between virus and host. Immediately after hepatitis C virus infection, the virus replicates efficiently, inducing the production of type I interferons. However, the rapid increase in viral replication seems to be ignored by the adaptive immune response, and after a short interval from exposure, viral load can reach levels comparable to those of patients with established persistent infection. The CD8-mediated response shows functional defects, with impaired production of interferon-gamma, low perforin content, decreased capacity of expansion and lysis of target cells. Late appearance and functional defects of T cells in hepatitis C virus infection might be the result of the rapid increase of the viral load that could create the conditions for exhaustion of the adaptive response or reflect an insufficient function of the innate immune response. This possibility is suggested by in vitro studies showing that hepatitis C virus gene products can interfere with the anti-viral activity of type I interferons and natural killer cells as well as with the maturation of dendritic cells. While T-cell defects are reversed in a minority of infected individuals who succeed in controlling the infection, the T-cell impairment becomes progressively more profound as infection progresses to chronicity. In this situation, therapeutic restoration of adaptive responses may represent a rational strategy to obtain resolution of infection and to complement available therapies. The peculiar kinetics of hepatitis C virus replication and T-cell induction soon after infection may have important implications also for the design of protective vaccines since memory responses may not be able to precede the early peak of viral replication. Therefore, vaccines against hepatitis C virus may be unable to prevent infection but may rather be effective in facilitating a self-limited evolution of infection.

Prolonged treatment with imatinib mesylate in patients with advanced chronic myeloid leukemia causes a reduction of bcr/abl mRNA levels independent of cytogenetic response

Bcr/abl mRNA levels were monitored in 13 patients with chronic myeloid leukemia receiving imatinib mesylate over a period of 78 weeks. During treatment median bcr/abl mRNA levels progressively declined from 77.2 normalized dose (nD) at baseline to 11.28 nD after 13 weeks ( P<0.05) and to 1.28 nD after 78 weeks ( P<0.05). After 13 weeks, bcr/abl mRNA levels were significantly lower in cytogenetic responders compared to nonresponders ( P<0.05), but subsequent decrease in the transcript levels caused the loss of any correlation to the cytogenetic status. These results suggest that bcr/abl mRNA levels may reflect cytogenetic response only during the early phases of imatinib therapy.

Real-time quantitation of hepatitis B virus (HBV) DNA in tumorous and surrounding tissue from patients with hepatocellular carcinoma

Few data are available on the levels of HBV DNA in liver tissue of patients with hepatocellular carcinoma. In this study, HBV DNA was quantitated by a TaqMan real-time PCR method and results were normalised to an endogenous reference gene. The assay could detect reproducibly viral sequences from over 10(7) to less than 50 copies/microg of liver DNA. The HBV DNA content in liver samples from 11 HBsAg-positive patients (median: 10(5) copies/microg of DNA) was significantly higher (P < 0.001) compared to the viral DNA concentration detected in liver samples from 15 of 25 HBsAg-negative patients (median: 2.6 x 10(2) copies/microg). A liver DNA amount > or =1 HBV DNA copy per cell was detected in half of tissue samples from HBsAg-positive patients, and in none from HBsAg-negative ones. Liver tissue HBV DNA content was significantly higher in anti-HCV-negative than in anti-HCV-positive cases (P < 0.001). These results show that the quantitation of liver HBV DNA by real-time PCR can be useful to understand HBV state in hepatocellular carcinoma and viral interplay in patients with multiple viral infections.

Prevalence and genomic variability of transfusion transmitted virus in Italian cryptogenic chronic liver disease and healthy blood donors

BACKGROUND

Infection with transfusion transmitted virus, a new member of the Parvoviridae family, has been found in patients both with chronic and fulminant post-transfusion cryptogenic hepatitis.

AIM

To evaluate the prevalence and clinical impact of transfusion transmitted virus infection in Italy.

PATIENTS AND METHODS

Studies were carried out on 256 patients and control subjects from three centres from Northern, Central and Southern Italy (92 nonA-nonC chronic hepatitis, 10 acute non fulminant cryptogenic hepatitis, 41 hepatitis C virus-related chronic hepatitis and 113 blood donors). Serum transfusion transmitted virus was detected by nested polymerase chain reaction using two overlapping sets of primers.

RESULTS

A total of 52 of the 92 patients (54.3%) with chronic cryptogenic liver disease and 17 of the 41 hepatitis C virus chronic hepatitis patients (41.4%) were transfusion transmitted virus-DNA positive. Transfusion transmitted virus co-infection in hepatitis C virus patients was not associated with either a higher severity of liver histology or higher alanine transaminase levels or signs of cholestasis, transfusion transmitted virus was found in 48 out of 113 (42.4%) blood donors. In the majority of samples, transfusion transmitted virus DNA was detected with only one of the two sets of primers used. Genotyping and phylogenetic analysis performed on 21 randomly selected viral isolates showed the presence of both type 1 and type 2 transfusion transmitted virus and allowed identification of two isolates with high homology to genotype 6, described, so far, mostly in Japan.

CONCLUSIONS

Transfusion transmitted virus type 1 and 2 infection is common among blood donors and patients with liver disease in Italy. The pathogenic potential of transfusion transmitted virus type 1 and 2 in nonA-nonC hepatitis patients is unlikely but further studies are needed to evaluate the epidemiological and clinical impact of other transfusion transmitted virus subtypes.

Transmission of SEN virus from mothers to their babies

Sera from 30 women at high risk for infection, one half of which were SEN virus positive (SENV(+)), were collected at delivery to study SENV mother-to child transmission. Thirteen of their babies were positive for at least one SENV strain: one baby was SENV(+) at birth, eight became positive within 6 months from delivery, and four became positive in the following months. Our data indicate that vertical transmission of SENV does occur, presumably, at delivery, but it may not induce persistent viremia. This is supported by the fact that, generally, SENV is not detected at birth, by the high SENV homology in the sequences found in the mothers and in their children, by a lack of other risk factors for infection of the babies, and by the irregular detection of SENV in the follow-up. No clinical events surely linked to SENV infection were found, but transient elevations of alanine aminotransferase were observed in babies followed for a long period of time.

Quantitative analysis of hepatitis B virus DNA by real-lime amplification

Diagnostic assays allowing the quantification of hepatitis B virus (HBV) DNA over a wide range of concentrations are important for monitoring patients during antiviral therapy. The aim of this study was to develop a new real-time method for HBV DNA quantification. Primers and probe were selected in a highly conserved region of the HBV S gene, and a plasmid containing the pre-S/S region was used as a standard. Linear quantification of the standard was obtained between 10 and 10(9) copies/reaction, with high correlation between ayw and adw genomes (P<0.001). HBV DNA was detected in serial dilutions of a high-titer serum sample with linear results until 2.4 x 10(3) copies/ml. One hundred eight serum samples positive for hepatitis B surface antigen were tested in both the real-time assay and the Digene Hybrid Capture assay (Digene, USA). HBV DNA could be detected by both assays in 70 samples, with significant correlation of results (P<0.001). Results for 38 samples were below the sensitivity limit of the Digene assay, but they could be quantified by the real time polymerase chain reaction assay. These results show that real-time polymerase chain reaction allows sensitive, rapid and linear quantification of HBV DNA in serum.

Hepatitis C virus (HCV) RNA determination after two weeks of induction interferon treatment is an accurate predictor of nonresponse: comparison of two treatment schedules

The aim of this study was to analyze of HCV kinetics during interferon treatment administered daily or three times weekly. Seventy-seven naive patients were randomized to two treatment courses starting with four weeks of high-dose interferon administered daily or three times weekly. Twenty-two patients (28.6%) achieved end-of-treatment response and nine (11.7%, four of whom received daily induction) sustained response. The initial decline of viral load was sharper in patients receiving daily induction, but the rates of early RNA clearance were independent of treatment schedule, being higher in patients with genotype non-1. Detectable HCV RNA during treatment predicted nonresponse more significantly than high pretreatment viral load or genotype 1. HCV RNA at week 2 was the best predictor (100% sensitivity in patients receiving daily induction). In conclusion, daily induction increased the HCV decline slope, but not the rate of virological response. HCV RNA at week 2 reliably identified nonresponders.

Influence of maternal CD4 levels on the predictive value of virus load over mother-to-child transmission of human immunodeficiency virus type 1 (HIV-1). Study Group for Vertical Transmission

Forty-four anti-HIV seropositive pregnant women were enrolled in a study of maternal factors related to mother-to-infant human immunodeficiency virus type 1 (HIV-1) transmission. HIV-1 infection was documented in 11 of 45 infants (24.4%). Obstetric factors, maternal CD4 counts, and disease stage were not related to the risk of transmission. HIV-1 RNA levels at delivery were significantly higher in mothers who transmitted the infection (P = .024). A strong relationship between viral load and risk of transmission was observed in women with stage A1 (P= .006), but not in those with stages A2-A3. These results suggest that vertical transmission of HIV-1 is multifactorial and that viral load plays a major role in mothers with early-stage HIV-1 infection.

Prospective study of mother-to-infant transmission of hepatitis C virus (HCV) infection. Study Group for Vertical Transmission

Seventy-five women with anti-hepatitis C virus (HCV) antibody were enrolled prospectively during pregnancy or at delivery for study of mother-to-child transmission of HCV. Twenty-three women were coinfected with the human immunodeficiency virus (HIV). Seventy babies were monitored for at least 6 months. HCV infection was diagnosed in six infants (8.6%), four of whom were born to anti-HIV-positive mothers. HCV RNA was first detected between 2 and 6 months, and the genotypes of infected babies matched those of their mothers (type 1: n = 4; type 3: n = 2). Identical master sequences of the hypervariable region (HVR1) were detected in a mother-infant pair. In three babies coinfected with HCV and HIV, anti-HCV disappeared between 2 and 7 months, being persistently negative in two cases monitored for 11 and 26 months. Transmitting mothers did not differ significantly from those who did not transmit the infection with anti-HIV, HCV genotypes, and viral load at delivery, but had lower rate of reactivity to C100 by the recombinant immunoblot assay (RIBA) (P < .01). This prospective study confirms transmission of HCV from anti-HIV-negative mothers (4.4% in this series). Absence of anti-C100 antibodies at delivery is apparently related to increased risk of vertical transmission. Seronegative HCV infection can be observed in children coinfected with HIV.

Virological response to interferon treatment in hepatitis C virus carriers with normal aminotransferase levels and chronic hepatitis

Hepatitis C virus (HCV) carriers with normal aminotransferase levels often show histological chronic hepatitis. This study was undertaken to determine the effect of interferon (IFN) in such patients. Nineteen HCV carriers with normal aminotransferase activities and chronic hepatitis were randomized to receive IFN-alpha2b (3 million units 3 times weekly for 12 months) or no treatment. Therapy was monitored by qualitative and quantitative determination of viral RNA. Patients who did not clear HCV RNA after 6 months discontinued therapy. In all, 9 patients constituted the control group, while 10 patients were treated. Five of these patients, still viremic after 6 months, stopped IFN. The remaining 5 patients, who cleared the viral RNA within 6 months, completed the 12-month course. Three of these patients relapsed off treatment, and 2 were still free of viremia 12 months after stopping therapy. A transient flare-up of aminotransferase activities was detected in 2 patients during treatment and in 3 patients after. None of the 9 control patients cleared the viral RNA during follow-up. A variable degree of sequence heterogeneity was detected in the hypervariable region before therapy, and IFN treatment decreased sequence diversity in all patients. These results indicate that IFN therapy can be effective in chronic HCV carriers with normal aminotransferase activities, inducing short-term virological response in 3 of 10 patients and sustained response in 2. The effects of treatment on viral load and quasispecies complexity were similar to those reported previously in patients with increased aminotransferase activities.

Effects of interferon treatment on the antiviral T-cell response in hepatitis C virus genotype 1b- and genotype 2c-infected patients

The viral genotype may influence the response to interferon (IFN) treatment in chronic hepatitis C virus (HCV) infection. To characterize potential mechanisms responsible for this effect, we assessed whether IFN modulation of HCV-specific T-cell responses differs in patients infected by different genotypes. The T-cell response to HCV core protein was sequentially analyzed before and during IFN treatment in two groups of patients chronically infected with HCV genotype 1b (eight patients) or 2c (eight patients). Overlapping 20 mer peptides corresponding to the amino acid sequence of the prevalent viral population identified in the serum of each patient were used for the analysis of the T-cell proliferative response to avoid possible problems caused by amino acid differences between infecting virus and HCV proteins used in vitro. Recombinant HCV core antigen was used in parallel. The level of viremia was monitored by competitive polymerase chain reaction (PCR). The T-cell response to HCV peptides and recombinant core protein detected throughout the follow-up was significantly more vigorous in genotype 2c- than in genotype 1b-infected patients. This difference was the result of a greater enhancement of the T-cell response caused by IFN treatment in genotype 2c- compared with genotype 1b-infected patients. The different IFN modulatory effect on T cells from genotype 1b- and genotype 2c-infected patients illustrates an aspect of the virus-host interaction, which may contribute toward the explanation of why different genotypes differ in responsiveness to IFN treatment.

Outbreak of hepatitis C virus infection in patients with hematologic disorders treated with intravenous immunoglobulins: different prognosis according to the immune status

The influence of immunodeficiency on the course of hepatitis C virus (HCV) infection is still debated, although a worsening effect has been suggested. We compared the characteristics of hepatitis C in two groups of hematologic patients with different levels of immunocompetence who acquired the same virus strain after treatment with contaminated intravenous immunoglobulins (IVIG). Indications for IVIG therapy were idiopathic thrombocytopenic purpura (ITP) in six patients and hypogammaglobulinemia in 7 patients with various hematologic disorders, who were defined immunodeficient (ID). Infection rate was 100%. Five ID patients never developed HCV antibodies despite serum HCV-RNA positivity. The same HCV genotype was shown in 10 patients tested. Moreover, E1-E2 gene partial nucleotide sequencing, performed in four patients, showed identical or closely related amino acid sequences, thus strongly supporting the hypothesis of a common source of infection. Clinical acute infection did not differ significantly between the two groups, but subsequent liver failure developed in five of the seven ID patients and in none of the ITP patients (P = .04). Liver biopsy, performed in three cases, documented HCV as the only cause of liver damage. Six ID patients died, with liver disease being the primary cause of death in four cases and a contributory cause in two cases. Their median survival after IVIG was 12 months, significantly worse than that of ITP patients (P = .0028). We conclude that immunodeficiency markedly worsens the course of IVIG-acquired HCV infection in hematologic patients.