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Showing papers on "Viremia published in 2005"


Journal ArticleDOI
TL;DR: Whether intensive monitoring and discontinuation of mycophenolate (MMF) or azathioprine (AZA), upon detection of BK viremia, could prevent BK nephropathy with tacrolimus (FK506) versus cyclosporine (CyA) is investigated.

630 citations


Journal ArticleDOI
TL;DR: Two distinct mechanisms of sequence evolution involved in HCV persistence are revealed: viral escape from CD8+ T cell responses and optimization of replicative capacity.
Abstract: Hepatitis C virus (HCV) infection frequently persists despite substantial virus-specific cellular immune responses. To determine if immunologically driven sequence variation occurs with HCV persistence, we coordinately analyzed sequence evolution and CD8+ T cell responses to epitopes covering the entire HCV polyprotein in subjects who were followed prospectively from before infection to beyond the first year. There were no substitutions in T cell epitopes for a year after infection in a subject who cleared viremia. In contrast, in subjects with persistent viremia and detectable T cell responses, we observed substitutions in 69% of T cell epitopes, and every subject had a substitution in at least one epitope. In addition, amino acid substitutions occurred 13-fold more often within than outside T cell epitopes (P < 0.001, range 5–38). T lymphocyte recognition of 8 of 10 mutant peptides was markedly reduced compared with the initial sequence, indicating viral escape. Of 16 nonenvelope substitutions that occurred outside of known T cell epitopes, 8 represented conversion to consensus (P = 0.015). These findings reveal two distinct mechanisms of sequence evolution involved in HCV persistence: viral escape from CD8+ T cell responses and optimization of replicative capacity.

311 citations


Journal ArticleDOI
TL;DR: Using a sensitive neutralization assay based on infectious HCV pseudoparticles, the kinetics of humoral responses in a cohort of acute-phase patients infected during a single nosocomial outbreak in a hemodialysis center are studied to provide new insights into the mechanisms of viral persistence and immune control of viremia.
Abstract: The factors leading to spontaneous clearance of hepatitis C virus (HCV) or to viral persistence are elusive. Understanding virus-host interactions that enable acute HCV clearance is key to the development of more effective therapeutic and prophylactic strategies. Here, using a sensitive neutralization assay based on infectious HCV pseudoparticles (HCVpp), we have studied the kinetics of humoral responses in a cohort of acute-phase patients infected during a single nosocomial outbreak in a hemodialysis center. The 17 patients were monitored for the spontaneous outcome of HCV infection for 6 months before a treatment decision was made. Blood samples were taken frequently (15 ± 4 per patient). Phylogenetic analysis of the predominant virus(es) revealed infection by only one of two genotype 1b strains. While all patients seroconverted, their sera induced two opposing effects in HCVpp infection assays: inhibition and facilitation. Furthermore, the ability of sera to facilitate or inhibit infection correlated with the presence of either infecting HCV strain and divided the patients into two groups. In group 1, the progressive emergence of a relatively strong neutralizing response correlated with a fluctuating decrease in high initial viremia, leading to control of viral replication. Patients in group 2 failed to reduce viremia within the acute phase, and no neutralizing responses were detected despite seroconversion. Strikingly, sera of group 2, as well as naive sera, facilitated infection by HCVpp displaying HCV glycoproteins from different genotypes and strains, including those retrieved from patients. These results provide new insights into the mechanisms of viral persistence and immune control of viremia.

289 citations


Journal ArticleDOI
TL;DR: It is shown that a prime/boost AIDS vaccine approach elicits potent ADCC activity correlating with protection against SIV in rhesus macaques (Macacca mulatta), and this exposure exposesADCC activity as an immune correlate that may be relevant in the rational design of an efficacious vaccine against HIV.
Abstract: Effector cells armed with Abs can eliminate virus-infected target cells by Ab-dependent cellular cytotoxicity (ADCC), an immune mechanism that has been largely overlooked in HIV vaccine development. Here, we show that a prime/boost AIDS vaccine approach elicits potent ADCC activity correlating with protection against SIV in rhesus macaques (Macacca mulatta). Priming with replicating adenovirus type 5 host range mutant-SIV recombinants, followed by boosting with SIV gp120, elicited Abs with ADCC activity against SIV(mac251)-infected cells. In vitro ADCC activity correlated with in vivo reduced acute viremia after a mucosal challenge with pathogenic SIV. Our findings expose ADCC activity as an immune correlate that may be relevant in the rational design of an efficacious vaccine against HIV.

287 citations


Journal ArticleDOI
TL;DR: In most individuals, the CD8+ T cell responses generated early in HCV infection decline in peripheral blood and are not replaced with new responses.

240 citations


Journal ArticleDOI
TL;DR: The data underscore the importance of nucleic acid screening of blood donations to prevent HCV transmission and of long-term follow-up to ascertain whether there is viral persistence, at least among injection drug users.
Abstract: Background More than two-thirds of hepatitis C virus (HCV) infections in Western countries are caused by injection drug use, but prospective clinical data regarding the most common mode of HCV acquisition are rare, in part because acute-phase HCV infection is usually asymptomatic. Methods To characterize acute-phase HCV infection, 179 HCV antibody-negative injection drug users were prospectively evaluated; 62 (34%) of these patients had seroconverted. Twenty of the participants who seroconverted had long-term follow-up with consistent monthly sampling before and after seroconversion, allowing detailed study. Results The first indication of HCV infection was the presence of HCV RNA in serum, which preceded elevation of alanine transaminase levels and total bilirubin levels to > or =2 times baseline in 45% and 77% of patients, respectively. No subjects had jaundice. The median time from initial viremia to seroconversion was 36 days (range, 32-46 days). In one instance, viremia was detected 434 days before seroconversion. However, in no other case was HCV RNA detected >63 days before seroconversion. In subjects with viral persistence, a stable level of HCV RNA in the blood was noted in some subjects within 60 days after the initial detection of viremia, but in others, it was not apparent until >1 year later. In subjects with long-term viral clearance, HCV became persistently undetectable as early as 94 and as late as 620 days after initial viremia. Conclusions These data underscore the importance of nucleic acid screening of blood donations to prevent HCV transmission and of long-term follow-up to ascertain whether there is viral persistence, at least among injection drug users.

226 citations


Journal ArticleDOI
TL;DR: Control of HIV replication is associated with high levels of HIV-specific IL-2+ and IFN-γ+ CD4+ T cells and low levels of T-cell activation, suggesting that functional immunity can be reconstituted with partially suppressive highly active antiretroviral therapy.
Abstract: The human immunodeficiency virus (HIV)-mediated immune response may be beneficial or harmful, depending on the balance between expansion of HIV-specific T cells and the level of generalized immune activation. The current study utilizes multicolor cytokine flow cytometry to study HIV-specific T cells and T-cell activation in 179 chronically infected individuals at various stages of HIV disease, including those with low-level viremia in the absence of therapy (“controllers”), low-level drug-resistant viremia in the presence of therapy (partial controllers on antiretroviral therapy [PCAT]), and high-level viremia (“noncontrollers”). Compared to noncontrollers, controllers exhibited higher frequencies of HIV-specific interleukin-2-positive gamma interferon-positive (IL-2+ IFN-γ+) CD4+ T cells. The presence of HIV-specific CD4+ IL-2+ T cells was associated with low levels of proliferating T cells within the less-differentiated T-cell subpopulations (defined by CD45RA, CCR7, CD27, and CD28). Despite prior history of progressive disease, PCAT patients exhibited many immunologic characteristics seen in controllers, including high frequencies of IL-2+ IFN-γ+ CD4+ T cells. Measures of immune activation were lower in all CD8+ T-cell subsets in controllers and PCAT compared to noncontrollers. Thus, control of HIV replication is associated with high levels of HIV-specific IL-2+ and IFN-γ+ CD4+ T cells and low levels of T-cell activation. This immunologic state is one where the host responds to HIV by expanding but not exhausting HIV-specific T cells while maintaining a relatively quiescent immune system. Despite a history of advanced HIV disease, a subset of individuals with multidrug-resistant HIV exhibit an immunologic profile comparable to that of controllers, suggesting that functional immunity can be reconstituted with partially suppressive highly active antiretroviral therapy.

215 citations


Journal ArticleDOI
TL;DR: It is important to characterize viral dynamics in early hepatitis C virus (HCV) infection to further the understanding of viral pathogenesis and the potential for secondary transmission in acute infection through blood transfusion or other routes.

195 citations


Journal ArticleDOI
TL;DR: It is demonstrated that predominant CD4+ T cell epitopes in persons with resolved HCV infection are preferentially located in the nonstructural proteins and are immunogenic in the context of multiple class II molecules.
Abstract: A vigorous hepatitis C virus (HCV)-specific Th cell response is regarded as essential to the immunological control of HCV viremia. The aim of this study was to comprehensively define the breadth and specificity of dominant HCV-specific CD4(+) T cell epitopes in large cohorts of subjects with chronic and spontaneously resolved HCV viremia. Following in vitro stimulation of PBMC, HCV-specific cell cultures from each subject were screened with an overlapping panel of synthetic 20-mer peptides spanning the entire HCV polyprotein. Of 22 subjects who spontaneously controlled HCV viremia, all recognized at least one of a group of six epitopes situated within the nonstructural (NS) proteins NS3, NS4, and NS5, each of which was detected by >30% of subjects, but most subjects recognized additional, more heterogeneous specificities. In contrast, none of the most frequently targeted epitopes was detected by >5% of persons with chronic infection. The most frequently recognized peptides showed promiscuous binding to multiple HLA-DR molecules in in vitro binding assays and were restricted by different HLA-DR molecules in functional assays in different persons. These data demonstrate that predominant CD4(+) T cell epitopes in persons with resolved HCV infection are preferentially located in the nonstructural proteins and are immunogenic in the context of multiple class II molecules. This comprehensive characterization of CD4(+) T cell epitopes in resolved HCV infection provides important information to facilitate studies of immunopathogenesis and HCV vaccine design and evaluation.

187 citations


Journal ArticleDOI
01 Aug 2005-Blood
TL;DR: BK virus seems to play a role in the development of HC and quantitative detection of BK DNA in plasma appears to be a marker of Bk virus disease in HCT recipients.

151 citations


Journal ArticleDOI
TL;DR: Lymphocyte reconstitution appears to play a crucial role in clearance of HAdV viremia and survival of the host, warranting further development of therapeutic interventions aimed at improving immune recovery.
Abstract: Background. Human adenovirus (HAdV) infections are increasingly frequent complications of allogeneic stem-cell transplantation (SCT), especially in children. Only a few data on the correlation between immune recovery and the course of HAdV infection are available, and data on HAdV-specific responses are lacking. Methods. In a prospective study, we determined the correlation between the HAdV DNA load in plasma and lymphocyte reconstitution in 48 children after allogeneic SCT. Additionally, HAdV-specific humoral and cellular immune responses were investigated. Results. HAdV infection occurred in 21 patients (44%), and, in 6 of these patients, the infection progressed to viremia, as demonstrated by the presence of HAdV DNA in plasma. Low lymphocyte counts at the onset of infection were predictive of HAdV viremia. Survival of patients with HAdV viremia was associated with an increase in lymphocyte counts during the first weeks after infection. In these patients, HAdV-specific CD4 + T cell responses, as well as increases in titers of neutralizing antibody, were detected after clearance of HAdV DNA from plasma. Conclusions. Lymphocyte reconstitution appears to play a crucial role in clearance of HAdV viremia and survival of the host, warranting further development of therapeutic interventions aimed at improving immune recovery.

Journal ArticleDOI
TL;DR: This mouse model of HBV infection is a useful tool for the study ofHBV virology and evaluation of anti‐HBV drugs and results indicate that HBeAg is dispensable for active viral production and transmission.

Journal ArticleDOI
TL;DR: It is discovered that the order of hA3G mRNA levels is LTNPs > HIV-uninfected subjects > progressors, which indicates that the protection against HIV disease progression in humans is limited to long-term nonprogressors and progressors.
Abstract: APOBEC3G/CEM15 (hA3G) is a novel host factor that confers resistance to lentiviral infection under experimental conditions. Human immunodeficiency virus (HIV) type 1, however, produces viral infectivity factor (Vif) that targets hA3G for proteolysis, thereby escaping this defense system. To examine hA3G's contribution to the protection against HIV disease progression in humans, we quantified hA3G mRNA levels in peripheral blood mononuclear cells from 6 HIV-uninfected and 25 HIV-infected subjects; the latter group included 8 long-term nonprogressors (LTNPs) and 17 progressors. None of the HIV-infected subjects were receiving antiretroviral therapy. We found a striking inverse correlation between hA3G mRNA levels and HIV viral loads (P ≤ 0.00009) and a highly significant positive correlation between hA3G mRNA levels and CD4 cell counts (P ≤ 0.00012) in these patients. Furthermore, we discovered that the order of hA3G mRNA levels is LTNPs > HIV-uninfected subjects > progressors.

Journal ArticleDOI
TL;DR: The partial control of postchallenge viremia after CD8+ lymphocyte depletion suggests that both humoral and cellular immune responses induced by live attenuated SIV vaccines can contribute to protection against a pathogenic challenge and that the relative contribution of each of these responses to protection may be genetically determined.
Abstract: Although live attenuated vaccines can provide potent protection against simian immunodeficiency virus (SIV) and simian-human immunodeficiency virus challenges, the specific immune responses that confer this protection have not been determined To test whether cellular immune responses mediated by CD8+ lymphocytes contribute to this vaccine-induced protection, we depleted rhesus macaques vaccinated with the live attenuated virus SIVmac239Δ3 of CD8+ lymphocytes and then challenged them with SIVmac251 by the intravenous route While vaccination did not prevent infection with the pathogenic challenge virus, the postchallenge levels of virus in the plasmas of vaccinated control animals were significantly lower than those for unvaccinated animals The depletion of CD8+ lymphocytes at the time of challenge resulted in virus levels in the plasma that were intermediate between those of the vaccinated and unvaccinated controls, suggesting that CD8+ cell-mediated immune responses contributed to protection Interestingly, at the time of challenge, animals expressing the Mamu-A*01 major histocompatibility complex class I allele showed significantly higher frequencies of SIV-specific CD8+ T-cell responses and lower neutralizing antibody titers than those in Mamu-A*01− animals Consistent with these findings, the depletion of CD8+ lymphocytes abrogated vaccine-induced protection, as judged by the peak postchallenge viremia, to a greater extent in Mamu-A*01+ than in Mamu-A*01− animals The partial control of postchallenge viremia after CD8+ lymphocyte depletion suggests that both humoral and cellular immune responses induced by live attenuated SIV vaccines can contribute to protection against a pathogenic challenge and that the relative contribution of each of these responses to protection may be genetically determined

Journal ArticleDOI
TL;DR: It is demonstrated that during acquisition of drug resistance, wild-type episomal cDNAs are replaced by M184V-harboring episomes, which indicates that evolution of episomal viral c DNAs is a valid surrogate of ongoing viral replication in HIV-1-infected individuals.
Abstract: Current regimens for the management of human immunodeficiency virus type 1 (HIV-1) infection suppress plasma viremia to below detectable levels for prolonged intervals. Nevertheless, there is a rapid resumption in plasma viremia if therapy is interrupted. Attempts to characterize the extent of viral replication under conditions of potent suppression and undetectable plasma viremia have been hampered by a lack of convenient assays that can distinguish latent from ongoing viral replication. Using episomal viral cDNA as a surrogate for ongoing replication, we previously presented evidence that viral replication persists in the majority of infected individuals with a sustained aviremic status. The labile nature of viral episomes and hence their validity as surrogate markers of ongoing replication in individuals with long-term-suppressed HIV-1 infection have been analyzed in short-term in vitro experiments with conflicting results. Since these in vitro experiments do not shed light on the long-term in vivo dynamics of episomal cDNA or recapitulate the natural targets of infection in vivo, we have analyzed the dynamics of episomal cDNA turnover in vivo by following the emergence of an M184V polymorphism in plasma viral RNA, in episomal cDNA, and in proviral DNA in patients on suboptimal therapies. We demonstrate that during acquisition of drug resistance, wild-type episomal cDNAs are replaced by M184V-harboring episomes. Importantly, a complete replacement of wild-type episomes with M184V-containing episomes occurred while proviruses remained wild type. This indicates that episomal cDNAs are turned over by degradation rather than through death or tissue redistribution of the infected cell itself. Therefore, evolution of episomal viral cDNAs is a valid surrogate of ongoing viral replication in HIV-1-infected individuals.

Journal ArticleDOI
TL;DR: Nonviremic transmission of WNV between cofeeding mosquitoes is demonstrated and the status of dead-end hosts in the WNV transmission cycle is questioned, which may partly explain the success with which WNV established and rapidly dispersed throughout North America.
Abstract: West Nile virus (WNV) is now the predominant circulating arthropod-borne virus in the United States with >15,000 human cases and >600 fatalities since 1999. Conventionally, mosquitoes become infected when feeding on viremic birds and subsequently transmit the virus to susceptible hosts. Here, we demonstrate nonviremic transmission of WNV between cofeeding mosquitoes. Donor, Culex pipiens quinquefasciatus mosquitoes infected with WNV were fed simultaneously with uninfected “recipient” mosquitoes on naive mice. At all times, donor and recipient mosquitoes were housed in separate sealed containers, precluding the possibility of mixing. Recipients became infected in all five trials, with infection rates as high as 5.8% and no detectable viremia in the hosts. Remarkably, a 2.3% infection rate was observed when 87 uninfected mosquitoes fed adjacent to a single infected mosquito. This phenomenon could potentially enhance virus survival, transmission, and dispersion and obviate the requirement for viremia. All vertebrates, including immune and insusceptible animals, might therefore facilitate mosquito infection. Our findings question the status of dead-end hosts in the WNV transmission cycle and may partly explain the success with which WNV established and rapidly dispersed throughout North America.

Journal ArticleDOI
TL;DR: It is shown that 30–90% of circulating naïve cells were productively infected by day 10 after inoculation, which implies that direct cell killing, not bystander apoptosis, is responsible for the massive loss of CD4+ T cells in the X4-tropic SHIV model.
Abstract: Unlike HIV-1 and simian immunodeficiency virus (SIV), which induce a slow, unrelenting loss of immune function spanning several years, highly pathogenic simian–human immunodeficiency viruses (SHIVs) induce a rapid, complete, and irreversible depletion of CD4+ T lymphocytes in rhesus monkeys within weeks of infection, leading to death from immunodeficiency. We recently reported that, because these SHIVs exclusively use the CXCR4 coreceptor for cell entry, they target naive CD4+ T cells for depletion in infected monkeys, whereas SIVs, which use CCR5, not CXCR4, cause the selective loss of memory CD4+ T lymphocytes in vivo. Here we show both by DNA PCR analyses and infectivity assays, using live sorted CD4+ T lymphocyte subsets, that 30–90% of circulating naive cells were productively infected by day 10 after inoculation. This result implies that direct cell killing, not bystander apoptosis, is responsible for the massive loss of CD4+ T cells in the X4-tropic SHIV model. Furthermore, we directly demonstrate that >96% of virus producing cells did not express the Ki-67 proliferation marker on day 10 after inoculation using confocal microscopic analysis of lymph nodes samples. This finding is consistent with the prodigious levels of plasma viremia measured during acute X4-tropic SHIV infections of macaques being generated almost entirely by resting naive CD4+ T cells.

Journal ArticleDOI
TL;DR: In children with symptomatic congenital CMV infection involving the CNS, viremia during early infancy is associated with hearing loss and systemic CMV disease.
Abstract: Objective The study sought to determine the relationship between cytomegalovirus (CMV) viremia during early infancy and clinical and laboratory outcome events, particularly hearing loss in infants with symptomatic congenital CMV infection involving the central nervous system (CNS). Study design A total of 147 infant patients were enrolled prospectively in 2 clinical trials evaluating ganciclovir for the treatment of symptomatic congenital CMV infection involving the CNS. Aliquots of serum collected at enrollment in either of the 2 trials were available from 50 of the infants, and the degree of viremia was determined by real-time quantitative polymerase chain reaction. Results Of the 50 infants from whom serum samples were available, 37 had detectable CMV DNA in the serum sample collected at enrollment and were classified as viremic. Viremic infants were more likely to have (1) hearing loss both at enrollment (P = .045) and at the 6-month follow-up testing (P = .035) and (2) other indicators of active CMV disease, including elevated levels of alanine aminotransferase, petechial rash, and organomegaly. Conclusion In children with symptomatic congenital CMV infection involving the CNS, viremia during early infancy is associated with hearing loss and systemic CMV disease.

Journal ArticleDOI
TL;DR: Adenovirus viremia is relatively common in adult liver, kidney and heart transplant recipients and most infections are asymptomatic, transient and self‐limited.

Journal ArticleDOI
TL;DR: Assessment of the viral kinetics after acute infection showed that the virus is not rapidly cleared from healthy hosts, despite early resolution of symptoms, which challenges the current conception of the virus' pathogenesis.
Abstract: Parvovirus B19 is a common, clinically significant pathogen. Reassessment of the viral kinetics after acute infection showed that the virus is not rapidly cleared from healthy hosts, despite early resolution of symptoms. These findings challenge our current conception of the virus' pathogenesis and have implications for the management of the infection.

Journal ArticleDOI
TL;DR: In each of seven patients studied, antibodies capable of CMI appeared at or shortly after the peak in viremia, concomitantly with detection of virus-specific T-cell responses.
Abstract: Specific CD8 T-cell responses to human immunodeficiency virus type 1 (HIV-1) are induced in primary infection and make an important contribution to the control of early viral replication. The importance of neutralizing antibodies in containing primary viremia is questioned because they usually arise much later. Nevertheless antienvelope antibodies develop simultaneously with, or even before, peak viremia. We determined whether such antibodies might control viremia by complement-mediated inactivation (CMI). In each of seven patients studied, antibodies capable of CMI appeared at or shortly after the peak in viremia, concomitantly with detection of virus-specific T-cell responses. The CMI was effective on both autologous and heterologous HIV-1 isolates. Activation of the classical pathway and direct viral lysis were at least partly responsible. Since immunoglobulin G (IgG)-antibodies triggered the CMI, specific memory B cells could also be induced by vaccination. Thus, consideration should be given to vaccination strategies that induce IgG antibodies capable of CMI.

Journal ArticleDOI
TL;DR: It is shown that oral delivery of CMPD167, a small molecule that binds to the CCR5 coreceptor, for 10–14 d can protect a substantial proportion of macaques from vaginal infection with a C CR5-using virus (SHIV-162P3).
Abstract: Pre-exposure oral prophylaxis with antiviral drugs is a potential method for preventing transmission of human immunodeficiency virus type 1 (HIV-1). We show that oral delivery of CMPD167, a small molecule that binds to the CCR5 coreceptor, for 10-14 d can protect a substantial proportion of macaques from vaginal infection with a CCR5-using virus (SHIV-162P3). The macaques that became infected despite receiving CMPD167 had reduced plasma viremia levels during the earliest stages of infection.

Journal ArticleDOI
TL;DR: The data show that the combinations of DNA vaccines producing native and modified forms of antigens elicit more balanced immune responses able to significantly reduce viremia for a long period (8 months) following pathogenic challenge with SIVmac251.
Abstract: We have tested the efficacy of DNA immunization as a single vaccination modality for rhesus macaques followed by highly pathogenic SIVmac251 challenge. To further improve immunogenicity of the native proteins, we generated expression vectors producing fusion of the proteins Gag and Env to the secreted chemokine MCP3, targeting the viral proteins to the secretory pathway and to a beta-catenin (CATE) peptide, targeting the viral proteins to the intracellular degradation pathway. Macaques immunized with vectors expressing the MCP3-tagged fusion proteins developed stronger antibody responses. Following mucosal challenge with pathogenic SIVmac251, the vaccinated animals showed a statistically significant decrease in viral load (P = 0.010). Interestingly, macaques immunized with a combination of vectors expressing three forms of antigens (native protein and MCP3 and CATE fusion proteins) showed the strongest decrease in viral load (P = 0.0059). Postchallenge enzyme-linked immunospot values for Gag and Env as well as gag-specific T-helper responses correlated with control of viremia. Our data show that the combinations of DNA vaccines producing native and modified forms of antigens elicit more balanced immune responses able to significantly reduce viremia for a long period (8 months) following pathogenic challenge with SIVmac251.

Journal ArticleDOI
TL;DR: The results indicate that the rPRV-GP5 is safe for vaccinates and able to confer significant protection against clinical disease and reduce pathogenic lesions induced by PRRSV challenge in vaccinated pigs.

Journal ArticleDOI
TL;DR: Viremia may occur during RV respiratory infections in normal children and is rather common in the early course of acute asthma exacerbations, suggesting that rhinoviremia might be involved in asthma exacerbation pathogenesis.
Abstract: Rationale: Viremia has been implicated in many viral infections; however, viremia due to rhinovirus (RV; rhinoviremia) has been considered not to occur in normal individuals.Objective: To evaluate whether RV enters the bloodstream and identify the possible risk factors.Methods: Nasopharyngeal washes (NPWs) of 221 children with respiratory infections were examined for the presence of RV by reverse transcription–polymerase chain reaction. Blood from 88 children, whose NPW was RV-positive, and 31 of RV-negative control subjects was subsequently examined for the presence of RV in the blood by semi-nested reverse transcription–polymerase chain reaction. Rhinoviremia was then correlated with clinical characteristics of the disease.Results: RV was detected in the blood of 10 out of 88 NPW RV-positive cases (11.4%): 7 of 28 children with asthma exacerbations (25.0%), 2 of 26 with common cold (7.7%), 1 of 25 with bronchiolitis (4.0%), and 0 of 9 with pneumonia (0%). All NPW RV-negative cases were negative in the b...

Journal ArticleDOI
TL;DR: JCV viral loads were surprisingly high in all patient categories studied, but did not result in viremia or viral nephropathy, although both BKV and JCV are widely latent in patients accepted for transplantation, concurrent reactivation of both viruses was infrequent.
Abstract: JC virus (JCV) rarely causes kidney disease, whereas BK virus (BKV) is a known cause of viral nephropathy. Existing studies on prevalence of JCV in healthy and transplanted subjects have reported only qualitative detection of viral DNA. We used quantitative PCR (qPCR) to assess JC viral load in transplant recipients and non-immunosuppressed controls, and compared JCV loads to BKV loads. JC viruria was seen in 8/23 (34.7%) controls, 23/103 (22.3%) renal, and 10/44 (22.7%) liver transplant patients. No patient developed JC viremia. BK viruria was seen in 2/23 (8.7%) controls, 36/103 (34.9%) renal, and 7/44 (15.9%) liver transplant patients. BK viremia was seen only in the kidney (8/103 = 7.7%) patients. The mean BKV urinary load was higher in kidney compared to liver patients and controls (4.22E + 07 vs. 2.88E + 05 vs. 4.39E + 02 copies/ml), whereas JC viral load was similar for all three patient groups (1.55E + 06 vs. 2.66E + 06 vs. 2.13E + 06 copies/ml). JCV viral loads were surprisingly high in all patient categories studied, but did not result in viremia or viral nephropathy. Although both BKV and JCV are widely latent in patients accepted for transplantation, concurrent reactivation of both viruses was infrequent. BKV viremia was seen in kidney but not liver recipients. The mechanisms underlying these notable phenomena remain to be investigated.

Journal ArticleDOI
01 Aug 2005-Virology
TL;DR: Testing the feasibility of BALB/c mice as an experimental model in the study of dengue disease revealed liver injury with viral antigens detection, and data correlate to the development of the disease described in humans.

Journal ArticleDOI
TL;DR: This study provides new evidence that virulent HRV causes transient viremia and upper respiratory tract infection in addition to gastrointestinal infection in gnotobiotic pigs, confirming previous reports of rotavirus antigenemia and suggesting that intestinal infection might be initiated from the basolateral side of the epithelial cells via viresmia.
Abstract: Respiratory symptoms with rotavirus shedding in nasopharyngeal secretions have been reported in children with and without gastrointestinal symptoms (Zheng et al., 1991, J. Med. Virol. 34:29-37). To investigate if attenuated and virulent human rotavirus (HRV) strains cause upper respiratory tract infections or viremia in gnotobiotic pigs, we inoculated them with attenuated or virulent HRV intranasally, intravenously, or orally or via feeding tube (gavage) and assayed virus shedding. After oral or intranasal inoculation with attenuated HRV, the pigs remained asymptomatic, but 79 to 95% shed virus nasally and 5 to 17% shed virus rectally. After inoculation by gavage, no pigs shed virus nasally or rectally, but all pigs seroconverted with antibodies to HRV. No viremia was detected through postinoculation day 10. Controls inoculated intranasally with nonreplicating rotavirus-like particles or mock inoculated did not shed virus. In contrast, 100% of pigs inoculated with virulent HRV (oral, intranasal, or gavage) developed diarrhea, shed virus nasally and rectally, and had viremia. The infectivity of sera from the viremic virulent HRV-inoculated pigs was confirmed by inoculating gnotobiotic pigs orally with pooled HRV-positive serum. Serum-inoculated pigs developed diarrhea and fecal and nasal virus shedding and seroconverted with serum and intestinal HRV antibodies. Pigs inoculated intravenously with serum or intestinal contents from the viremic virulent HRV-inoculated pigs developed diarrhea, virus shedding, and viremia, similar to the orally inoculated pigs. This study provides new evidence that virulent HRV causes transient viremia and upper respiratory tract infection in addition to gastrointestinal infection in gnotobiotic pigs, confirming previous reports of rotavirus antigenemia (Blutt et al., Lancet 362:1445-1449, 2003). Our data also suggest that intestinal infection might be initiated from the basolateral side of the epithelial cells via viremia. Additionally, virus shedding patterns indicate a different pathogenesis for attenuated versus virulent HRV.

Journal ArticleDOI
TL;DR: It is demonstrated that IVIG treatment of parvovirus B19‐triggered anemia in transplant recipients offers an opportunity to resolve symptoms, but does not guarantee eradication of the virus.
Abstract: Organ transplant recipients infected with parvovirus B19 frequently develop persistent viremia associated with chronic anemia and pure red cell aplasia. In this study, a male renal transplant recipient who had been infected with parvovirus B19/genotype 2 after renal transplantation at the age of 34 years is described. The patient was repeatedly treated with high dose intravenous immunoglobulin (IVIG) that resulted in the resolvement of symptoms but not in virus eradication. During an observation period of 33 months after transplantation three phases associated with high parvovirus B19 viremia were observed. Both the first and the second viremic phases were combined with severe anemia. Parvovirus B19 specific IgM-antibodies were initially detected at the beginning of the second phase in continually rising concentrations. Initially eradication of the virus by immunoglobulin therapy was reported after the first viremic phase [Liefeldt et al. (2002): Nephrol Dial Transplant 17:1840-1842]. Retrospectively this statement has to be corrected. It was based on the use of a qualitative PCR assay specific for parvovirus B19 genotype 1 associated with reduced sensitivity for detection of genotype 2. After sequence analysis of the viral DNA and adjustment of a real-time PCR assay (TaqMan) for quantitative detection of all three B19 virus genotypes analysis of consecutive serum samples allowed the demonstration of long lasting phases with reduced viral loads following IVIG-treatment. These results demonstrate that IVIG treatment of parvovirus B19-triggered anemia in transplant recipients offers an opportunity to resolve symptoms, but does not guarantee eradication of the virus. Since reactivation of parvovirus B19 infection can result in high virus load associated with the recurrence of symptoms repeated screening for viral DNA is recommended using the TaqMan system established for quantitative detection of all three genotypes of parvovirus B19.

Journal ArticleDOI
TL;DR: It is shown that viral blips with realistic duration and amplitude can be generated by intercurrent infections in HAART treated patients and is proposed here that transient activation of the immune system by opportunistic infection may explain these episodes of viremia.