Balance module allows consistent monitoring and documentation of the pooling process for nucleic acid amplification technology testing

BACKGROUND AND AIMS

When performing minipool testing of blood donations for transfusion-transmissible viruses, it is crucial to correctly dispense plasma from each donation into the pools. However, concerns regarding the monitoring and documentation of the pooling process exist.

METHODS

A balance module with a tube holder has been developed, which can be easily integrated into liquid handling platforms. The existing software monitors and evaluates every single dispensing from primary samples to the minipool to confirm liquid arrival. The weighing accuracy of the balance module is approximately 2 mg per dispensing episode.

RESULTS

Ten thousand one hundred and fifty-six blood donations were tested on a Tecan Genesis RSP pipetting system. Thirty-one donations were not pipetted because the pipetting workstation identified a clot or sample shortage in the primary tube. The balance module exclusively detected another 18 mispipettings, which were outside of the acceptance criteria of 100 +/- 10%. The mean pipetted volume for these samples was 34.2 microl (range 0-87 microl). Visual inspection of the corresponding primary tubes showed blood clots, short sample or no apparent cause. The average deceleration of the pooling process, using the balance, was determined to be about 22%.

CONCLUSIONS

With the novel liquid arrival check system, complete and consistent process documentation of pooling for nucleic acid amplification technology (NAT) testing is feasible. It enables blood banks to monitor and compare every single dispense made with predefined, required volumes. Results can be transferred to the laboratory information management system for automated selective exclusion of inaccurately dispensed samples. ONE SENTENCE SUMMARY: Monitoring and documenting the pooling process for NAT testing using a balance-based liquid arrival check system.

Anti-HBc screening of blood donors: a comparison of nine anti-HBc tests

BACKGROUND AND OBJECTIVES

Since voluntary introduction of hepatitis B virus (HBV) minipool nucleic acid amplification technology (NAT) at the German Red Cross, the expected residual risk of a transfusion-associated HBV infection has been estimated to be 1 : 500,000 - about 10 times higher than for human immunodeficiency virus (HIV) or hepatitis C virus (HCV) infection. Donors demonstrating chronic positivity for antibody to hepatitis B core antigen (anti-HBc), negativity for hepatitis B surface antigen (HBsAg) and polymerase chain reaction (PCR)-negative with a low virus load are a major cause of this increased risk.

MATERIALS AND METHODS

Ten-thousand blood donors from our blood-donation centre were screened for anti-HBc using the current PRISM HBc and the new PRISM HBcore assay to evaluate the diagnostic sensitivity and specificity of these tests. PRISM HBc- or PRISM HBcore-reactive samples were further analysed using seven additional tests for anti-HBc, two tests for antibody to hepatitis B surface antigen (anti-HBs), one test for antibody to hepatitis B envelope antigen (anti-HBe) and three HBV NAT assays.

RESULTS

From a total of 10,000 donors, nine and 14 samples were reactive only in the PRISM HBc and the PRISM HBcore, respectively, whereas 165 samples were reactive in both anti-HBc assays. Further analysis of these 188 anti-HBc-reactive specimens in a total of nine different anti-HBc assays revealed concordant results for 162 (86.2%) specimens. Sample cut-off values for anti-HBc were significantly (P < 0.01) lower for anti-HBc-only reactive samples compared with specimens that were also reactive for anti-HBs or anti-HBe.

CONCLUSIONS

Both PRISM anti-HBc assays revealed that approximately 1.8% of non-prescreened blood donors from Germany were reactive for anti-HBc. Although sensitivity was comparable between both assays, specificity was increased significantly with the PRISM HBcore. High anti-HBc sample cut-off values were indicative for reactivity in other HBV parameters and for concordant results in the nine different anti-HBc assays. Look-back investigations are necessary to estimate the infection risk both of anti-HBc-only positive and of anti-HBc/anti-HBs-positive blood transfusions.

Fluorescence quencher improves scansystemtm for rapid bacterial detection

BACKGROUND AND OBJECTIVES

The optimized scansystem could detect contaminated platelet products within 24 h. However, the system's sensitivity was reduced by a high fluorescence background even in sterile samples, which led to the necessity of a well-trained staff for confirmation of microscope results.

MATERIALS AND METHODS

A new protocol of the optimized scansystem with the addition of a fluorescence quencher was evaluated. Pool platelet concentrates contaminated with five transfusion-relevant bacterial strains were tested in a blind study.

RESULTS

In conjunction with new analysis software, the new quenching dye was able to reduce significantly unspecific background fluorescence. Sensitivity was best for Bacillus cereus and Escherichia coli (3 CFU/ml).

DISCUSSION

The application of a fluorescence quencher enables automated discrimination of positive and negative test results in 60% of all analysed samples.

Molecular epidemiology of West Nile Virus in humans

After the introduction of West Nile Virus into the United States of America in 1999 followed by annual WNV epidemics during the mosquito seasons and spreading of the virus from the East (New York; 1999) to the West of the U.S. (California; 2003/2004) there appeared the question of whether a similar scenario could happen in Europe, too. To be able to answer this question the German Ministry of Health decided to investigate the prevalence and incidence of WNV infections in German blood donors. First a test algorithm was established taking into account the high level of cross-reactivity between different flavivirus infections in serological test systems. AntiWNV-suspicious specimens were further investigated for their neutralisation capacity and by an antiWNV confirmation assay developed in-house. As a preliminary result of our studies a very low prevalence of WNV infections in healthy German blood donors was measured. Development of highly specific test systems is necessary for accurate and reliable differential diagnosis of flavivirus infections.

Evaluation of an automated high-volume extraction method for viral nucleic acids in comparison to a manual procedure with preceding enrichment

BACKGROUND AND OBJECTIVES

Nucleic acid extraction still harbours the potential for improvements in automation and sensitivity of nucleic acid amplification technology (NAT) testing. This study evaluates the feasibility of a novel automated high-volume extraction protocol for NAT minipool testing in a blood bank setting.

MATERIALS AND METHODS

The chemagic Viral DNA/RNA Kit special for automated purification of viral nucleic acids from 9.6 ml of plasma by using the chemagic Magnetic Separation Module I was investigated. Analytical sensitivity for hepatitis C virus (HCV), human immunodeficiency virus-1 (HIV-1), hepatitis B virus (HBV), hepatitis A virus (HAV) and parvovirus B19 (B19) was compared to our present manual procedure that involves virus enrichment by centrifugation.

RESULTS

Chemagic technology allows automation of the viral DNA/RNA extraction process. Viral nucleic acids were bound directly to magnetic beads from 9.6-ml minipools. By combining the automated magnetic beads-based extraction technology with our in-house TaqMan polymerase chain reaction (PCR) assays, 95% detection limits were 280 IU/ml for HCV, 4955 IU/ml for HIV-1, 249 IU/ml for HBV, 462 IU/ml for HAV and 460 IU/ml for B19, calculated for an individual donation in a pool of 96 donors. The detection limits of our present method were 460 IU/ml for HCV, 879 IU/ml for HIV-1, 90 IU/ml for HBV, 203 IU/ml for HAV and 314 IU/ml for B19.

CONCLUSIONS

The 95% detection limits obtained by using the chemagic method were within the regulatory requirements for blood donor screening. The sensitivities detected for HCV, HBV, HAV and B19 were found to be in a range similar to that of the manual purification method. Sensitivity for HIV-1, however, was found to be inferior for the chemagic method in this study.

Dynamics of hepatitis C virus quasispecies turnover during interferon-alpha treatment

Interferon-alpha (IFN) has been shown to accelerate the evolution of hepatitis C virus (HCV) variants (quasispecies) in nonresponder patients. Different sensitivities of HCV variants to IFN are discussed as a possible mechanism. In the present study, quasispecies were investigated in detail by a newly established and validated direct solid-phase sequencing of the hypervariable region 1 (HVR1), during the initial 3 months of IFN therapy. According to single strand conformation polymorphism (SSCP) analysis, 14 of 26 (54%) virologic nonresponders with quasispecies evolution were identified. Six representative patients with SSCP changes were selected for frequent HVR1 sequencing. Pre-existing variants were identified by cloning and sequencing of the pretreatment serum HCV sample. In one patient the major type was substituted by a minor variant within 3 days of treatment while in the majority of patients the pretreatment major type did not decline before days 26-57 of treatment. Total serum HCV RNA levels remained constant in all patients. In conclusion, although quasispecies evolution during IFN therapy is common, it occurs after a wide range of time intervals after initiation of therapy. Thus, nonresponse to IFN cannot exclusively be explained by changes in the quasispecies.

TaqMan 5'-nuclease human immunodeficiency virus type 1 PCR assay with phage-packaged competitive internal control for high-throughput blood donor screening

Screening of blood donors for human immunodeficiency virus type 1 (HIV-1) infection by PCR permits the earlier diagnosis of HIV-1 infection compared with that by serologic assays. We have established a high-throughput reverse transcription (RT)-PCR assay based on 5'-nuclease PCR. By in-tube detection of HIV-1 RNA with a fluorogenic probe, the 5'-nuclease PCR technology (TaqMan PCR) eliminates the risk of carryover contamination, a major problem in PCR testing. We outline the development and evaluation of the PCR assay from a technical point of view. A one-step RT-PCR that targets the gag genes of all known HIV-1 group M isolates was developed. An internal control RNA detectable with a heterologous 5'-nuclease probe was derived from the viral target cDNA and was packaged into MS2 coliphages (Armored RNA). Because the RNA was protected against digestion with RNase, it could be spiked into patient plasma to control the complete sample preparation and amplification process. The assay detected 831 HIV-1 type B genome equivalents per ml of native plasma (95% confidence interval [CI], 759 to 936 HIV-1 B genome equivalents per ml) with a >or=95% probability of a positive result, as determined by probit regression analysis. A detection limit of 1,195 genome equivalents per ml of (individual) donor plasma (95% CI, 1,014 to 1,470 genome equivalents per ml of plasma pooled from individuals) was achieved when 96 samples were pooled and enriched by centrifugation. Up to 4,000 plasma samples per PCR run were tested in a 3-month trial period. Although data from the present pilot feasibility study will have to be complemented by a large clinical validation study, the assay is a promising approach to the high-throughput screening of blood donors and is the first noncommercial test for high-throughput screening for HIV-1.

Quasispecies heterogeneity of the carboxy-terminal part of the E2 gene including the PePHD and sensitivity of hepatitis C virus 1b isolates to antiviral therapy

Two regions within the HCV genome, hypervariable region 1 (HVR1) within the envelope (E)2 region and the PKR-binding domain (PKRbD) comprising the interferon sensitivity determining region (ISDR) within the nonstructural (NS)5A protein, have been reported to correlate with the outcome of antiviral treatment. Recently, a PKR/eIF2alpha phosphorylation homology domain (PePHD) within the E2 protein of HCV-1 isolates was described to inhibit PKR in vitro. PePHD deleted HCV-1 mutants remain capable of binding PKR to some extent while inhibition of PKR was found to be abolished by carboxy-terminal truncated E2 protein. The importance of mutations and quasispecies heterogeneity within the carboxy-terminal part of the E2 protein comprising the PePHD of HCV-1b is unknown. Therefore, the carboxy-terminal part of the HCV E2 gene (codons 618-746) including the PePHD was analyzed by sequencing of PCR products and individual clones of 41 HCV-1b-infected patients with sustained (SR, n = 12), end-of-treatment (ETR, n = 10), or no virological (NR, n = 19) response to antiviral therapy. Two highly conserved regions (codons 658-673 comprising the PePHD and codons 675-704) and one variable region (codons 705-720) were detected within the carboxy-terminal part of E2. No significant correlation of specific mutations or number of mutations with treatment response was observed for the PePHD and the carboxy-terminal part of the E2 protein. Phylogenetic and conformational analyses showed no specific clusters related to treatment outcome. Calculation of genetic complexity and diversity based on nucleotide sequence analyses of 20 individual clones per patient showed no differences between matched SR, ETR, and NR patients. However, calculation of genetic complexity and diversity on the basis of amino acid sequences showed significantly lower normalized Shannon entropy as well as mean Hamming distances for SR patients than in ETR and NR patients (P = 0.029 and P = 0.027, respectively). This indicates that patients achieving a sustained virological response to interferon-alpha-based antiviral therapy may elicit more effective immunological pressure, resulting in continuous clearing of individual variants of HCV quasispecies.

Yield and future issues of nucleic acid testing

Despite the much lower actual yield than that estimated for hepatitis C virus (HCV) and human immunodeficiency virus (HIV) nucleic acid testing (NAT)-only positives in the USA and Germany, look-back procedures have revealed that no HCV transmission has occurred in Germany since the introduction of NAT. This indicates sufficient sensitivity of the pool-PCR approach. The slow ramp-up of hepatitis B virus (HBV) however, may require a different approach. It has been shown in Germany that the pooling of samples followed by virus enrichment results in a significant yield. Single donation testing for HBV would not increase the yield, because virus enrichment from mini-pool results in a similar sensitivity to that of single donation testing. Both strategies may be useful for extending future NAT to HBV screening. New candidate viruses for NAT are Parvo B19 and hepatitis A virus (HAV) because of their extreme resistance to inactivation procedures. Their low pathogenicity and epidemiologic characteristics, however, make them candidate viruses only for pooled source plasma. The main future issues of NAT will be related to the automation of pooling, extraction and amplification as a single homogeneous process. Depending on the throughput, automated single donation NAT as demonstrated by the 'Tigris' system may be an option, as far as all transfusion-relevant viruses will be included. In the near future high throughput systems will rely on pooled donor samples, most probably in conjunction with efficient enrichment procedures. For these systems, automation of the extraction and amplification process will be one of the first steps. These procedures will also limitthe costs of NAT and keep it available for use with future candidate viruses.

Interferon alfa down-regulates CD81 in patients with chronic hepatitis C

CD81 protein has been shown to bind hepatitis C virus (HCV) envelope 2 (E2) glycoprotein in vitro and may act as a (co)receptor for HCV. Regulation of CD81 expression by interferon alfa (IFN-alpha) and ribavirin could thereby affect the response to antiviral therapy. In the present study, the effects of IFN-alpha and ribavirin on CD81 protein and CD81 mRNA were assessed in peripheral blood lymphocytes (PBL) and isolated human hepatocytes by fluorescence-activated cell sorter (FACS) analysis and real-time polymerase chain reaction (PCR), respectively. In addition, regulation of CD81 in PBL was investigated in 10 patients treated with combination therapy. Incubation with IFN-alpha (50 U/mL) down-regulated total CD81 in PBL (81.7 +/- 11.6% of control; P =.003) and in isolated human hepatocytes (91.6 +/- 8.1% of control; P =.034). Incubation with IFN-alpha with and without ribavirin (2.2 microg/mL) significantly reduced cell surface-associated CD81 protein (83.9 +/- 10.3% of control; P =.003). PBL of untreated patients chronically infected with HCV had significantly higher levels of total CD81 protein compared with PBL obtained from healthy donors (631.1 +/- 93.3 vs. 538.9 +/- 95.2 relative fluorescence units [RFU]; P =.030). Pretreatment cell surface-associated CD81 protein was lower in patients infected with genotype HCV-3 than those infected with HCV-1 (111.8 +/- 15.0 vs. 162.0 +/- 41.3 RFU; P =.019). Furthermore, cell surface-associated CD81 protein was lower 4 weeks after initiation of therapy in patients with an initial virologic response compared with initial virologic nonresponders (110.5 +/- 8.5 vs. 139.8 +/- 27.5 RFU; P =.057). In conclusion, IFN-alpha and ribavirin regulate CD81 expression in vitro and in vivo. CD81 expression correlates with HCV genotype and initial virologic response in patients with chronic hepatitis C.

Viral kinetics in patients with chronic hepatitis C treated with standard or peginterferon alpha2a

BACKGROUND & AIMS

Covalent attachment of a 40-kilodalton polyethylene glycol moiety to interferon alpha2a (peginterferon alpha2a) results in sustained delivery and reduced clearance compared with standard interferon alpha2a. The aim of the study was to compare viral kinetics in patients treated with standard or peginterferon alpha2a.

METHODS

Patients with chronic hepatitis C were randomly assigned to receive either standard interferon alpha2a thrice weekly (n = 16) or 180 microg peginterferon alpha2a once weekly (n = 17) for 48 weeks. HCV RNA was quantitated before and frequently during treatment.

RESULTS

The extent of the second-phase decline of HCV RNA, representing the degradation rate of infected cells during therapy for responding patients, was 0.02 +/- 0.03 day(-1) (HCV-1), 0.88 +/- 0.64 day(-1) (HCV non-1), 0.06 +/- 0.08 day(-1) (HCV-1), and 0.44 +/- 0.33 day(-1) (HCV non-1) in patients treated with standard or peginterferon alpha2a, respectively. The second-phase decline was low (<0.05 day(-1)) in most patients without a virological end-of-treatment response, and the second-phase decline was high (>0.25 day(-1)) in all patients with sustained virological response.

CONCLUSIONS

The degradation rate of infected cells is HCV genotype dependent. Treatment with peginterferon alpha2a may reinforce the death rate of infected cells (particularly in HCV-1-infected patients) or stabilize the therapeutic effect on viral production. The second-phase decline of HCV RNA is predictive of virological sustained response.

Comparative sequence analysis of the core- and NS5-region of hepatitis C virus from tumor and adjacent non-tumor tissue

The sequence variability within the core- and non-structural 5 (NS5)-region of the hepatitis C virus (HCV) was investigated in tumor and non-tumor tissue of 8 patients with HCV-associated hepatocellular carcinoma (HCC). Analyses of multiple clones containing polymerase chain reaction-amplified HCV sequences revealed a significantly higher variability within the core-region of tumor tissue isolates than of isolates from non-tumor tissue. Mutant sequence diversity ranged from silent mutations, as well as amino acid substitutions, appearance of in frame stop codons and deletions leading to frame-shifts. In contrast, the variability of the NS5-region sequences between isolates from tumor and non-tumor tissue was not significantly different. These observations might have important implications on the pathology of HCV, especially its potential tumorigenicity.

NAT and viral safety in blood transfusion

BACKGROUND AND OBJECTIVES

Nucleic acid testing was introduced at our blood transfusion service in order to reduce the diagnostic preseroconversion window for transfusion relevant viruses.

MATERIALS AND METHODS

Up to 96 donor samples were pooled overnight by two Tecan Genesis RSP 150 pipettors. Pools were centrifuged at 48,000 g for one hour to enrich viruses. Viral nucleic acids were extracted from centrifugation pellets using modified Qiagen viral RNA kit. HIV and HBV sequences were amplified by in house TaqMan PCR's with patented primers and probes for HBV. HCV PCR was performed by Roche Amplicor V2.0. "Nadis" software was developed for pooling, resolving positive pools and data communication with main frame computer.

RESULTS

PCR testing was introduced in January 1997 for HCV HBV and HIV-1 for all plasma products and for labile components at the 21st of April 1997. Throughput increased from 2000 to 4000 samples per day. PCR testing is done in parallel to serological testing and products are released eight hours after pooling is completed. Until January 2000, 1,078,940 donations have been tested in 13,274 pools. A total of seven PCR only positives were identified (3 HCV, 3 HBV, 1 HIV).

CONCLUSION

The yield of PCR testing for transfusion relevant viruses confirms theoretical estimates on the residual risk of antibody screening.

Prospective follow-up of patients with GBV-C/HGV infection: specific mutational patterns, clinical outcome, and genetic diversity

An association between a specific mutational pattern within the nonstructural (NS)3 region of GB virus-C/hepatitis G virus (GBV-C/HGV) genome and fulminant hepatic failure has been suggested recently. The mutational pattern consists of 3-6 nucleotide mutations of which one is leading to an amino acid exchange. In the present study, patients with GBV-C/HGV mono-infection (n = 24) or GBV-C/HGV and HCV co-infection (n = 20) were investigated prospectively. In 6/44 patients (14%) the mutational pattern within GBV-C/HGV NS3 previously associated with fulminant hepatic failure was identified by direct sequence analysis of the NS3 region. All 44 patients were asymptomatic clinically and had normal liver functions at initial presentation and after a median follow-up of 2.2 years. In 22/24 patients with GBV-C/HGV mono-infection and all patients with GBV-C/HGV and HCV co-infection GBV-C/HGV RNA remained detectable at the end of the study period, whereas two patients infected with GBV-C/HGV alone became negative for GBV-C/HGV RNA and developed GBV-C/HGV anti-E2 antibodies indicating recovery from GBV-C/HGV infection. Aminotransferase levels remained elevated or became normal independent of the persistence of serum GBV-C/HGV RNA. The median rate of nucleotide substitutions in GBV-C/HGV mono-infected and HCV co-infected patients was 3.4 x 10(-3) and 3.2 x 10(-3) per site per year, respectively. In conclusion, the prevalence of the mutational pattern within NS3 region of GBV-C/HGV associated previously with fulminant hepatic failure is about 14% and not associated specifically with severe liver disease. Over a median follow-up of 2.2 years less than 5% of patients cleared spontaneously GBV-C/HGV and no correlation between viraemia and elevated liver enzymes was observed.

Hepatocellular proliferation in patients with chronic hepatitis C and persistently normal or abnormal aminotransferase levels

BACKGROUND/AIMS

Some patients chronically infected with the hepatitis C virus (HCV) have persistently normal alanine aminotransferase (ALT) levels while progressive liver damage is observed histologically. In the present study, we compared the rate of proliferation, apoptosis, and necrosis in liver biopsy specimens of patients with persistently normal or elevated ALT levels.

METHODS

Fourteen patients with persistently normal and 14 age- and sex-matched patients with elevated ALT levels were enrolled. Proliferation was detected using anti-Ki 67 in 10-microm liver biopsy specimens of the patients. Apoptosis was measured by TUNEL-assay and by monoclonal anti-M30 directed against caspase-cleaved cytokeratin 18 filaments.

RESULTS

The mean number of anti-Ki 67 positive hepatocytes was lower in patients with persistently normal aminotransferases (3.1 +/- 2.8/10(3) vs 10.8 +/- 8.8/10(3) hepatocytes, p<0.0011) and was correlated with serum ALT (r=0.86, p<0.01) and aspartate aminotransferase levels (r=0.83, p<0.01). The rate of apoptosis detected by TUNEL assay was low and not different between patients with persistently normal and elevated aminotransferases. Staining with anti-M30 revealed a granular staining pattern and showed a trend towards higher cell death rates in patients with elevated aminotransferase levels (apoptotic hepatocytes with >75% staining: 3.97 +/- 6.24/10(3) hepatocytes vs 13.65 +/- 19.41/10(3) hepatocytes; p=0.08).

CONCLUSIONS

Patients with chronic hepatitis C and normal aminotransferases have significantly lower hepatocyte proliferation rates and show a trend towards lower apoptosis rates compared with patients with elevated aminotransferases.

Prospective follow-up of patients with GBV-C/HGV infection: specific mutational patterns, clinical outcome, and genetic diversity

An association between a specific mutational pattern within the nonstructural (NS)3 region of GB virus-C/hepatitis G virus (GBV-C/HGV) genome and fulminant hepatic failure has been suggested recently. The mutational pattern consists of 3-6 nucleotide mutations of which one is leading to an amino acid exchange. In the present study, patients with GBV-C/HGV mono-infection (n = 24) or GBV-C/HGV and HCV co-infection (n = 20) were investigated prospectively. In 6/44 patients (14%) the mutational pattern within GBV-C/HGV NS3 previously associated with fulminant hepatic failure was identified by direct sequence analysis of the NS3 region. All 44 patients were asymptomatic clinically and had normal liver functions at initial presentation and after a median follow-up of 2.2 years. In 22/24 patients with GBV-C/HGV mono-infection and all patients with GBV-C/HGV and HCV co-infection GBV-C/HGV RNA remained detectable at the end of the study period, whereas two patients infected with GBV-C/HGV alone became negative for GBV-C/HGV RNA and developed GBV-C/HGV anti-E2 antibodies indicating recovery from GBV-C/HGV infection. Aminotransferase levels remained elevated or became normal independent of the persistence of serum GBV-C/HGV RNA. The median rate of nucleotide substitutions in GBV-C/HGV mono-infected and HCV co-infected patients was 3.4 x 10(-3) and 3.2 x 10(-3) per site per year, respectively. In conclusion, the prevalence of the mutational pattern within NS3 region of GBV-C/HGV associated previously with fulminant hepatic failure is about 14% and not associated specifically with severe liver disease. Over a median follow-up of 2.2 years less than 5% of patients cleared spontaneously GBV-C/HGV and no correlation between viraemia and elevated liver enzymes was observed.

Detection of nucleic acid sequences from bacterial species with molecular genetic methods

While blood products become more safe in terms of viral contamination, the risk of transfusion-related bacterial infection has re-emerged to one of the major hazards in transfusion medicine. In recent prospective studies the rate of contaminated platelets ranged from 0.04 to 0.5%, and a rate of transfusion reactions between 0.007% and 0.046%. It is generally agreed that most of the organisms isolated from donated blood originate from the normal skin flora or from the environment. As it is unlikely that antiseptic methods can achieve absolute sterilization of the skin before venepuncture, blood banks have to rely on laboratory tests to detect contaminated blood products before release. But most of the currently available methods detecting bacterial contaminations do not have the potential to be sensitive and fast enough for a routine contamination screening in transfusion services. Here we present two alternative strategies based on molecular genetic techniques (Real-Time-PCR and Haystack processing) that detect or semi-quantify bacterial rRNA gene sequences for the majority of bacterial species. In addition we discuss some aspects on target selection, routine preparation and residual 16S-rDNA-contamination of enzymes.

Evaluation of a new PCR assay with competitive internal control sequence for blood donor screening

BACKGROUND

High-throughput nucleic acid testing for transfusion-relevant viruses by PCR requires contamination-proof methods with high sensitivity and validity. A new PCR reagent kit (TaqMan, PE BioSystems) reduces the risk of carry-over contamination by eliminating post-PCR processing.

STUDY DESIGN AND METHODS

Oligonucleotide design was done with software specialized for designing the assays' (TaqMan) primers and probes. A template-derived competitive internal control sequence designed through site-directed mutagenesis was used to reveal failures in amplification. Assay sensitivity was determined for single-donor and single-patient testing and by spiking sample mini-pools. Three seroconversion panels were tested.

RESULTS

Sensitivity is high, reaching 300 HBV genomes per mL of single-patient material on direct testing. A detection limit of 1000 HBV genome equivalents per mL of donor plasma is achieved for 96 pooled samples. The window period for HBV infection was reduced by 17, 10, and 63 days from that for HBsAg screening in three seroconverting donors.

CONCLUSION

The assay provides sufficient sensitivity to be superior to HBsAg screening in transfusion medicine and will be useful in clinical laboratories because of its ease of handling.

Mutations within the E2 and NS5A protein in patients infected with hepatitis C virus type 3a and correlation with treatment response

Defined regions of hepatitis C virus (HCV) envelope 2 (E2), PePHD, and nonstructural 5A (NS5A) protein (PKR-binding domain) have been shown to interact with interferon alfa (IFN-alpha)-inducible double-stranded RNA-activated protein kinase (PKR) in vitro, suggesting a possible mechanism of HCV to evade antiviral effects of IFN-alpha. The clinical correlation between amino acid mutations within the E2 PePHD or the NS5A PKR-binding domain and response to antiviral treatment in HCV-3a-infected patients is unknown. Thirty-three patients infected with HCV-3a isolates were treated with IFN-alpha with or without ribavirin. The carboxyterminal half of E2 and of the NS5A gene were sequenced. Sixteen patients achieved a sustained virological response (SR), 6 patients an end-of-treatment response with relapse thereafter (ETR), and 11 patients were nonresponders (NR). Within the PePHD of the E2 protein 0.5 (range, 0-2) mutations were observed in SR patients, whereas the number of mutations in ETR or NR patients was 0.2 (0-1). Quasispecies analyses showed almost no heterogeneity. The mean number of mutations within the PKR-binding domain of the NS5A protein was 1.6 (range, 0-4) in SR patients, 1 (0-2) in ETR patients, and 1.6 (0-3) in NR patients. Patients with higher numbers of mutations within the E2 or NS5A region showed a trend towards lower pretreatment viremia. Phylogenetic and conformational analyses of E2 or NS5A sequences allowed no differentiation between sensitive and resistant isolates. However, mutations within the E2 PePHD in SR patients were frequent, and hydrophobic mutations within the hydrophilic area of PePHD at codon 668 and 669 were exclusively observed in sustained virological responders.

Antiviral effect of human recombinant interleukin-12 in patients infected with hepatitis C virus

The heterogeneity of hepatitis C virus (HCV) is due to the continuous and high replication rate, the low fidelity of the RNA-dependent RNA polymerase, and the immune surveillance of the host. Interleukin-12 (IL-12) plays a central role in mounting an effective cellular immune response directed towards elimination of intracellular pathogens. The effect of IL-12 on hepatitis C viremia and the HCV quasispecies population is unknown. In this study, 12 patients (9 males, 3 females; mean age: 44 +/- 11 years), all virological non-responders to previous IFN-alpha treatment, received recombinant human IL-12 s.c. once weekly for 10 weeks stratified to three dose schedules (0.03 microg/kg, 0.1 microg/kg, and 0.5 microg/kg body weight, respectively). Fourteen IFN-alpha non-responders and 14 untreated patients served as age- and sex-matched controls. Serum HCV RNA concentrations and HCV quasispecies distribution were measured serially by quantitative reverse transcription - polymerase chain reaction and single strand conformation polymorphism analysis of the hypervariable region of the second envelope gene, respectively. Serum ALT and median HCV RNA levels before treatment (52.7 +/- 21.7 U/L; 2.6 x 10(6) copies/mL) showed no significant changes during IL-12 treatment (57.3 +/- 58.8 U/L and 3.2 x 10(6) copies/mL, 50.3 +/- 46.2 U/L and 3.1 x 10(6) copies/mL, and 46.8 +/- 35.3 U/L and 3.9 x 10(6) copies/mL at weeks 1, 4, and 10, respectively). Similar results were observed in 14 IFN-alpha non-responders and 14 untreated patients. However, changes in HCV quasispecies occurred in 10/12 (83%) and 9/14 (64%) patients treated with interleukin-12 and interferon-alpha, respectively, but only in 3/14 (21%) untreated subjects (P < 0.003 and P < 0.03). These results imply that interleukin-12 exerts only limited antiviral activity against certain HCV quasispecies in vivo.

Mutations in the protein kinase-binding domain of the NS5A protein in patients infected with hepatitis C virus type 1a are associated with treatment response

An interaction of the hepatitis C virus (HCV) NS5A protein with the interferon (IFN)-alpha-inducible double-stranded RNA-activated protein kinase (PKR) was demonstrated in vitro. The clinical correlation between amino acid mutations within the HCV NS5A region and response to antiviral treatment is controversial. Thirty-two patients chronically infected with HCV-1a, who were treated with IFN-alpha with or without ribavirin, were studied. The carboxy-terminal half of HCV NS5A was sequenced and was investigated by phylogenetic and conformational analyses. Eight patients achieved a sustained virologic response. An end-of-treatment response but relapse thereafter was observed among 8 patients, whereas 16 patients were nonresponders. The median number of mutations within the PKR-binding domain but not within the previously described IFN sensitivity-determining region was significantly higher for patients with sustained (3 mutations [range, 1-5]) or end-of-treatment (4 mutations [range, 1-5]) virologic response than for nonresponders (2 mutations [range, 0-3]) (P=.0087). Phylogenetic and conformational analyses of NS5A sequences allowed no differentiation between sensitive and resistant strains.

Enzymatic and antisense effects of a specific anti-Ki-ras ribozyme in vitro and in cell culture

Due to their mode of action, ribozymes show antisense effects in addition to their specific cleavage activity. In the present study we investigated whether a hammerhead ribozyme is capable of cleaving mutated Ki-ras mRNA in a pancreatic carcinoma cell line and whether antisense effects contribute to the activity of the ribozyme. A 2[prime]-O-allyl modified hammerhead ribozyme was designed to cleave specifically the mutated form of the Ki- ras mRNA (GUU motif in codon 12). The activity was monitored by RT-PCR on Ki- ras RNA expression by determination of the relative amount of wild type to mutant Ki-ras mRNA, by 5-bromo-2[prime]-deoxy-uridine incorporation on cell proliferation and by colony formation in soft agar on malignancy in the human pancreatic adenocarcinoma cell line CFPAC-1, which is heterozygous for the Ki-ras mutation. A catalytically inactive ribozyme was used as control to differentiate between antisense and cleavage activity and a ribozyme with random guide sequences as negative control. The catalytically active anti-Ki-ras ribozyme was at least 2-fold more potent in decreasing cellular Ki-ras mRNA levels, inhibiting cell proliferation and colony formation in soft agar than the catalytically inactive ribozyme. The catalytically active anti-Ki-ras ribozyme, but not the catalytically inactive or random ribozyme, increased the ratio of wild type to mutated Ki-ras mRNA in CFPAC-1 cells. In conclusion, both cleavage activity and antisense effects contribute to the activity of the catalytically active anti-Ki-ras hammerhead ribozyme. Specific ribozymes might be useful in the treatment of pancreatic carcinomas containing an oncogenic GTT mutation in codon 12 of the Ki-ras gene.

Improved correlation between multiple mutations within the NS5A region and virological response in European patients chronically infected with hepatitis C virus type 1b undergoing combination therapy

BACKGROUND/AIMS

Studies from Japan showed that HCV-1b isolates with at least four amino acid changes within NS5A2209-2248 compared with the prototype sequence HCV-J are more sensitive to interferon than isolates with a prototype sequence. However, the data were not unequivocally confirmed in studies from other geographical areas. These discrepancies may be explained by differences in the prevalence of multiple mutations within the NS5A2209-2248 and/or the treatment efficacy.

METHODS

In the present study, we therefore investigated the correlation between NS5A2209-2248 sequences of HCV-1b isolates and sustained virological response in 72 European patients treated with 3x6 MU interferon-a per week with (n = 26) and without (n = 46) ribavirin (1000-1200 mg/day). Serum HCV RNA was amplified by reverse transcription-polymerase chain reaction (RT-PCR) and the NS5A2209-2248 region was analyzed by sequencing of PCR products or individual clones.

RESULTS

Compared with HCV-1b prototype sequences, 19 patients (26%) had no amino acid changes (prototype), 47 patients (65%) had 1-3 mutations (intermediate type) and six patients (8%) had at least 4 mutations in the NS5A2209-2248 region (mutant type). Nine of the 12 patients with sustained virological response were infected with an intermediate type HCV-1b, the remaining three patients revealed a mutant type HCV-1b. A sustained virological response was achieved in three of four patients with a mutant type HCV-1b treated with interferon-alpha and ribavirin, but in none of the mutant type HCV-1b infected patients treated with interferon-a alone. Quasispecies analysis of HCV in the NS5A2209-2248 region showed only minor heterogeneity of the amino acid sequence.

CONCLUSIONS

The prevalence of mutant type HCV-1b isolates in European patients is low. In patients treated with combination therapy interferon-a and ribavirin, a correlation between mutant type HCV-1b isolates and sustained virological response was observed. The discrepancies between previous studies appear to be related to the efficacy of antiviral treatment and to the low prevalence of mutant type HCV-1b isolates in Western countries.

Feasibility and efficacy of routine PCR screening of blood donations for hepatitis C virus, hepatitis B virus, and HIV-1 in a blood-bank setting

BACKGROUND

Despite sensitive antibody-based blood-donor screening, a residual risk of transfusion-transmitted viral infections exists. Only direct monitoring by sensitive nucleic-acid tests would provide data accurately to measure the risk and to assess risk-reduction procedures. We investigated the feasibility and efficacy of routine screening of donors for hepatitis C virus (HCV), hepatitis B virus (HBV), and HIV-1 by PCR.

METHODS

For PCR testing, individual donor plasma samples were pooled (96x100 microL) overnight by two automatic pipetting machines. Viruses were concentrated by centrifugation and nucleic acids were extracted. HCV PCR was done on the Cobas Amplicor system (Hoffmann-La Roche, Mannheim, Germany). HBV and HIV-1 sequences were amplified by single (non-nested) in-house PCRs and detected by agarose-gel electrophoresis. Detection limits were 1000-5000 genome equivalents/mL in the donor blood.

FINDINGS

PCR testing was done in parallel to antibody screening with a maximum throughput of 3000 samples in 7-8 h. Positive samples were identified 1-2 days later. 111 of 373,423 donations (107 of 4500 pools) were PCR and antibody/antigen-confirmed positive. We found one HCV PCR-positive antibody-negative donation with normal alanine aminotransferase and one HCV PCR-positive donation with an elevated alanine aminotransferase (100 IU), which was negative in the AxSYM 2.0 and Matrix 1.0, but positive after control in the Abbott Prism test (Abbott GmbH, Wiesbaden, Germany).

INTERPRETATION

PCR is a suitable and fast blood-donor screening procedure and contributes to a reduction in viral transmission by transfusion of blood components. In our selected donor population, the yield of detected contaminated donations from donors in the time window in which they are highly infectious but do not have any symptoms or detectable antigen and antibody concentrations (diagnostic window), confirms theoretical estimates.

Peutz-Jeghers syndrome: molecular analysis of a three-generation kindred with a novel defect in the serine threonine kinase gene STK11

The Peutz-Jeghers syndrome, phenotypically characterized by mucocutaneous pigmentation and hamartomatous polyposis, is an autosomal dominant disease with variable expression and incomplete penetrance. Moreover, affected patients are at increased risk for gastrointestinal and other malignancies. Recently, a mutated gene encoding abnormal forms of the novel serine threonine kinase STK11 has been identified as a genetic cause of Peutz-Jeghers syndrome. Here, we report the molecular analysis of the STK11 gene in a patient with Peutz-Jeghers syndrome, which in exon 1 revealed a guanine (G) insertion in the 5 G repeat of codons 51-53. The insertion leads to a frameshift with a premature TGA stop codon 324 bp downstream in codon 162, predicting the expression of a truncated protein without kinase activity. This heterozygous germline mutation was also found in the affected father and in one affected sister of the index patient, but not in any phenotypically unaffected family member or in unrelated control subjects. In DNA isolated from microdissected hamartomatous polyps of the index patient, exon 1 of the STK11 gene could not be amplified suggesting that both alleles of STK11 exon 1 were lost in the hamartomatous polyps. Identification of a STK11 gene mutation in an index patient offers the possibility of a predictive diagnosis, and initiation of specific screening programs in the genetically affected kindred.

[GB virus-C/hepatitis G virus--discovery, epidemiology, diagnosis and clinical relevance]

Recently, two isolates of a new virus, designated GB virus C (GBV-C) and hepatitis G virus (HGV) were identified. Genomic organization place them in the family Flaviviridae, which includes HCV. A classification of GBV-C/HGV strains into at least three genotypes (West Africa, Europe/North America, Asia) has been proposed. GBV-C/HGV has a positive-stranded, linear RNA genome possessing a large open reading frame that encodes a single large polyprotein. As a possible genomic defect no core protein has yet been identified in GBV-C/HGV isolates. Whether GBV-C/HGV can be classified as a hepatotropic virus with replication in the liver is under discussion. The prevalence in the general population is high (2%). GBV-C/HGV is transmitted parenterally e.g., by transfusion of blood and blood products. Furthermore, cases of vertical and horizontal transmission are reported. Detection of GBV-C/HGV infection is exclusively possible by reverse transcription polymerase chain reaction (RT PCR). E2-specific antibodies are associated with loss of detectable GBV-C/HGV RNA and appear to indicate recovery from GBV-C/HGV infection. An acute icteric state with transient elevation of aminotransferases in association with GBV-C/HGV infection may exist. These cases are rare and approximately only 0.3% of persons with acute viral hepatitis are infected with GBV-C/HGV alone. Whether GBV-C/HGV is a cause of fulminant hepatic failure has not yet been proven. Persistent viremia of the GBV-C/HGV infection is frequent but is not related to chronic liver disease. Since no other chronic diseases associated with GBV-C/HGV infection could yet be identified, chronic GBV-C/HGV infections appear to be without clinical significance. GBV-C/HGV and hepatitis B or C virus (HBV, HCV) coinfection seem not to interfere with the outcome of HBV-respective HCV-related liver disease. The cause of the majority of cases with non-A-E viral hepatitis remains unknown and other yet undiscovered hepatic viruses must exist.

Effect of ribavirin on virus load and quasispecies distribution in patients infected with hepatitis C virus

BACKGROUND/AIMS

The combination of ribavirin and interferon alfa has potent synergistic effects in the treatment of chronic hepatitis C. The antiviral mechanism of ribavirin is unknown. We investigated whether a transient initial antiviral effect of ribavirin was sufficient to improve the response to interferon.

METHODS

Fifteen HCV-infected patients (ten male, five female; mean age 45.4+/-11.0 years) treated with ribavirin (1000-1200 mg) and 17 untreated patients with chronic hepatitis C (11 male, six female; mean age 45.6+/-9.9 years) were investigated. All patients were either non-responders to (n=19) or relapsed after (n=13) previous interferon treatment. Serum HCV-RNA concentrations and HCV quasispecies distribution were serially measured over 4 weeks by quantitative reverse transcription-polymerase chain reaction and single-strand conformation polymorphism analysis, respectively.

RESULTS

In six of the 15 patients treated with ribavirin, but in none of the controls, serum alanine aminotransferase levels declined by at least 30%. Pretreatment HCV-RNA levels ranged from 5.0x10(5)-5.0x10(7) copies/ml. After initiation of ribavirin treatment, minor (0.5-1.0 log) or no changes (<0.5 log) in total hepatitis C viremia were observed in ten and five patients, respectively. In HCV-infected patients without treatment 7/17 patients had minor and 10/17 no changes in viremia. Polymerase chain reaction amplification of the hypervariable region-1 of HCV was successful in 13/15 treated and in 17/17 untreated patients. Changes in HCV quasispecies according to the single-strand conformation polymorphism band pattern occurred in only one patient treated with ribavirin and in three of the untreated patients.

CONCLUSIONS

Ribavirin monotherapy has no initial antiviral effect on total hepatitis C viremia nor on HCV quasispecies. Unlike the rapid emergence of antiviral drug-resistant strains in HIV-infected patients, no viral escape phenomena are observed in HCV-infected patients treated with ribavirin.

Clinical evaluation of autoantibodies to p53 protein in patients with chronic liver disease and hepatocellular carcinoma

In hepatocellular carcinoma (HCC) of patients from the Western hemisphere, mutations in the p53 tumour suppressor gene are present in up to 37% of cases. Conformational change and cellular accumulation can initiate an immune response with generation of circulating autoantibodies to p53 protein. In the present study, we investigated 711 consecutive patients with chronic liver disease to evaluate the sensitivity and specificity of autoantibodies to p53 protein as a serological marker for HCC. Detection of p53 autoantibodies was performed using an enzyme-linked immunosorbent assay with immobilised recombinant p53 protein. Liver cirrhosis was present in 259 patients (36.4%) and a HCC was diagnosed in 75 patients (10.6%). Autoantibodies to p53 protein were detectable in 15 of 377 patients with chronic liver disease (4.0%) and in 10 of 259 patients presenting with liver cirrhosis (3.9%). All 25 p53 autoantibody-positive/HCC-negative patients were carefully investigated and no underlying malignancy was clinically detected, suggesting that elevated p53 antibody levels may not exclusively be detectable in patients with malignant disease. In patients with clinically manifest HCC, p53 autoantibodies were detected in 17 of 75 cases, thus resulting in a sensitivity of 22.7% and a specificity of 96.1%. In contrast, assessment of serum alpha-fetoprotein (AFP) resulted in a sensitivity and specificity of 69.3 and 91.8% (AFP > 20 ng/ml) and 53.3 and 99.1% (AFP > 100 ng/ml) for the detection of HCC, respectively. The data of the present study reveal that the presence of p53 autoantibodies in patients with chronic liver disease is not completely specific for HCC. Moreover, we obtained no direct evidence that p53 autoantibody formation precedes the clinical diagnosis of HCC. However, serological screening for HCC might be improved by combining AFP and p53 autoantibody assays.

Hepatitis C virus dynamics in vivo: effect of ribavirin and interferon alfa on viral turnover

Treatment of patients with chronic hepatitis C with recombinant interferon alfa (rIFN-alpha) can cause a decrease of serum transaminases and hepatitis C virus (HCV) RNA. Recent trials evaluating combination therapy of IFN-alpha and ribavirin suggested a potential synergistic effect. From serial measurements of serum HCV RNA concentrations following treatment-induced perturbation of the balance between virus production and clearance, we compared the antiviral efficacy of both IFN-alpha alone and IFN-alpha in combination with ribavirin. Chronically HCV-infected patients were treated with either 3 x 3 MU or 3 x 6 MU rIFN-alpha per week or 3 x 6 MU rIFN-alpha plus 14 mg/kg of body weight ribavirin per day. The time-dependent HCV RNA concentrations during antiviral treatment were analyzed by iterative least-squares regression. After initiation of antiviral therapy, HCV RNA declined exponentially below the detection limit of the reverse-transcription polymerase chain reaction assay (1,000 HCV RNA molecules per milliliter) in 10 of 26 (39%), 10 of 19 (53%), and 10 of 18 patients (56%) treated with 3 x 3 MU, 3 x 6 MU rIFN-alpha without and with ribavirin, respectively. Viral clearance from serum was faster in patients treated with 3 x 6 MU rIFN-alpha (t1/2 = 0.23 +/- 0.15) compared with patients treated with 3 x 3 MU rIFN-alpha per week (0.67 +/- 0.36 days) (P < .004). However, half-lives of viral clearance were similar in patients treated with rIFN-alpha or rIFN-alpha plus ribavirin. For virus release from infected hepatocytes, absence and presence of ribavirin yielded half-lives of t1/2 = 2.54 +/- 2.10 and t1/2 = 1.99 +/- 1.70, respectively, indicating that ribavirin does not significantly inhibit HCV production. In conclusion, the data of the present study indicate that higher rIFN-alpha doses accelerate viral clearance from serum. Ribavirin (14 mg/kg/d), however, lacks synergistic antiviral effects in the treatment of chronic hepatitis C with 3 x 6 MU rIFN-alpha per week.

Quantification of the initial decline of serum hepatitis C virus RNA and response to interferon alfa

Although several virus- and host-related predictive factors for the response to interferon alfa (IFN-alpha) have been defined in patients with chronic hepatitis C, no pretreatment parameter can definitely predict the response to antiviral treatment. Assessment of the initial response by quantification of serum hepatitis C virus RNA before and 4 weeks after initiation of therapy may be a clinically applicable and reliable parameter to predict long-term response. Therefore, the aims of the present study were to test the predictive value of a decline in HCV RNA of at least 3 log in the first 4 weeks of treatment (deltaHCV RNA) in patients treated with 3 x 10(6) units of recombinant IFN-alpha2a (rIFN-alpha2a) three times per week subcutaneously and to compare deltaHCV RNA with other established predictive factors, such as HCV genotype and pretreatment viremia. Serum HCV RNA was measured by a validated quantitative reverse transcription-polymerase chain reaction (RT-PCR). Geno/subtyping of HCV was performed by direct sequencing of the nonstructural (NS) 5B region of PCR-amplified isolates and subsequent phylogenetic analysis. Stable HCV RNA levels (deltaHCV RNA < or = 1 log) within the first 4 weeks of IFN-alpha treatment were present in 42 of 70 patients. A decline in HCV RNA levels between 1 to 3 log and more than 3 log was observed in 9 (13%) and 19 patients (27%), respectively. In 21 of 70 patients (30%), HCV RNA was not detectable at the end of 12 months' treatment. Three of 26 patients (11%) with a pretreatment viremia of < or = 10(6) copies/mL (all HCV subtype 3a) and 6 of 44 patients (14%) with a pretreatment viremia of > 10(6) copies/mL (HCV subtypes 1b, 2a, 2c, 3a [two patients], and 4) achieved a virological sustained response to interferon-alpha2a treatment. All patients with a virological sustained response had an initial deltaHCV RNA of more than 3 log. In a stepwise discriminant-function analysis, the initial deltaHCV RNA was confirmed as the strongest predictor of virological sustained response (P < .0001). In conclusion, the data of the present study suggest that IFN-alpha treatment can be terminated after 4 weeks in patients with a decrease in HCV RNA levels of less than 3 log, when apparent HCV eradication is considered the therapeutic target. The predictive value of deltaHCV RNA clearly exceeds the significance of HCV genotype and pretreatment viremia as predictors of successful IFN-alpha treatment.

Non-isotopic detection of hepatitis C virus quasispecies by single strand conformation polymorphism

In patients infected with the hepatitis C virus (HCV), a heterogeneous population of viruses, so-called quasispecies exists in vivo. The hypervariable regions (HVR) within the second envelope gene (HCV-E2) show particularly highly intratypic variability and are considered to be the target of neutralizing antibodies. The aims of the study were to optimize a genotype-independent primer set for amplification of HVR-1 and to establish a sensitive SSCP analysis for rapid and non-isotopic detection of predominant serum HCV quasispecies. Using the optimized SSCP technique, changes of quasispecies composition were investigated in five chronically infected patients with HCV before and during interferon-alpha treatment. HCV genotyping was performed by sequence and phylogenetic analysis. In addition, serial viremia and serum alanine aminotransferase (ALT) levels were determined. The SSCP analysis was performed at two time points before and during interferon-alpha therapy, respectively. Four patients showed an alteration of the SSCP pattern during the first three months of interferon-alpha therapy, whereas in one patient the SSCP pattern changed before therapy and remained stable during treatment with interferon-alpha. The present approach for non-isotopic analysis of single strand conformation polymorphism provides a direct, rapid, and sensitive technique for detection of the heterogeneous population of HCV quasispecies of different genotypes. Using this test procedure, investigations of large cohorts of patients with chronic hepatitis C can be undertaken.

[Prevalence of hepatitis G virus genome in blood donors]

The relevance of the GB virus C/hepatitis G virus (GBV-C/HGV) in blood banking results from its high prevalence in blood donors and the fact that it is present at a very high percentage (18%) in polytransfused and hemophiliac patients. Since there is no assay available for serological testing, we developed a sensitive PCR utilizing newly designed NS3 primers to investigate the prevalence in blood donors in Hessia. Testing 1,143 accepted blood donors with alaninaminotransferase (ALT) concentrations < 45 U/l we found 15 (1.3%) positive for GBV-C/HGV RNA. From 507 donors settling in urban Frankfurt areas, 10 (2.0%) were positive. Of those donors settling in rural hessian areas only 5/635 (0.8%) tested positive. By testing 100 excluded donors with ALT values > 45 U/l, 3% turned out to be positive. In 4 out of 9 recipients of GBV-C/HGV-positive blood products we detected the donor viral RNA as proved by sequencing and phylogenetic analysis. The virus was transmitted to 3 recipients by erythrocytes and to 1 recipient by platelets. Testing family members of the GBV-C/HGV-positive blood donors we could not detect any intrafamilial transmission.

Quantification of hepatitis C virus RNA by RT-PCR in comparison to the branched DNA method

INTRODUCTION

Quantification of hepatitis C virus (HCV) serum viremia levels is an important measure to predict and monitor response to interferon-alpha therapy as well as to predict clinical outcome. We were interested to compare the most widely used HCV quantification methods, quantitative RT-PCR (qRT-PCR) and the branched DNA (bDNA) method, with respect to sensitivity and reliability.

RESULTS

In the present study, 101 serum samples from patients chronically infected with HCV were simultaneously quantified by an in-house reverse transcriptase (RT)-PCR assay and the branched DNA Quantiplex HCV RNA kit 1.0 and 2.0. The concentration of HCV RNA molecules/ml serum ranged from 1.5 x 10(4) to 1.0 x 10(8) as assessed by our quantitative (q)RT-PCR. Serum concentrations of HCV-genotype 1 were significantly higher when measured with bDNA 1.0 compared to bDNA 2.0 and qRT-PCR, whereas measurements by qRT-PCR and bDNA 2.0 were concordant. Measurements of genotypes 2 and 3 by bDNA 2.0 were significantly higher than by bDNA 1.0. Significantly lower measurements were obtained for genotype 3 by qRT-PCR in comparison to bDNA 2.0.

CONCLUSION

Despite subtype-specific differences, there is clinically sufficient agreement in measurements between qRT-PCR and bDNA of HCV RNA concentrations. However, with respect to the therapeutic monitoring of the individual patient, kits and methods should not be exchanged.

Non-isotopic detection of hepatitis C virus quasispecies by single strand conformation polymorphism

In patients infected with the hepatitis C virus (HCV), a heterogeneous population of viruses, so-called quasispecies exists in vivo. The hypervariable regions (HVR) within the second envelope gene (HCV-E2) show particularly highly intratypic variability and are considered to be the target of neutralizing antibodies. The aims of the study were to optimize a genotype-independent primer set for amplification of HVR-1 and to establish a sensitive SSCP analysis for rapid and non-isotopic detection of predominant serum HCV quasispecies. Using the optimized SSCP technique, changes of quasispecies composition were investigated in five chronically infected patients with HCV before and during interferon-alpha treatment. HCV genotyping was performed by sequence and phylogenetic analysis. In addition, serial viremia and serum alanine aminotransferase (ALT) levels were determined. The SSCP analysis was performed at two time points before and during interferon-alpha therapy, respectively. Four patients showed an alteration of the SSCP pattern during the first three months of interferon-alpha therapy, whereas in one patient the SSCP pattern changed before therapy and remained stable during treatment with interferon-alpha. The present approach for non-isotopic analysis of single strand conformation polymorphism provides a direct, rapid, and sensitive technique for detection of the heterogeneous population of HCV quasispecies of different genotypes. Using this test procedure, investigations of large cohorts of patients with chronic hepatitis C can be undertaken.

Heterosexual transmission of GB virus-C/hepatitis G virus infection

GB virus-C (GBV-C) and hepatitis G virus (HGV) are recently identified non-A-E hepatitis-associated viruses belonging to the family Flaviviridae. The prevalence of GBV-C/HGV in the general population is high (1.2-3.0%), but data on possible transmission routes are sparse. In this report GBV-C/HGV RNA was detected in a couple by reverse transcription polymerase chain reaction (RT-PCR) using primers deduced from non-structural regions. Neither partner was coinfected with hepatitis B (HBV), hepatitis C (HCV) or human immunodeficiency virus (HIV). The child of the couple tested repeatedly negative for GBV-C/HGV by RT-PCR. The couple had lived in a stable monogamous relationship for 10 years and had never used barrier contraception. Other than sexual risk, factors for transmission were carefully excluded. GBV-C/HGV isolates obtained from the couple were sequenced and phylogenetically analysed together with control GBV-C/HGV isolates. The evolutionary distance between the sequences obtained from the couple (1%) was smaller than between any other GBV-C/HGV sequence. Taken together, the clinical and molecular data provide strong evidence for heterosexual but not vertical transmission of GBV-C/HGV in non-coinfected individuals.

Dynamics of hepatitis B virus infection in vivo

BACKGROUND/AIMS

Information on the kinetics of the pretreatment steady-state of HBV can be obtained from serial measurements of serum hepatitis B virus (HBV) DNA concentrations following lamivudine ((-)enantiomer of 3'-thiacytidine)-induced perturbation of the balance between virus production and clearance.

METHODS

In a placebo-controlled, dose-ranging trial, lamivudine (5 to 600 mg per day) was administered for 4 weeks to 17 patients with chronic replicative hepatitis B. Serum HBV DNA levels were quantified by standard liquid hybridization techniques. The time-dependent concentrations of serum HBV DNA following lamivudine administration were subjected to iterative least-squares regression in order to obtain kinetic data on HBV life-time and viremia.

RESULTS

In patients with stable HBe-antigen positive chronic hepatitis B responding to lamivudine, HBV DNA declined exponentially with a half-life of approximately 2-3 days. The minimum virus production and clearance per day in patients with chronic hepatitis B was calculated to be 6.09 x 10(11) virions/day (range 0.26 to 21.06 x 10(11) virions/day). Compared to the HBeAg levels before treatment, relative amounts of HBeAg were 1.00 +/- 0.16 and 0.96 +/- 0.20 at days 22 and 28 of treatment, respectively. Four weeks after termination of lamivudine treatment, the relative amount of HBeAg was 1.04 +/- 0.19.

CONCLUSIONS

The half-life of HBV in chronically infected patients is longer and in vivo turnover rates are higher compared to recently published data on the human immunodeficiency virus type 1 and the hepatitis C virus. The constant expression of HBeAg observed in the present study during a 28-day lamivudine treatment period does not allow calculation of a definite decay rate for virus-producing cells. Our data, however, imply that the minimum half-life of infected cells may exceed 100 days.

Prevalence and clinical and histological manifestation of hepatitis G/GBV-C infections in patients with elevated aminotransferases of unknown etiology

BACKGROUND/AIMS

Hepatitis G virus (HGV) and hepatitis GB virus-C (GBV-C) are recently identified non-A-E hepatitis-associated viruses. The prevalence of HGV/GBV-C in the general population is high (1.0-1.7%), but data on the clinical and histological manifestations of the new viruses are sparse. In the present study we investigated the prevalence and clinical and histological manifestation of HGV/GBV-C infections in patients with elevated aminotransferase levels of unknown etiology.

METHODS

In 52 of 630 consecutive patients referred for evaluation of elevated aminotransferases the underlying liver disease remained unknown. Serum samples of these 52 patients with elevated aminotransferase levels of unknown etiology were tested for HGV/GBV-C RNA by reverse transcription-polymerase chain reaction (RT-PCR) using primers deduced from nonstructural regions. Cloned PCR products were sequenced and compared by phylogenetic analysis.

RESULTS

HGV/GBV-C RNA was consistently detected in 7 of the 52 patients (13%). Sequence and phylogenetic analysis revealed the presence of only one subtype, with nucleotide sequence homologies between 86 and 91%. All seven patients had persistent viremia for at least 9 months. In six patients liver function test results normalized, and alanine aminotransferase levels remained persistently elevated in only one patient. Four HGV/GBV-C positive and ten HGV/GBV-C negative patients consented to a liver biopsy, which revealed similar results with minimal to mild chronic hepatitis and mild portal fibrosis.

CONCLUSIONS

The prevalence of HGV/GBV-C infections in patients with elevated aminotransferases of unknown etiology is low. Since clinical, biochemical and histomorphologic features of patients with elevated aminotransferases of unknown etiology with and without HGV/GBV-C infection are indistinguishable, the role of HGV/GBV-C in the pathogenesis of chronic liver disease appears insignificant.

Enlargement of perihepatic lymph nodes in relation to liver histology and viremia in patients with chronic hepatitis C

Inflammatory processes in organs frequently lead to hyperplasia of regional lymph nodes. In the present study, we investigated whether lymph node enlargement within the hepatoduodenal ligament may reflect the inflammatory activity within the liver of patients chronically infected with the hepatitis C virus (HCV). In 114 patients with chronic hepatitis C and 49 healthy controls, the total lymph node volume within the hepatoduodenal ligament was prospectively investigated by ultrasound. In patients with chronic hepatitis C, a liver biopsy was taken at the same occasion, and specimens were semiquantitatively evaluated by the histological activity index (HAI). Hepatitis C viremia was assessed by quantitative reverse transcription-polymerase chain reaction (RT-PCR). Genotyping was performed by a reverse hybridization assay. In 104 of 114 patients (91.2%) and in 45 of 49 healthy controls (91.8%), adequate visualization of the region of the hepatoduodenal ligament was achieved by ultrasound. Lymph nodes were detected in all patients with chronic hepatitis C and in 33 of 45 controls. The mean perihepatic lymph node volume in healthy controls (2.2 +/- 1.8 mL) was lower than in HCV-infected patients with mild to moderate inflammatory activity, severe inflammatory activity, and patients with cirrhosis (5.8 +/- 2.2 mL, 18.1 +/- 10.4 mL, and 22.8 +/- 18.8 mL, respectively). In patients with HCV-RNA levels of less than 10(6) copies/mL, the total lymph node volume was 5.8 +/- 1.6 mL and was significantly increased in patients with higher viremia (20.3 +/- 13.8 mL; P < 10(-6)). No correlation was found between the total lymph node volume within the hepatoduodenal ligament, HCV genotypes, and liver function test results. In conclusion, enlargement of perihepatic lymph nodes in patients with chronic hepatitis C is predictive for the presence of severe inflammatory activity. The mechanism of portal lymphadenopathy in patients with chronic hepatitis is unknown but appears to be related to viral replication within the liver and the immune-mediated inflammatory response of the host.

Anti-p53 autoantibodies in hepatitis C virus-infected patients

Mutations in the p53 gene with generation of circulating autoantibodies to p53 protein (anti-p53) have been recently detected in a significant proportion of patients with different malignant diseases. Using ELISA methods we assessed alpha-fetoprotein (AFP) and anti-p53 as serological screening parameters for hepatocellular carcinoma (HCC) in 147 consecutive patients with hepatitis C virus-related chronic hepatitis. Liver cirrhosis was histologically diagnosed in 58 patients (39,5%) and a HCC confirmed in 7 patients (4.8%). Serum AFP levels were raised above 20 ng/ml in 26/147 patients (17.7%) and above 100 ng/ml in 5/147 patients (3.4%). In 6/7 patients with HCC serum AFP was raised above 20 ng/ml, but only in 3/7 cases above 100 ng/ml. Autoantibodies to p53 protein were detected in 3/7 patients with HCC, but in 0/140 patients without HCC (sensitivity 42.9%, specificity 100%). In conclusion, the presence of anti-p53 was specific for malignancy and independent of AFP status. Overall, the sensitivity of serological screening for HCC in patients with hepatitis C virus-related chronic hepatitis was improved by combining AFP measurements (level > 100 ng/ml) with the detection of anti-p53.

Prevalence of hepatitis G virus and its strain variant, the GB agent, in blood donations and their transmission to recipients

BACKGROUND

Hepatitis G virus (HGV) and its strain variant, the GB agent (GBV-C) are independent isolates of a recently identified non-A through -E hepatitis virus. Prevalence in United States volunteer blood donors is 1.5 to 1.9 percent, but no data on European blood donors are available. Epidemiologic data suggest a preferred parenteral transmission route. The prevalence of HGV/GBV-C in European blood donors and the efficiency of transmission to transfusion recipients were investigated.

STUDY DESIGN AND METHODS

Plasma samples from unpaid volunteer German blood donors were tested for HGV/GBV-C by in-house reverse transcription-polymerase chain reaction. Positive donors were independently retested and interviewed for parenteral transmission risks. Amplification products were sequenced and subjected to phylogenetic analysis. Recipients of reverse transcription-polymerase chain reaction-positive donations were traced and tested for HGV/GBV-C infection.

RESULTS

A total of 14 (1.34%) of 1048 donors (alanine aminotransferase < 45 IU/L) were repeatedly positive for HGV/GBV-C with 9 (2.18%) of 413 urban and 5 (0.78%) of 635 rural donors (chi 2-test; p = 0.04). Isolates differed in nucleotide sequence homology over a range of 12.5 to 19.6 percent. All but one positive donor reported parenteral transmission risks. Transmission of HGV/GBV-C was detected in 4 of 9 transfusion recipients. The prevalence of HGV/GBV-C in donors with an alanine aminotransferase level > 45 IU per L was 3 percent (3/100). Two mother/child pairs were identified with highly homologous isolates.

CONCLUSION

A significantly greater prevalence of HGV/GBV-C was detected in urban volunteer blood donors than in rural donors. The high prevalence in urban donors (2.18%) suggests specific transmission risks for this group. The less than 50-percent efficiency of HGV/GBV-C transmission via blood components may indicate the presence of defective viruses with reduced infectivity. There is evidence for vertical transmission.