[Viral markers of hepatitis B, C and D and HB vaccination status of a health care team in a rural district of Cameroon]. / Marqueurs d'infection par virus des hépatites B, C et D et vaccination contre l'hépatite B chez des personnels de santé d'un district rural du Cameroun.

UNLABELLED: Ninety-three health care workers (HCW) in the Tokombere sahelian district volunteered to participate in a trial to investigate viral markers of hepatitis B, C, and D and HB vaccination status. METHODS: . Sera were tested using the Vikia HBsAg kit followed by CMIA for detection of HBsAg, anti-HBs, anti-HBc, and anti-HCV. HBsAg-positive HCW were tested for HBV-DNA, anti-HDV, and, if positive for anti-HDV, HDV-RNA. RESULTS: Analysis of anti-HBc positivity indicated that 91% of HCW had been infected by HBV, regardless of vaccination history. Vikia HBsAg results were confirmed by chemiluminescent microparticle immunoassay (CMIA) in all HCW and were positive in 17 HCW with virus load >2000 IU/mL in 6 and HDV co-infection in 6. Anti-HCV was found in 6 HCW. Among the 55 HCW that had not been vaccinated, only 3 needed vaccination because of anti-HBc negativity. Among HCW considered for HBV treatment, one patient presenting HBV/HDV co-infection was excluded after diagnosis of hepatocarcinoma. CONCLUSION: Systematic HB vaccination of new HCW appears unnecessary in this rural region of Africa. Anti-HBc screening is cost-effective for identifying HCW requiring vaccination. Vikia HBsAg is effective for point-of-care screening. We underline the need for universal early (preferably neonatal) HB vaccination and for availability of anti-HBV drug in limited-resource countries.

P-glycoprotein in blood CD4 cells of HIV-1-infected patients treated with protease inhibitors.

OBJECTIVE: Many factors are involved in the virological failure of antiretroviral treatments such as low pharmacological plasma levels of drugs, poor adherence to therapy and emergence of viral resistance. P-glycoprotein (P-gp) has been demonstrated to play a role in multidrug resistance in the therapy of solid tumours, haematological malignancies and Plasmodium falciparum infection. HIV-1 protease inhibitors (PIs) have been described to be substrates of P-gp. In vitro and in vivo studies performed in mice have demonstrated that P-gp may affect the oral bioavailability and intracellular accumulation of PIs. P-gps have been detected on peripheral CD4 blood cells in HIV-1-infected, but antiretroviral-naive patients. METHOD: We quantified P-gp expression and performed functional tests of P-gp activity in the CD4 cells in HIV-1-infected patients, with and without virological failure, treated with PIs, and in healthy patients (control group). RESULT: Out of the 18 HIV-infected patients studied, P-gp expression and function were found in the CD4 cells of six patients (four of 10 without, and two of eight with virological failure). Out of the 43 healthy patients studied, P-gp expression and function were found in the CD4 cells of 11 patients (26%). We found P-gp in peripheral CD4 cells of patients treated with PIs, with and without virological failure, within the same frequency than in antiretroviral naive patients or than in non HIV-infected patients. CONCLUSIONS: P-gp expression in peripheral CD4 blood cells does not seem to be enhanced by PI treatment and does not seem to be linked particularly to virological failures. These facts do not preclude of the role of P-gp on PI absorption or efficacy in other compartments of the body such as gut, lymph nodes or brain in HIV-1 PI-treated patients.

Effects of cyclosporine and hydrocortisone on Kaposi's sarcoma-associated herpesvirus genome replication and cell apoptosis induction.

BACKGROUND: Iatrogenic immunosuppressed patients are at increased risk for development of various cancers that comprise Kaposi's sarcoma (KS). METHODS: To investigate the direct impact of immunosuppressive agents on Kaposi's sarcoma-associated herpesvirus (KSHV) and KS development, we quantified the effects of cyclosporine (CsA) and hydrocortisone (HC) on KSHV genome replication and the consequences on the cell survival. RESULTS: In the presence of phorbol ester 12-O-tetradecanoyl phorbol-13-acetate, we observed an increase of intracellular and extracellular KSHV DNA concomitantly with an increase of gp (glycoprotein) K8.1 expression, indicating KSHV genome replication. This replication was accompanied by cell apoptosis. In comparison, in the presence of CsA, HC, or both, we did not observe any effect on KSHV replication or gp K8.1 expression. CONCLUSION: Our results suggest that immunosuppressive agents such as HC and CsA do not activate the lytic cycle of KSHV and do not modify the cell survival thus promoting cancer progression by a direct cellular effect.

Efficacy of dideoxynucleosides against human foamy virus and relationship to its reverse transcriptase amino acid sequence and structure.

Human foamy virus (HFV), a retrovirus of simian origin which occasionally infects humans, is the basis of retroviral vectors in development for gene therapy. Clinical considerations of how to treat patients developing an uncontrolled infection by either HFV or HFV-based vectors need to be raised. We determined the susceptibility of the HFV to dideoxynucleosides and found that only zidovudine was equally efficient against the replication of human immunodeficiency virus type 1 (HIV-1) and HFV. By contrast, zalcitabine (ddC), lamivudine (3TC), stavudine (d4T), and didanosine (ddI) were 3-, 3-, 30-, and 46-fold less efficient against HFV than against HIV-1, respectively. Some amino acid residues known to be involved in HIV-1 resistance to ddC, 3TC, d4T, and ddI were found at homologous positions of HFV reverse transcriptase (RT). These critical amino acids are located at the same positions in the three-dimensional structure of HIV-1 and HFV RT, suggesting that both enzymes share common patterns of inhibition.

Preferential associations of alleles of three distinct genes argue for the existence of two prototype variants of human herpesvirus 7.

We had previously described six distinct alleles of the glycoprotein B (gB) gene of human herpesvirus 7 (HHV-7). The genetic changes corresponding to these alleles did not affect gB gene transcription or translation in in vitro assays. The study of distinct HHV-7-positive human samples showed preferential associations of some gB alleles with some alleles of two other genes, distantly located on the HHV-7 genome, coding for the phosphoprotein p100 (p100) and the major capsid protein (MCP). Two allele combinations, corresponding to 44 and 31% of the samples studied, respectively, were interpreted as the genetic signatures of two major prototype HHV-7 variants.

The influence of highly active antiretroviral therapy on AIDS-associated Kaposi's sarcoma.

To assess the clinical and biological benefit of highly active antiretroviral therapy on AIDS-associated Kaposi's sarcoma (KS), 13 patients with AIDS-associated Kaposi's sarcoma (five pulmonary KS and eight cutaneous KS) were prospectively followed for a mean duration of 12 months. Six patients were treated with specific anti-KS chemotherapy before or simultaneously with the introduction of antiretroviral therapy. Clinical response was assessed according to the AIDS Clinical Trial Group (ACTG) criteria. CD4 cell counts, plasma HIV-1 RNA and human herpesvirus 8 (HHV-8) viraemia were measured at baseline and at different points. Among patients with pulmonary KS, we observed three complete responses (CR), one partial response (PR) and one progression. The median survival time after the diagnosis of pulmonary KS was 15 months with a median duration of the response after the discontinuation of specific chemotherapy for KS of 8 months. Among patients with cutaneous KS, we observed four CR, three PR and one stable response. A complete response was significantly associated with a reversal in HHV-8 viraemia (five of six vs. one of six; P = 0.02, Mann-Whitney test).

Transfusion-associated or nosocomial hepatitis G virus infection in patients undergoing surgery.

BACKGROUND: Despite blood donor screening, there are still cases of transfusion-associated hepatitis. From 1988 to 1992, a prospective study was conducted on the incidence of non-A, non-B posttransfusion hepatitis (PTH). STUDY DESIGN: The present investigation was designed to determine if transfusion recipients with PTH who are negative for hepatitis C virus (HCV) were positive for hepatitis G virus (HGV). Patients admitted for surgery who had normal liver tests and no transfusions during the previous 6 months were enrolled. Alanine amino transferase levels were determined monthly for 6 months after surgery and for 1 year in the case of PTH (defined as alanine aminotranferase twice the upper limit of normal in two consecutive assays). HGV RNA and E2 antibodies were tested for in samples from transfusion recipients with or without PTH and from nontransfused patients. RESULTS: Of the 308 blood recipients who were enrolled in the study, 21 (6.8%) had PTH. HGV RNA was detected at the onset of hepatitis in 3 patients with PTH (14%), 2 of whom were also anti-HCV and HCV RNA positive. One patient developed E2 antibodies without detectable HGV RNA. Three (10.7%) of 28 recipients of an allogeneic transfusion without PTH developed HGV infection. HGV RNA was also found in two nontransfused patients, which suggests nosocomial transmission of HGV. CONCLUSION: Some cases of PTH are associated with HGV; most cases of postoperative HGV infection are not associated with liver abnormalities; and most PTH cases are not associated with known hepatotropic viruses.

Definition and distribution analysis of glycoprotein B gene alleles of human herpesvirus 7.

As for other herpesviruses, glycoprotein B (gB) of human herpesvirus 7 (HHV-7) is believed to play a major role in virus infection and as a target of the host immunogenic response. Using nested PCR, we amplified the whole HHV-7 gB gene from 108 human peripheral blood mononuclear cell samples and studied its variability. By means of restriction fragment length polymorphism (RFLP) analysis, three distinct patterns, designated I, II, and III, were defined and detected at frequencies of 93, 5, and 2%, respectively. Determination of the nucleotide sequence allowed us to recognize five critical positions in the gB gene with six specific combinations of point changes at these positions. These combinations were gB alleles A, B, C, D, E, and F. Alleles D and E corresponded to RFLP patterns II and III, respectively, while the other four alleles corresponded to RFLP pattern I. Identical gB alleles were detected in serial samples as well as in paired samples of blood and saliva from the same individuals, except for one case. In contrast, the distribution of gB alleles differed according to the geographical origin of the human samples: C was the most frequent allele in both African and Caribbean samples, whereas F was the most frequent allele in European ones. Although none of the allele-specific nucleotide changes induced any modification at the protein level, the definition of gB alleles provided convenient viral markers for the study of both HHV-7 infections and human population genetics.

[Absence of HHV-8 virus detected in immature hemangiomas in infants]. / Absence de détection du virus HHV-8 dans les hémangiomes immatures du nourrisson.

INTRODUCTION: The aim of our study was to search for the presence of HHV-8 DNA sequences in Biopsy specimens from hemangioma of the infancy. MATERIAL AND METHODS: The study included 9 biopsies from hemangioma. DNA of human beta-globin gene and HHV-8 were searched for by PCR using specific primers. Amplified products were revealed after an hybridization with an internal probe digoxigenin-labelled. RESULTS: Human beta-globin gene could be detected in all samples illustrating the absence of PCR inhibitor. HHV-8 could never be detected in samples analyzed. DISCUSSION: Our study does not imply any causative role of HHV-8 in the pathogenesis of hemangioma. This result must be confirmed by serologic studies.

[Acyclovir-resistance zona in a immunocompromised HIV seronegative patient]. / Zona résistant à l'aciclovir chez un malade immunodéprimé non infecté par le VIH.

INTRODUCTION: Resistance to antiviral therapy is getting actually more frequent. Immunocompromised host are more concerned with this problem. OBSERVATION: We present a case of disseminated zoster resisting to acyclovir (ACV) therapy, but healing with foscarnet in a man treated with chemotherapy for lymphoma and seronegative for HIV. CI50 of VZV strain was 48 microM for ACV, which was 2.8 times higher than value of the reference OKA strain tested simultaneously, which confirmed the resistance for ACV. DISCUSSION: Immunocompromised patients often present varicella zoster virus (VZV) infection. They usually heal in response to ACV therapy, but some HIV infected patients have already presented with resistant strains of VZV. This case is the first described in a non-HIV infected patient. Foscarnet therapy resulted twice in complete healing because of its direct activity on viral DNA polymerase, so it is efficaceous therapy for patients with thymidine-kinase-deficient ACV-resistant VZV infection.

Acyclovir-resistant varicella-zoster virus: phenotypic and genetic characterization.

A man with acquired immunodeficiency syndrome (AIDS) developed zoster of the right arm which was resistant clinically to acyclovir. Varicella-zoster virus (VZV) was cultured from a skin biopsy performed at the beginning of acyclovir therapy (isolate 1) and after its failure (isolate 2). The emergence of acyclovir resistance during treatment was investigated by developing a simple and rapid drug sensitivity assay based on the plaque reduction reference method. This late-antigen synthesis reduction assay involved serial dilutions of cell-associated virus. The 50% inhibitory concentration (IC50) of acyclovir was 16 +/- 7.5 microM for the susceptible reference strain OKA, in agreement with published data. The acyclovir IC50 increased from 6.5 microM for isolate 1 to 100 microM for isolate 2. In comparison with the sequence of isolate 1, isolate 2 had a single mutation consisting of a C to T change at position 907 of the thymidine kinase gene, which changed a glutamine codon into a stop codon at position 303 of the thymidine kinase protein. These results show the emergence of acyclovir resistance through a single previously undescribed mutation in the thymidine kinase gene, and confirm the heterogeneity of mutations inducing acyclovir resistance.

Prevalence of human herpesvirus 8 infection measured by antibodies to a latent nuclear antigen in patients with various dermatologic diseases.

BACKGROUND: Human herpesvirus 8 (HHV-8) has been detected in all epidemiological forms of Kaposi sarcoma (KS). The role of HHV-8 in dermatologic diseases other than KS is controversial. Some studies based on polymerase chain reaction findings suggest an association between HHV-8 and epithelial tumors of the skin, lymphoproliferative disorders, or pemphigus. OBJECTIVE: To assess the prevalence of antibodies against a latent nuclear antigen of HHV-8 in patients with various dermatologic diseases. DESIGN: An indirect immunofluorescence assay was used to search for HHV-8 antibodies. SETTING: Ambulatory or hospitalized patients from a university hospital associated with a research laboratory. PATIENTS: Eighty-three patients with various non-KS dermatologic diseases and 16 patients with KS who were seronegative for the human immunodeficiency virus. Controls were 100 healthy subjects living in the same area. RESULTS: Antibodies to HHV-8 were found in 100% (16/16) of the patients with KS and 3.6% (3/83) of the patients with non-KS dermatologic diseases: 1 patient with pemphigus vulgaris, 1 with discoid lupus erythematosus, and 1 with bullous pemphigoid. The prevalence of antibodies to HHV-8 in controls was 2% (2/100) and was not significantly different than the prevalence in patients with dermatologic diseases other than KS (P =.28). CONCLUSIONS: Our serologic study confirms the higher prevalence of HHV-8 antibodies in patients with KS and demonstrates that contrary to other human herpesviruses, HHV-8 is not a ubiquitous virus in France. We could not determine any causal association between HHV-8 and pemphigus or lymphoproliferative disorders of the skin.

Mutations in the human immunodeficiency virus type 1 reverse transcriptase gene observed in stavudine and didanosine strains obtained by in vitro passages.

We have selected a human immunodeficiency virus type 1 (HIV1) using the technique of in vitro selection to generate variants that are resistant to didanosine and/or stavudine. After serial passages of the Lai strain of HIV1 in MT-2 cells in increased concentrations of didanosine-stavudine association, 2 novel mutations in reverse transcriptase at codon 57 (Asp-->His) and at codon 98 (AIa-->Val) were observed. These mutations were associated with an 11.5-fold increase in the didanosine and a 4.5-fold increase in the stavudine 50% inhibitory concentration.

Yellow fever 5' noncoding region as a potential element to improve hepatitis C virus production through modification of translational control.

The lengthy 5' noncoding region (5' NCR) of hepatitis C virus (HCV) RNA forms a highly ordered secondary structure, very conserved among different strains. It includes an internal ribosome entry site (IRES) element, responsible for the cap-independent translation initiation of HCV RNA. Similarly to the IRES of hepatitis A virus (HAV), another human hepatitis virus, HCV IRES, activity in internal initiation of translation is weak. Furthermore, both viruses exhibit a poor growth phenotype that may result at least partially from an inhibitory control of translation. To enhance HCV translation, as a preliminary step in designing constructs for improvement in viral production, we sought to evaluate a chimeric construct containing the yellow fever virus (YFV) 5' NCR fused to the initiation codon of the HCV coding sequence. YF viral RNA, as the majority of eukaryotic messenger RNAs, is translated by a ribosome scanning mechanism in a cap-dependent manner. The efficiency of translation initiation of the parental HCV construct was compared in vitro in rabbit reticulocyte lysates with that of the chimeric construct containing YFV 5' NCR. Surprisingly, the related distanced YFV 5' NCR was fivefold more active than was the wild-type HCV IRES in directing that function. Furthermore, chimeric transcripts were shown to be effective in vivo after transfection of eukaryotic cells. Taken together, these results raise the following question: why has the HCV genus evolved to the acquisition of an IRES element within its 5' NCR among the Flaviviridae family?

Lack of evidence of human herpesvirus 8 DNA sequences in HIV-negative patients with various lymphoproliferative disorders of the skin.

Human herpesvirus 8 (HHV-8) is a new virus which has been reported in Kaposi's sarcoma and some lymphoproliferative disorders such as Castleman's disease and body-cavity-based lymphoma. Because HHV-8 shares homology with Epstein-Barr virus (EBV), we searched for the presence of HHV-8 DNA sequences in various cutaneous T- and B-cell lymphoma by the polymerase chain reaction (PCR). Forty-seven HIV-negative patients with cutaneous lymphoma or large plaque parapsoriasis were enrolled in the study. For the detection of HHV-8 DNA sequences we used PCR followed by a hybridization with a digoxigenin-labelled probe and nested-PCR. HHV-8 DNA sequences could only be detected in a patient with large plaque parapsoriasis. Our study does not suggest any direct implication of HHV-8 in the pathogenesis of most cutaneous lymphoma. Serological studies will be helpful to appreciate if there is an epidemiological link between HHV-8 and cutaneous lymphomas.

[The discovery of three novel human viruses, human herpesviruses 6, 7, and 8]. / La découverte de trois nouveaux virus humains, les herpèsvirus humains 6, 7 et 8.

Three novel human herpesviruses have been discovered in the last years: human herpesvirus 6 (HHV-6) in 1986, human herpesvirus 7 (HHV-7) in 1990, human herpesvirus 8 (HHV-8) in 1994. HHV-6 and HHV-7 were identified after their isolation from blood lymphocyte cultures, while HHV-8 was first detected by means of a specific molecular biology approach in the search for the etiologic agent of Kaposi's sarcoma. The three viruses infect lymphocytes, T-cells in the case of HHV-6 and HHV-7, B-cells in the case of HHV-8. Human infection with HHV-6 and HHV-7 is ubiquitous and widespread while HHV-8 infection seems to be more restricted, at least in Western countries. The propagation in cell culture in vitro can be done easily with HHV-6, with more difficulties in the case of HHV-7 and has not been completely obtained in the case of HHV-8. The polymerase chain reaction is the common method for the detection of these three viruses in human samples. The oncogenic role of HHV-6 and HHV-7 which were both classified in Betaherpesvirinae subfamily has not been convincingly demonstrated. HHV-8, classified as a member of Gammaherpesvirinae subfamily, is strongly associated with three lymphoproliferative diseases: Kaposi's sarcoma, Castleman's disease and primary effusion lymphomas.

Exacerbations of clinical symptoms in human immunodeficiency virus type 1-infected patients with multicentric Castleman's disease are associated with a high increase in Kaposi's sarcoma herpesvirus DNA load in peripheral blood mononuclear cells.

The epidemiologic link between multicentric Castleman's disease (MCD) and Kaposi's sarcoma (KS) and the high frequency of KS herpesvirus (KSHV) detection in both diseases raise the question of a role of this new virus in the pathogenesis of MCD. To explore this hypothesis, the KSHV DNA load was investigated in peripheral blood mononuclear cells of 3 human immunodeficiency virus (HIV)-infected patients with MCD at different points during the clinical course. Clinical parameters, such as fever and the presence of lymphadenopathy, were systematically assessed. Hemogram and C-reactive protein level determinations were performed as standard procedures. KSHV DNA load was investigated by means of semiquantitative polymerase chain reaction assay using peripheral blood mononuclear cells of the patients. A correlation between the variation in clinical and biologic parameters related to MCD and KSHV DNA load was found, suggesting a close relationship between KSHV and MCD in HIV-1-infected patients.