Secondary structure of DNA released from purified capsids of human parvovirus B19 under moderate denaturing conditions

Parvovirus B19 (B19V) possesses a linear single-stranded DNA genome of either positive or negative polarity. Due to intramolecular sequence homologies, either strand may theoretically be folded in several alternative ways. Viral DNA, when extracted from virions by several procedures, presents as linear single-stranded and/or linear double-stranded molecules, except when one particular commercial kit is used. This protocol yields DNA with an aberrant electrophoretic mobility in addition to linear double-stranded molecules, but never any single-stranded molecules. This peculiar kind of DNA was found in all plasma or serum samples tested and so we decided to analyse its secondary structure. In line with our results for one- and two-dimensional electrophoresis, mobility shift assays, DNA preparation by an in-house extraction method with moderate denaturing conditions, density gradient ultracentrifugation, DNA digestion experiments and competition hybridization assays, we conclude that (i) the unique internal portions of this distinctive single-stranded molecules are folded into tight tangles and (ii) the two terminal redundant regions are associated with each other, yielding non-covalently closed pseudo-circular molecules stabilized by a short (18 nucleotides) intramolecular stem, whereas the extreme 3'- and 5'-ends are folded back on themselves, forming a structure resembling a twin hairpin. The question arises as to whether this fairly unstable structure represents the encapsidated genome structure. The answer to this question remains quite relevant in terms of comprehending the initiation and end of B19V genome replication.

Temperature-sensitive origin-binding protein as a tool for investigations of herpes simplex virus activities in vivo

While it is fairly clear that herpes simplex virus (HSV) DNA replication requires at least seven virus-encoded proteins in concert with various host cell factors, the mode of this process in infected cells is still poorly understood. Using HSV-1 mutants bearing temperature-sensitive (ts) lesions in the UL9 gene, we previously found that the origin-binding protein (OBP), a product of the UL9 gene, is only needed in the first 6 hours post-infection. As this finding was just a simple support for the hypothesis of a biphasic replication mode, we became convinced through these earlier studies that the mutants tsR and tsS might represent suitable tools for more accurate investigations in vivo. However, prior to engaging in highly sophisticated research projects, knowledge of the biochemical features of the mutated versions of OBP appeared to be essential. The results of our present study demonstrate that (i) tsR is most appropriate for cell biological studies, where only immediate early and early HSV gene products are being expressed without the concomital viral DNA replication, and (ii) tsS is a prime candidate for the analysis of HSV DNA replication processes because of its reversibly thermosensitive OBP-ATPase, which allows one to switch on the initiation of DNA synthesis precisely.

Recurrent Herpetic Keratitis during Topical Acyclovir Application

Dendritic herpetic keratitis developed in a 49-year-old patient during topical acyclovir treatment. A positive herpes simplex culture was obtained. After acyclovir was replaced by trifluorothymidine and interferon, the dendritic lesion disappeared and herpes simplex culture became negative. Six months later a carcinoma of the larynx was diagnosed. The acyclovir-resistant herpetic keratitis may be associated with the carcinoma because resistant herpes simplex virus strains are predominantly described in patients suffering from immune deficiency.

Investigation of the HotDog patient warming system: detection of thermal gradients

OBJECTIVE

To assess the performance of an active patient-warming device.

MATERIALS AND METHODS

Temperatures of an active patient-warming device (HotDog system) were measured at various time points using an infrared thermometer. The study was conducted in two phases: Phase 1 compared temperatures among four different areas of the warming blanket. Phase 2 compared conditions simulating different scenarios using a weighted patient simulator.

RESULTS

Phase 1: Three out of four positions on the warming blanket had significantly different temperature measurements. Phase 2: Temperature output by the warming blanket was reduced: (1) in the absence of the patient simulator placed across the blanket (-1·9°C, P=0·013); (2) if the patient simulator was placed away from the blanket sensor (-2·0°C, P=0·009); and (3) if there was fluid between the patient simulator and warming blanket (-2·2°C, P=0·004). In a majority of measurements (95%), the set temperature of 43°C on the control unit was not reached (range, 29·8 to 42·9°C) and 2·3% of measurements were higher (range, 43·1 to 45·8°C) than the control unit set temperature of 43°C.

CLINICAL SIGNIFICANCE

Measured temperatures on the active warming blanket did not reflect control unit settings. This could result in the potential for hyperthermic injury, ineffectual heating and uneven heat distribution.

Poor immunity status against poliomyelitis in medical students: a semi-anonymous study

In spite of almost complete eradication, poliomyelitis continues to be a global threat even in non-endemic countries due to the ever-increasing international travel activities. Health care workers are at a special risk in acquiring pathogens from travelers returning from endemic countries. Polio vaccines are fairly well accepted throughout the German population. Yet, laboratory controls for successful immunization are carried out only sporadically in the general population, and not even the medical staff are routinely tested for polio immunity. The present study was initiated in order to assess the immunity status of young people at the very beginning of their career in clinical medicine. Within their first clinical semester, all students are supposed to undergo an obligatory health check in our Occupational Medicine Unit. A blood sample is taken and sent under a personal code to our diagnostic laboratories for virus serology, and for cryoconservation of residual serum, if available. Within the periods 2004–2006 and 2008–2010, we analyzed sera from 424 and 427 individuals, respectively, for anti-polio types 1, 2, 3 antibodies by a microneutralization assay. In the latest study period, there was a slight increase in the rate of fully protected persons: 63.9 % triple-seropositivity versus 57.1 % in the period 2004–2006. By the end of the second clinical semester, students with low or negative antibody levels (1:<10) were informed, and a (booster) vaccination was recommended.

Characterisation of the epitope for a herpes simplex virus glycoprotein B-specific monoclonal antibody with high protective capacity

Monoclonal antibody (MAb) 2c, specific for glycoprotein B of herpes simplex virus (HSV), had been shown to mediate clearance of infection from the mucous membranes of mice, thereby completely inhibiting mucocutaneous inflammation and lethality, even in mice depleted of both CD4(+) and CD8(+) cells. Additionally, ganglionic infection was highly restricted. In vitro, MAb 2c exhibits a potent complement-independent neutralising activity against HSV type 1 and 2, completely inhibits the viral cell-to-cell spread as well as the syncytium formation induced by syncytial HSV strains (Eis-Hübinger et al. in Intervirology 32:351-360, 1991; Eis-Hübinger et al. in J Gen Virol 74:379-385, 1993). Here, we describe the mapping of the epitope for MAb 2c. The antibody was found to recognise a discontinuous epitope comprised of the HSV type 1 glycoprotein B residues 299 to 305 and one or more additional discontinuous regions that can be mimicked by the sequence FEDF. Identification of the epitope was confirmed by loss of antibody binding to mutated glycoprotein B with replacement of the epitopic key residues, expressed in COS-1 cells. Similarly, MAb 2c was not able to neutralise HSV mutants with altered key residues, and MAb 2c was ineffective in mice inoculated with such mutants. Interestingly, identification and fine-mapping of the discontinuous epitope was not achieved by binding studies with truncated glycoprotein B variants expressed in COS cells but by peptide scanning with synthetic overlapping peptides and peptide key motif analysis. Reactivity of MAb 2c was immensely increased towards a peptide composed of the glycoprotein B residues 299 to 305, a glycine linker, and a C-terminal FEDF motif. If it could be demonstrated that antibodies of the specificity and bioactivity of MAb 2c can be induced by the epitope or a peptide mimicking the epitope, strategies for active immunisation might be conceivable.

Poor clinical sensitivity of rapid antigen test for influenza A pandemic (H1N1) 2009 virus

Influenza A pandemic (H1N1) 2009 virus RNA was detected by reverse transcription-PCR in 144 clinical samples from Bonn, Germany. A common rapid antigen-based test detected the virus in only 11.1% of these samples. The paramount feature of rapid test-positive samples was high virus concentration. Antigen-based rapid tests appear unsuitable for virologic diagnostics in the current pandemic.

Detection of influenza A(H1N1)v virus by real-time RT-PCR

Influenza A(H1N1)v virus was first identified in April 2009. A novel real-time RT-PCR for influenza A(H1N1)v virus was set up ad hoc and validated following industry-standard criteria. The lower limit of detection of the assay was 384 copies of viral RNA per ml of viral transport medium (95% confidence interval: 273-876 RNA copies/ml). Specificity was 100% as assessed on a panel of reference samples including seasonal human influenza A virus H1N1 and H3N2, highly pathogenic avian influenza A virus H5N1 and porcine influenza A virus H1N1, H1N2 and H3N2 samples. The real-time RT-PCR assay for the influenza A matrix gene recommended in 2007 by the World Health Organization was modified to work under the same reaction conditions as the influenza A(H1N1)v virus-specific test. Both assays were equally sensitive. Clinical applicability of both assays was demonstrated by screening of almost 2,000 suspected influenza (H1N1)v specimens, which included samples from the first cases of pandemic H1N1 influenza imported to Germany. Measuring influenza A(H1N1)v virus concentrations in 144 laboratory-confirmed samples yielded a median of 4.6 log RNA copies/ml. The new methodology proved its principle and might assist public health laboratories in the upcoming influenza pandemic.

Detection of influenza A(H1N1)v virus by real-time RT-PCR

Influenza A(H1N1)v virus was first identified in April 2009. A novel real-time RT-PCR for influenza A(H1N1)v virus was set up ad hoc and validated following industry-standard criteria. The lower limit of detection of the assay was 384 copies of viral RNA per ml of viral transport medium (95% confidence interval: 273-876 RNA copies/ml). Specificity was 100% as assessed on a panel of reference samples including seasonal human influenza A virus H1N1 and H3N2, highly pathogenic avian influenza A virus H5N1 and porcine influenza A virus H1N1, H1N2 and H3N2 samples. The real-time RT-PCR assay for the influenza A matrix gene recommended in 2007 by the World Health Organization was modified to work under the same reaction conditions as the influenza A(H1N1)v virus-specific test. Both assays were equally sensitive. Clinical applicability of both assays was demonstrated by screening of almost 2,000 suspected influenza (H1N1)v specimens, which included samples from the first cases of pandemic H1N1 influenza imported to Germany. Measuring influenza A(H1N1)v virus concentrations in 144 laboratory-confirmed samples yielded a median of 4.6 log RNA copies/ml. The new methodology proved its principle and might assist public health laboratories in the upcoming influenza pandemic.

Bell's palsy: combined treatment of famciclovir and prednisone is superior to prednisone alone

There is insufficient evidence concerning the efficacy of antiviral treatment of Bell's palsy (BP). We therefore compared the efficacy of prednisone and famciclovir to prednisone treatment alone in BP. A total of 167 consecutive patients with untreated acute BP were included. Severity of BP was evaluated using the House-Brackmann scale (HBS) and virus antibody tests (herpes simplex virus, varicella zoster virus) were performed. Patients admitted on even dates were treated with prednisone ("P group") and patients admitted on odd dates were treated with prednisone and famciclovir ("P+F group"). 117 patients completed the follow-up after 3 months or later (67 P/51 P+F). While most patients showed at least partial recovery with both treatment types, improvement of at least 4 grades in the HBS was more common in the "P+F group" (29.4 % vs. 11.9 %), whereas smaller changes of less than 3 grades were more common in the "P group" (29.9 % vs. 17.6 %; Chi-square test, p = 0.02). Patients with complete BP (HBS grade of 5 or 6) had significantly better chances of reaching normal function if treated with famciclovir additionally instead with prednisone alone (73.7 % vs. 47.1 %; Cochran-Armitage trend test, p = 0.03). These results suggest that the combined treatment of famciclovir and prednisolone should be considered (at least) in patients with severe BP.

Frequent detection of cell-associated HIV-1 RNA in patients with plasma viral load <50 copies/ml

Despite prolonged undetectable plasma viral load some HIV-1 infected patients have been reported to develop resistance-associated mutations leading to treatment failure. The mechanisms for this phenomenon and the point of origin for residual viral evolution are still not elucidated. In order to quantify cell-associated HIV-1 RNA in patients with different levels of plasma viremia paired cell-associated HIV-1 RNA loads and plasma viral loads were determined. Weak inverse correlation between these parameters and the amounts of CD4(+) T cells was observed, whereas there was no correlation between viral loads and CD8(+) T cells or CD14(+) monocytes, respectively. In a subset of patients, cell-associated and plasma HIV-1 env V3 sequences were analyzed. Plasma viral load and the amount of cell-associated HIV-RNA correlated strongly. However, in 62.3% of patients with undetectable plasma viral load cell-associated HIV-RNA could be detected. Analyses of HIV-RNA in plasma and blood cells showed identical sequences in 4/19 patients, whereas the majority of patients had differing HIV-1 RNA sequences in plasma and cells, respectively. In summary, this study shows that residual viral replication in peripheral blood still occurs in the majority of patients with undetectable plasma viral load. Since these replication events could lead to ongoing viral evolution it should be considered to optimize antiretroviral therapy in order to minimize the development of drug resistance.

Fifteen years of env C2V3C3 evolution in six individuals infected clonally with human immunodeficiency virus type 1

The study of the evolution of human immunodeficiency virus type 1 (HIV-1) requires blood samples collected longitudinally and data on the approximate time point of infection. Although these requirements were fulfilled in several previous studies, the infectious sources were either unknown or heterogeneous genetically. In the present study, HIV-1 env C2V3C3 (nt 7029-7315) evolution was examined retrospectively in a cohort of hemophiliacs. Compared to other cohorts, the area of interest here was the infection of six hemophiliacs by the same virus strain, that is, the infecting viruses shared an identical genome. As expected, divergence from the founder sequence as well as interpatient divergence of the predominant virus strains increased significantly over time. Based on the V3 nucleotide sequences, CCR5 usage was predicted exclusively throughout the whole period of infection in all patients. Interestingly, common patterns of viral evolution were detected in the patients of the cohort. Four amino acid substitutions within the V3 loop emerged and persisted subsequently in five (positions 305 and 308 of the HXB2 gp120 reference sequence) and six patients (positions 325 and 328 in HXB2 gp120), respectively. These common changes within the V3 loop are likely to be enforced by HIV-1 specific immune response.

Two cases of severe obstructive pneumonia associated with an HKU1-like coronavirus

BACKGROUND

During the last few years a number of previously undescribed viruses, including human metapneumovirus, coronaviruses SARS, NL63 and HKU1, and bocavirus, were identified in nasopharyngeal samples from patients with signs of respiratory infections. These viruses may cause mild to life-threatening infections.

OBJECTIVES

Nasopharyngeal samples from hospitalized pediatric patients with respiratory disease were analysed for the presence of coronaviruses and other well known and newly identified respiratory viruses.

RESULTS

Two clinical cases of a severe obstructive pneumonia, which were associated with the presence of RNA of a novel variant (subtype) of HKU1 coronavirus in the nasopharyngeal aspirates, were identified.

DISCUSSION

The detection of a HKU1-like coronavirus in pediatric patients in the current study complement the most recent independent finding of similar or closely related coronaviruses in patients with respiratory diseases in France (Vabret et al. 2006) and Norway (Jonassen et al., see accompanying manuscript). These observations indicate a wide dissemination of HKU1-like coronaviruses in Europe.

Functional domains of the human immunodeficiency virus type 1 Nef protein are conserved among different clades in Cameroon

The Nef protein of human immunodeficiency virus type 1 (HIV-1) has multiple functional domains, is immunogenic, and contains several cytotoxic T lymphocyte (CTL)-targeted epitopes. Several defined subfunctions of Nef are important for the pathogenesis of HIV-1 infection. In this study, we present the genetic diversity of the nef gene of 55 newly derived HIV-1 sequences obtained from Cameroonian patients. Four genetic subtypes and three circulating recombinant forms (CRFs) were identified: subtypes A (11%), G (7.3%), D (5.4%), F1 (1.8%), F2 (5.4%), CRF01_AE (5.4%), CRF02_AG (58.2%), and CRF11_cpx (1.8%). Two isolates clustered distinctly from the known HIV-1 genetic subtypes in nef and were designated as unclassified. Interestingly, the majority of all functional domains including the myristoylation signal, CD4 binding motif, beta turn motif, and the phosphorylation sites were well conserved in our cohort. Putative CTL-epitopic domains of the central portion of Nef were also well conserved, whereas those at the C-term were not. Our study demonstrated that despite high genetic diversity observed in the nef gene, most described functional domains and CTL epitopes were well conserved among Cameroonian HIV-1 subtypes. These findings could be used for the development of antiretroviral-acting therapeutics and anti-HIV-1 vaccines.

Comparison of GB virus C, HIV, and HCV infection markers in hemophiliacs exposed to non-inactivated or inactivated factor concentrates

BACKGROUND

Until the mandatory introduction of viral inactivation techniques of blood plasma products in the early 1980s many recipients of these products were infected with various viral pathogens.

OBJECTIVES

To determine the rate of transmission of GB virus C/hepatitis G virus (GBV-C/HGV) HCV, and HIV through non-virus-inactivated clotting factor concentrates in hemophiliacs, as well as the relation between amount of administered clotting factor and risk for GBV-C/HGV infection.

STUDY DESIGN

In this cross-sectional study, we determined retrospectively the rates of infection markers for GBV-C/HGV, HCV, and HIV in a German cohort of hemophiliacs treated with documented amounts of non-virus-inactivated clotting factor concentrates (group A) and in a second group of hemophiliacs who were treated exclusively with virus-inactivated clotting factor (group B). The presence of anti-virus antibodies was determined by ELISA. Viral RNA was detected by RT-PCR. Markers for viral infections were compared to amounts of administered non-virus-inactivated clotting factor.

RESULTS

Among hemophiliacs treated with documented amounts of non-virus-inactivated clotting factor the prevalence for GBV-C/HGV, HCV, and HIV was 40.3%, 98.6%, and 56.3%, respectively. In contrast to HIV, the rate of GBV-C/HGV infections did not increase with increasing amounts of consumed non-inactivated clotting factor. Even in the subgroup of heavily treated hemophiliacs the rate of GBV-C/HGV infection markers did not exceed 45%.

CONCLUSIONS

The amount of non-virus-inactivated clotting factor is not predictive for the risk of GBV-C/HGV infection in hemophiliacs. Despite repeated parenteral exposure more than 55% of hemophiliacs were not infected with GBV-C/HGV. Our findings indicate a high frequency of host factors preventing parenteral transmission of GBV-C/HGV.

Genome replication and progeny virion production of herpes simplex virus type 1 mutants with temperature-sensitive lesions in the origin-binding protein

Genome replication of herpes simplex viruses (HSV) in cultured cells is thought to be started by the action of the virus-encoded origin-binding protein (OBP). In experiments using two HSV-1 mutants with temperature-sensitive lesions in the helicase domain of OBP, we demonstrated that this function is essential during the first 6 hours of the lytic cycle. Once DNA synthesis has started, this function is no longer required, suggesting that origin-driven initiation of viral DNA replication is a single event rather than a continuous process.

Human metapneumovirus RNA in encephalitis patient

We describe a fatal case of encephalitis that might be correlated with primary human metapneumovirus (HMPV) encephalitis. Postmortem HMPV RNA was detected in brain and lung tissue samples from the patient. Furthermore, HMPV RNA was found in culture fluids from cells coincubated with lung tissue.

Serum antibodies against the hepatitis C virus E2 protein mediate antibody-dependent cellular cytotoxicity (ADCC)

BACKGROUND/AIMS

The role of antibody dependent cellular cytotoxicity (ADCC) in HCV infection is unclear at present. Antibodies mediating ADCC are usually directed against viral envelope proteins. As cell surface expression of the HCV envelope E2 protein has been shown, the HCV E2 protein is an especially promising candidate target for ADCC.

METHODS

Sera from patients with acute (n=6), self-limited (n=11) and chronic (n=19) HCV infection were analyzed in this study. Sera reacting with cell-bound HCV antigens were examined in a flowcytometric cytotoxicity assay using antigen-coated JOK-1 cells as targets.

RESULTS

We found that sera from all stages of HCV infection reacted with cells loaded with HCV E2. E2-specific ADCC was observed in patients with acute (n=3/6), self-limited (n=5/11) and chronic (n=13/19) hepatitis C and was closely related to fluorescence intensity in the E2-binding assay (r=0.67, P<0.001).

CONCLUSIONS

We conclude that E2-antibodies from all stages of HCV infection can mediate ADCC. Thus, the role of this process in the pathogenesis of chronic hepatitis C should be further elucidated.

New variant of the human metapneumovirus (HMPV) associated with an acute and severe exacerbation of asthma bronchiale

Recently, an increasing number of studies demonstrated that the human metapneumovirus (HMPV) causes mild to severe respiratory infections in children and immunosuppressed adults, and may be a frequent but somewhat undervalued pathogen. Here, we report the detection of a new variant of HMPV that is not closely related to the HMPV strains described until now. The strain was detected in a 6.5-year-old girl with an acute and severe exacerbation of asthma bronchiale triggered by an infection with a newly detected HMPV variant. The presented data provide new information on genetic heterogeneity of HMPV and necessitate an optimization of diagnostic procedures for the detection of HMPV infection.

Successful therapy of hepatitis B with tenofovir in HIV-infected patients failing previous adefovir and lamivudine treatment

Three HIV-infected patients with chronic hepatitis B (genotype A) were switched to adefovir therapy after unsuccessful lamivudine treatment. Surprisingly, adefovir therapy failed, although none of the virus isolates displayed mutations known to be associated with adefovir resistance (A181V, N236T). In two isolates we identified hepatitis B virus DNA polymerase mutation L217R, in one case we found multiple frameshifts in the same region. In all cases adefovir was replaced by tenofovir, resulting in a significant drop in the viral load.

Phylogenetic analysis of hepatitis C virus isolates indicates a unique pattern of endemic infection in Cameroon

Hepatitis C virus (HCV) is a blood-borne pathogen that poses a significant threat to public health worldwide. The genetic diversity and distribution of HCV genotypes in non-Western countries, particularly subSaharan Africa, is poorly documented. This study reports a phylogenetic analysis of core and NS5B gene sequences of 37 HCV strains sampled in Cameroon. A high level of genetic diversity of both genotypes 1 and 4 was found, indicating a unique pattern of long-term HCV infection that has not been observed elsewhere. These results lead to the hypothesis that these HCV genotypes originated and diversified in west Central Africa before spreading to other regions.

Transient loss of T-cell reactivity in a patient with hepatitis C virus reinfection

BACKGROUND/AIMS

Self-limited acute hepatitis C virus (HCV) infection with spontaneous recovery is only rarely observed in clinical practice. All existing studies correlate strong cellular immune responses to the recovery from HCV infection.

CASE REPORT

Here, we present a 49-year-old haemophiliac, who had successfully recovered from an acute hepatitis, which was classified retrospectively as HCV infection based on his antibody profiles. This patient was reinfected with HCV 18 years later from an exogenous source, and successfully recovered from this reinfection within 2 months. After his first hepatitis the patient displayed strong cellular responses against recombinant HCV proteins. During reinfection, T-cell proliferation was markedly reduced, while HCV antibody titres increased. However, E2 antibodies were consistently not detectable. T-cell proliferation returned to the pre-reinfection level only several months after loss of viraemia.

DISCUSSION

Our observations resulted in the unexpected finding that our patient cleared HCV reinfection despite an apparent loss of his pre-existing T-cell reactivity in the peripheral blood.

[Do polymorphisms of the SDF1 and CCR2b genes modify the course of hepatitis C or HIV/HCV co-infection?]

BACKGROUND AND OBJECTIVE

Complementary to the CCR5-Delta32 mutation polymorphisms in the genes of CCR2b (CCR2b-V64 I) and stromal derived factor (SDF)-1 (SDF-1 3'A) affect the course of the human immunodeficiency virus (HIV) infection. While the CCR5-Delta32 mutation is also increased in chronic hepatitis C virus (HCV) infection it is unclear, whether the CCR2b-V64 I and the SDF-1 3'A polymorphisms also are associated with chronic HCV infection.

METHODS

We analyzed the frequencies of the CCR2b-V64I and SDF1 - 3'A mutation in patients with HIV/HCV coinfection (n = 130), HIV infection (n = 105), HCV infection (n = 153) and 112 healthy blood donors. We stratified each group into homozygous mutations, heterozygous mutations and homozygous wild types, respectively. The resulting subsets were compared with respect to HIV and HCV loads, CD4 and CD8 cell counts.

RESULTS

The mutant SDF1 - 3'A allele was found at 20.3 % frequency in patients with HCV infection and at 20.4 % frequency in patients with HIV/HCV coinfection, respectively. It was present in 27.1 % of the patients with HIV infection and 27.9 % of the healthy controls (not significant). The number of SDF-1 3) A homozygous patients was highest in patients with HIV/HCV coinfection and significantly different compared to the Hardy-Weinberg equilibrium (p = 0.010, chi (2) = 9.15). However, CD4- and CD8-cell counts or viral loads were not affected by this mutation. The frequency of the CCR2b-V64 I allele was similar in all patient groups. However, CCR2b-V64 I heterozygous patients showed HIV loads that were threefold lower than in CCR2b wildtype patients (22.9 x 103 vs. 6.4 x 103 copies/ml, not significant). Furthermore, hepatitis C viral loads were reduced roughly by 30 %.

CONCLUSION

These results suggest that the SDF1 - 3'A and CCR2b-V64I mutations do not affect the course of HCV and HIV/HCV infection in the same manner as does the CCR5-Delta32 mutation.

Differential expansion of T-cell receptor variable beta subsets after antigenic stimulation in patients with different outcomes of hepatitis C infection

Persistent antigenic stimulation during chronic hepatitis C may alter the T-cell receptor variable chain beta (TCR BV) repertoire as well as the cytokine responses of hepatitis C virus (HCV)-specific T lymphocytes. We analysed the distribution of the TCR BV subsets 2.1, 3.1, 5.1, 6.1, 8, 13.1, 13.6, 14.1, 17.1, 21.3 in relation to intracytoplasmic expression of interleukin-2, interferon-gamma, interleukin-4 and interleukin-10. Using flow cytometry, CD45RO+ memory T cells of 27 patients with chronic hepatitis C, eight patients with resolved HCV infection and 16 non-HCV-related controls were studied with and without stimulation by the HCV core, NS3, NS4, NS5a and NS5b proteins. Patients with chronic and resolved hepatitis C differed by larger basal TCR BV2.1+, BV6.1+, BV17.1+ and BV21.3+ subsets in chronic hepatitis C, which were correlated to the numbers of T cells with spontaneous interleukin-2 and interferon-gamma production (r=0.51-0.73, P<0.05). Upon HCV-specific stimulation these subsets did not expand, whereas a marked in vitro expansion of TCR BV8+ T cells in response to all HCV proteins was selectively noted in chronic hepatitis C (P<0.05). This expansion of TCR BV8+ memory T cells was significantly correlated to HCV-induced interleukin-10 expression (r=0.58-0.98, P<0.01). Thus, differential involvement of selected TCR BV subsets may be related to the outcome of HCV infection.

HCV-specific cytokine induction in monocytes of patients with different outcomes of hepatitis C

AIM: Cytokine release by macrophages critically determines the type of immune response to an antigen. Therefore, we studied hepatitis C virus (HCV)-specific induction of interleukins-1β, -10, -12 (IL-1β, IL-10, IL-12), and tumor necrosis factor-α (TNF-α) in monocytes.

METHODS: Intracellular cytokine expression was studied by flow cytometry in 23 patients with chronic hepatitis C, 14 anti-HCV seropositives without viremia and 11 controls after stimulation of peripheral blood mononuclear cells with recombinant core, NS3, NS4, NS5a and NS5b proteins.

RESULTS: Patients with HCV viremia revealed greater spontaneous expression of IL-1β, TNF-α, and IL-10. Furthermore, greater than twofold higher IL-10 expression was induced by the HCV antigens in chronic hepatitis C than in the other two groups (P < 0.05). In contrast, neither IL-12 nor TNF-α was induced preferentially.

CONCLUSION: In chronic hepatitis C antigen-specific cytokine induction in monocytes is apparently shifted towards predominant IL-10 induction - not counterbalanced by antiviral type 1 cytokines. This may contribute to persistent viral replication.

Risk of hepatitis C after immunoadsorption

An episode of acute hepatitis in a patient with hemophilia during immunoadsorption therapy initially was misinterpreted as a reactivated hepatitis C virus (HCV) infection, but ultimately was shown to be an exogenous reinfection during cohort treatment with another HCV-positive patient. This incident illustrates that policies for the prevention of nosocomial transmission of blood-borne pathogens, especially in cohort treatment units, may need to be reassessed.

Frequency of the HIV-protective CC chemokine receptor 5-Delta32/Delta32 genotype is increased in hepatitis C

BACKGROUND & AIMS

A homozygous 32-base pair deletion in the CCR5 gene (CCR5-Delta32) protects against human immunodeficiency virus infection (HIV). However, the role of this mutation in other infections, such as hepatitis C virus (HCV) infection, has not been defined.

METHODS

We determined the frequency of the CCR5-Delta32 mutation by polymerase chain reaction in anti-HCV(+) (n = 153), anti-HIV(+) (n = 102), and anti-HCV(+)/HIV(+) (n = 130) white patients as well as in 102 healthy blood donors. Then, HIV and HCV loads, aminotransferases, and CD4 and CD8 cell counts were compared between the resulting subsets of CCR5-Delta32/wild-type heterozygotes, CCR5-Delta32, and wild-type homozygotes, respectively.

RESULTS

Twelve of 153 (7.8%) anti-HCV-seropositive patients and 1 of 102 (1.0%) healthy blood donors were CCR5-Delta32 homozygous, whereas CCR5-Delta32 homozygosity was absent in anti-HIV(+) and anti-HCV(+)/HIV(+) patients (P < 0.001). The frequency of the CCR5-Delta32 allele was higher in the anti-HCV(+) (16.0%, P < 0.05) and anti-HCV(+)/HIV(+) (12.7%, NS) patients than in healthy blood donors (8.3%) and anti-HIV(+) patients (9.3%), respectively. Anti-HCV(+) CCR5-Delta32 homozygotes occurred 3 times more frequently than expected from the Hardy-Weinberg equation (P < 0.0001) and had significantly higher HCV loads than wild-type patients (P = 0.045).

CONCLUSIONS

The increased prevalence of CCR5-Delta32 homozygosity associated with increased viral loads in patients with chronic hepatitis C suggests that the CCR5-Delta32 mutation may be an adverse host factor in hepatitis C.

Hepatitis C virus infection and genotypes among human immunodeficiency virus high-risk groups in Cameroon

Parenteral transmission of HCV is well established but other possible routes such as heterosexual transmission are still questioned. The Central African region is characterised by a high HCV endemicity without any evidence on the route of transmission. The information on HCV genotypes that circulate in this area is also limited and controversial. HIV infection is very frequent in this region and mostly acquired via the heterosexual route. The aim of this work was to investigate the trend of HCV infection and genotypes among HIV high-risk groups from Cameroon. Four hundred eighty-two patients including 229 tuberculosis clinic attendants, 184 sexually transmitted disease clinic attendants, and 69 HIV clinical suspects from another clinic were enrolled. All plasma samples were screened for antibodies to HCV and HCV RNA. Genotypes were assigned by sequencing a 5'UTR amplified fragment. The overall prevalence of HCV markers was 11.6% and a significant increasing trend with respect to age was observed. A proportion of 64.1% (34/53) of HCV antibody positive samples was viraemic. HCV RNA was found in 3 samples that were indeterminate in RIBA 3.0. One was negative in the antibody screening test and the two others were weakly positive. The data on HCV genotypes revealed that genotype 1 was involved in 57% of viraemias, genotype 2 in 24%, while genotypes 4 and 5a accounted for 16 and 3%, respectively. In contrary to the predominance of genotype 4 reported in some African countries and even the neighbouring countries, these data demonstrate clearly that HCV infection in Cameroon is dominated by genotypes 1 and 2. No association was found between the HCV markers and the presence of HIV infection. It is concluded, therefore, that the heterosexual route plays a minor role in HCV transmission in this country.

Structure of simian virus 40 DNA replicated by herpes simplex virus type 1

Replicating herpes simplex virus type 1 (HSV-1) DNA is known to form large branched structures. The aim of this study was to define whether HSV-1-specific DNA elements in cis play a critical role in formation of this structure. We did this by investigating the structure of heterologous simian virus 40 (SV40) DNA, which is replicated in HSV-infected cells by SV40 large T-antigen and defined HSV-encoded replication factors (e.g., DNA polymerase, single-stranded DNA-binding protein, and helicase-primase). During this process, extrachromosomal concatemeric DNA replication products are formed, indicating a herpesvirus-specific replication mode. In this study, we found that the replicating SV40 DNA consisted of a complex branched structure indistinguishable from that of replicating HSV DNA. Thus, no HSV-specific DNA element is necessary in cis for the formation of the large branched structure during HSV DNA replication. The trans-acting HSV DNA replication proteins seem to be sufficient to generate these complex structures. Moreover, replicating SV40 DNA showed a high frequency of homologous recombination events, which is typical for HSV DNA replication. However, in contrast to HSV origin-bearing amplicon plasmids, SV40 plasmids bearing the HSV cleavage-packaging signal were not efficiently processed to linear 150-kb DNA packaged into HSV capsids. This indicates that initiation of DNA synthesis on HSV-ori determines some, yet undefined, property of replicating HSV DNA, which is crucial for regular processing of the replication intermediates to daughter genomes.

Antigen-specific cytokine response to hepatitis C virus core epitopes in HIV/hepatitis C virus-coinfected patients

OBJECTIVE

Epidemiological data indicate that hepatitis C virus (HCV) infection runs a more rapid and severe course of disease in HIV-coinfected patients, probably because of an altered immune response.

DESIGN

We investigated whether HCV-specific cytokine responses are affected by HIV coinfection.

METHODS

Using triple colour flow cytometry on peripheral blood lymphocytes after stimulation with the four major immunodominant HCV core T cell epitopes, CT1-CT4, we determined intracytoplasmic production of IFN-gamma, IL-2, IL-4, IL-10 and CD30 expression, a putative surrogate marker of type 2 cells. Fifteen patients with asymptomatic HIV/HCV coinfection (group A), 15 patients with chronic HCV infection (group B) and 10 HIV-infected patients without hepatitis C (group C) were included in the study.

RESULTS

In group A, HCV antigens induced significantly higher IL-2 and IFN-gamma production than groups B and C (P < 0.05). Groups A and B showed a similar induction of CD30, which was significantly higher than in group C (P < 0.001). Remarkably, in group A HCV antigens induced IL-4 production in addition to IL-10 and IFN-gamma in the CD30 subset, whereas in groups B and C no IL-4 induction was observed in this T cell subset (P < 0.002).

CONCLUSION

Our data suggest that asymptomatic HIV coinfection importantly alters the HCV-specific cytokine response towards a greater production of proinflammatory type 1 cytokines. Moreover, the antiviral activity of type 1 cytokines may be modified by an increased production of type 2 cytokines in the CD30 subset. The altered cytokine pattern may contribute to the adverse natural course of hepatitis C in HIV coinfection.

Protection against parenteral HIV-1 infection by homozygous deletion in the C-C chemokine receptor 5 gene

OBJECTIVES

To investigate the role of the CC chemokine receptor 5 (CCR5) for parenteral transmission of HIV-1.

DESIGN

The prevalence of the delta32 deletion within the CCR5 gene was determined in a cohort of 207 patients, who had received documented amounts of non-antibody-tested and non-inactivated clotting factor concentrate.

METHODS

Chromosomal DNA of haemophiliacs was isolated from whole blood. A portion of the CCR5 gene spanning the delta32 deletion was amplified by PCR. The resulting DNA fragments were analysed by agarose gel electrophoresis.

RESULTS

The rate of HIV-1 infection was correlated strongly with increasing amounts of inoculated clotting factor concentrate. None of the HIV-positive patients (n = 129) had the delta32/delta32 genotype, whereas 12 out of 78 HIV-negative haemophiliacs had the homozygous delta32 deletion.

CONCLUSIONS

The delta32/delta32 genotype was highly protective against HIV-1 infection, even in patients who had received millions of non-inactivated clotting factor units. As it is likely that in the early 1980s plasma pools were contaminated not only with monocyte-tropic HIV-1 strains, CCR5 appears to be the major mediator of HIV-1 infection. Furthermore, we conclude that there must be other protective mechanisms in multiply exposed non-infected haemophiliacs who have wild-type CCR5.

Evaluation of three glycoprotein G2-based enzyme immunoassays for detection of antibodies to herpes simplex virus type 2 in human sera

Three new glycoprotein G-based enzyme immunoassays (ETI-HSVK-G 2, Sorin Diagnostics Biomedica [assay A]; HSV Type 2 Specific IgG ELISA, Gull Laboratories, Inc. [assay B]; Cobas Core HSV-2 IgG EIA, Roche [assay C]) for the detection of herpes simplex virus (HSV) type 2 (HSV-2)-specific antibodies were evaluated. By testing sera from 25 individuals with culture-proven HSV-2 infection, the assays showed a sensitivity of 96%. The specificities, evaluated with sera from 70 HSV antibody-negative children, 75 HSV antibody-positive children, and 69 HSV antibody-negative adults, were 100% for assay A, 96.2% for assay B, and 97.8% for assay C, respectively. Discrepant results by any of the three assays, i.e., reactivity of a specimen in only one or two assays, occurred with similar frequencies for HSV-seronegative individuals as well as HSV-seropositive children and adults. For sera with discrepant results, the positive reactivity was mostly low. Thus, for determination of the prevalence of HSV-2 antibodies, only concordantly positive results were considered. On the basis of the results obtained with sera from 41 adults with culture-proven HSV-1 infection and from 173 HSV-antibody-positive pregnant women, the HSV-2 seroprevalence was 9. 8%. The results show that the new glycoprotein G2-based enzyme immunoassays are useful tools for the detection of type-specific HSV-2 antibodies. However, if only one assay is performed, careful interpretation of the results is indicated, especially if the exhibited reactivity is low, and for determination of the definitive HSV-2 serostatus, confirmatory assays may still be necessary.

Role of HIV-1 phenotype in viral pathogenesis and its relation to viral load and CD4+ T-cell count

The predictive value of HIV-1 phenotype in peripheral blood mononuclear cell (PBMC) coculture and the relation among viral phenotype, viral load, and CD4+ T-cell count were examined in two studies. In study A, 132 HIV-1-infected individuals were examined retrospectively for the relation between the result of their initial HIV cultivation in PBMC coculture and survival rate 6 years later. In study B, 176 patients were examined since 1994 for markers of HIV disease progression. HIV-1 phenotype was determined by PBMC cocultivation, viral load by NASBA HIV RNA QT System, and CD4+ T-cell count by flow cytometry. In study A, the percentage of survival for patients with initial negative virus culture was significantly higher (95%) than in patients with nonsyncytia-inducing (NSI) isolates (78%) and syncytia-inducing (SI) isolates (21%) (P < 0.05 and P< 0.0001, respectively). When SI phenotype was subdivided into moderately cytopathogenic and highly cytopathogenic, significant differences in the rate of survival between these subgroups could be observed (45% vs. 14%; P < 0.05). In study B, progression from negative virus culture to the isolation of NSI variants was associated with increasing viral load (P < 0.0001) but did not affect CD4+ T-cell count significantly (P> 0.07), whereas the switch from NSI to SI virus was accompanied by significant decline of CD4+ T-cells (P < 0.0001) but no change in viral load (P > 0.21). Thus, isolation and phenotyping of HIV represents an additional striking predictive marker for progression of HIV infection.

Transformation of rodent fibroblasts by ICP4, the major transactivating protein of herpes simplex virus type 1

Rat fibroblasts were transfected with a plasmid containing the IE3 gene derived from the temperature sensitive HSV-1 mutant tsK. Three of four clones expressing biologically active, temperature-sensitive ICP4, formed a substantial number of colonies in soft agar at the permissive temperature. During the first passages of cells, the transformed state of the major proportion of transformed cells was dependent on the continuous activity of ICP4. In a smaller and distinct subpopulation of transformed cells, as well as after longer subcloning of cells, ICP4 was no longer required for the maintenance of the transformed state, pointing to the induction of stable genomic changes by ICP4. Our data show that ICP4 of HSV-1 is involved in transformation of fibroblasts. Transformed cells are, however, subject to intracellular and intercellular control mechanisms.

HIV colonizing peripheral blood monocytes follows lymphocytic isolates in shifting from NSI to SI genotype

Non-syncytium inducing (NSI) and syncytium inducing (SI) variants of human immunodeficiency virus (HIV) isolated from peripheral blood mononuclear cells (PBMC) could be definitely typed by sequence analysis of the env-gene V3 region. It was thus possible to compare the genotypes of viral variants isolated from PBMC and accompanying monocyte cultures and those derived directly from the patients' blood cells prior to cultivation. Within the investigated group of patients it was shown that HIV variants colonizing monocytes displayed a similar shift from NSI to SI as observed previously for PBMC, i.e. lymphocyte derived isolates. Lymphocytic SI variants could be isolated from the blood of patients, while simultaneously the predominant provirus in both blood and monocytic isolate was NSI. Consequently, we observed a delayed switch in the predominant provirus genotype found in blood which was associated with a synchronous change in the genotype of the corresponding monocytic isolate. The results show that monocytes/macrophages can be colonized by heterogeneous HIV variants in vivo and can therefore also function as carriers for the spread of highly virulent SI variants into the tissues.

T- and B-cell responses to different hepatitis C virus antigens in patients with chronic hepatitis C infection and in healthy anti-hepatitis C virus--positive blood donors without viremia

As the host's immune response may determine the course of hepatitis C virus (HCV) infection, we studied the humoral and cellular immune responses to HCV-related antigens in subjects with different outcomes of HCV infection. Lymphoproliferative responses and circulating antibodies to a panel of HCV core- and E1-related 25-mer peptides were examined in 10 healthy anti-HCV-seropositive blood donors (group A) and in 29 patients with chronic hepatitis C (group B). In addition, cellular recognition of recombinant HCV proteins (core, NS3, NS4A, NS5A, NS5B) were investigated. In group A, stronger T-cell responses were detected against both HCV proteins (core, P = .03; NS4, P = .005; NS5B, P = .03) and peptides. Proliferation was induced by the same peptides in each group, defining at least five distinctive epitopes within core (amino acids [aa] of 20-44, aa 39-63, aa 79-103, aa 118-152 and aa 148-172) and three regions within E1(aa 198-252, aa 308-372, and aa 368-392). Subjects with strong T-cell responses had low or no detectable levels of peptide-specific antibodies, and vice versa. In particular, T-cell responses were more common in group A; B-cell responses were more common in group B. From our data, we conclude that a benign course of HCV infection may be the consequence of the effective activation of T-helper lymphocytes.

The prevalence of antibody to parvovirus B19 in hemophiliacs and in the general population

The prevalence of antibodies to parvovirus B19 (B19) was measured in the sera of 566 hemophiliacs and 524 individuals of the general population by immunofluorescence assays, using antigen expressed by the baculovirus system. In the general population, anti-B19 IgG seroprevalence was found to continuously decline from 64 percent at birth to 0 percent in the age of 9-11 months and thereupon to increase to 61 percent in the age of 12 years. In younger adults and older people, IgG seroprevalence only slowly increased with age, reaching 77 percent in people aged 60 and above. In contrast, in hemophilic children treated exclusively with virally inactivated clotting factor concentrates, neither decrease nor increase of B19 IgG antibody was detectable and the overall seroprevalence was 92 percent. In the group of hemophiliacs older than 12 years and treated before 1984 with non-inactivated clotting factor concentrates, 98 percent showed antibody to B19. Anti-B19 IgM seroprevalence was significantly higher in hemophilic than in non-hemophilic individuals older than 12 years. Since it seems to be unlikely that the high seroprevalence in hemophiliacs is acquired by immunization with inactivated viral antigen, the results suggest that infection with B19 is transmitted by clotting factor concentrates, even if subjected to virucidal methods.

Biological testing versus sequence analysis for determination of drug resistance of human immunodeficiency virus

Resistance of HIV-1 to 3'-azido-3'-deoxythymidine (AZT) is associated with one or more of five mutations in the reverse transcriptase (RT) segment of the polymerase gene ("AZT-specific mutations"). Therefore, sequence analysis of the proviral DNA, derived directly from the blood, is considered to replace the biological test. Additional arguments are non-cultivatable viral strains, the universality of the sequence analysis in combination therapy, and the suspicion that the cultivated virus does not represent the predominant viral variant in the blood. In this investigation, 21 strains of human immunodeficiency virus type 1 (HIV-1) were comparatively analysed by molecular and biological testing. For 12 strains, the homology of the RT gene segment between the predominant provirus in the blood and the cultivated virus was ascertained (99.72% homology). 11 strains from untreated patients or patients treated no longer than 5 months were free from AZT-specific mutations and proved to be sensitive. 10 strains from patients treated for 17 to 57 months displayed 2-4 AZT-specific mutations. However, it was not possible to correlate the degree of sensitivity to the number or the pattern of the mutations. Suppression of AZT resistance by strain-specific sequences in other parts of the gene are discussed as the reason for that discrepancy. Remarkably, the productivity of resistant virus strains could be drastically enhanced by non-inhibiting concentrations of the drug.