Showing papers on "Viremia published in 2014"
TL;DR: It is demonstrated that the viral reservoir is seeded rapidly after intrarectal SIV infection of rhesus monkeys, during the ‘eclipse’ phase, and before detectable viraemia, which raises important new challenges for HIV-1 eradication strategies.
Abstract: The viral reservoir represents a critical challenge for human immunodeficiency virus type 1 (HIV-1) eradication strategies. However, it remains unclear when and where the viral reservoir is seeded during acute infection and the extent to which it is susceptible to early antiretroviral therapy (ART). Here we show that the viral reservoir is seeded rapidly after mucosal simian immunodeficiency virus (SIV) infection of rhesus monkeys and before systemic viraemia. We initiated suppressive ART in groups of monkeys on days 3, 7, 10 and 14 after intrarectal SIVMAC251 infection. Treatment with ART on day 3 blocked the emergence of viral RNA and proviral DNA in peripheral blood and also substantially reduced levels of proviral DNA in lymph nodes and gastrointestinal mucosa as compared with treatment at later time points. In addition, treatment on day 3 abrogated the induction of SIV-specific humoral and cellular immune responses. Nevertheless, after discontinuation of ART following 24 weeks of fully suppressive therapy, virus rebounded in all animals, although the monkeys that were treated on day 3 exhibited a delayed viral rebound as compared with those treated on days 7, 10 and 14. The time to viral rebound correlated with total viraemia during acute infection and with proviral DNA at the time of ART discontinuation. These data demonstrate that the viral reservoir is seeded rapidly after intrarectal SIV infection of rhesus monkeys, during the 'eclipse' phase, and before detectable viraemia. This strikingly early seeding of the refractory viral reservoir raises important new challenges for HIV-1 eradication strategies.
519 citations
TL;DR: It is hypothesized that reactivation of latent viruses occurred with prolonged sepsis thereby providing evidence of clinically-relevant immunosuppression and potentially providing a means to serially-monitor patients' immune status and if viral loads are markedly elevated, they may contribute to morbidity and mortality.
Abstract: A current controversy is whether patients with sepsis progress to an immunosuppressed state. We hypothesized that reactivation of latent viruses occurred with prolonged sepsis thereby providing evidence of clinically-relevant immunosuppression and potentially providing a means to serially-monitor patients’ immune status. Secondly, if viral loads are markedly elevated, they may contribute to morbidity and mortality. This study determined if reactivation of herpesviruses, polyomaviruses, and the anellovirus TTV occurred in sepsis and correlated with severity. Serial whole blood and plasma samples from 560 critically-ill septic, 161 critically-ill non-septic, and 164 healthy age-matched patients were analyzed by quantitative-polymerase-chain-reaction for cytomegalovirus (CMV), Epstein-Barr (EBV), herpes-simplex (HSV), human herpes virus-6 (HHV-6), and TTV. Polyomaviruses BK and JC were quantitated in urine. Detectable virus was analyzed with respect to secondary fungal and opportunistic bacterial infections, ICU duration, severity of illness, and survival. Patients with protracted sepsis had markedly increased frequency of detectable virus. Cumulative viral DNA detection rates in blood were: CMV (24.2%), EBV (53.2%), HSV (14.1%), HHV-6 (10.4%), and TTV (77.5%). 42.7% of septic patients had presence of two or more viruses. The 50% detection rate for herpesviruses was 5–8 days after sepsis onset. A small subgroup of septic patients had markedly elevated viral loads (.10 4 –10 6 DNA copies/ml blood) for CMV, EBV, and HSV. Excluding TTV, DNAemia was uncommon in critically-ill non-septic patients and in age-matched healthy controls. Compared to septic patients without DNAemia, septic patients with viremia had increased fungal and opportunistic bacterial infections. Patients with detectable CMV in plasma had higher 90-day mortality compared to CMV-negative patients; p, 0.05. Reactivation of latent viruses is common with prolonged sepsis, with frequencies similar to those occurring in transplant patients on immunosuppressive therapy and consistent with development of an immunosuppressive state. Whether reactivated latent viruses contribute to morbidity and mortality in sepsis remains unknown.
293 citations
TL;DR: Novel associations between death, hemorrhage, and viremia were independently associated with elevated levels of several chemokines and cytokines and provided a better understanding of EHF pathophysiology and a starting point for researching new potential targets for therapeutic interventions.
Abstract: Background. Ebola hemorrhagic fever (EHF) outbreaks occur sporadically in Africa and result in high rates of death. The 2000–2001 outbreak of Sudan virus–associated EHF in the Gulu district of Uganda led to 425 cases, of which 216 were laboratory confirmed, making it the largest EHF outbreak on record. Serum specimens from this outbreak had been preserved in liquid nitrogen from the time of collection and were available for analysis. Methods. Available samples were tested using a series of multiplex assays to measure the concentrations of 55 biomarkers. The data were analyzed to identify statistically significant associations between the tested biomarkers and hemorrhagic manifestations, viremia, and/or death. Results. Death, hemorrhage, and viremia were independently associated with elevated levels of several chemokines and cytokines. Death and hemorrhagewere associated with elevated thrombomodulin and ferritin levels. Hemorrhage was also associated with elevated levels of soluble intracellular adhesion molecule. Viremia was independently associated with elevated levels of tissue factor and tissue plasminogen activator. Finally, samples from nonfatal cases had higher levels of sCD40L. Conclusions. These novel associations provide a better understanding of EHF pathophysiology and a starting point for researching new potential targets for therapeutic interventions.
181 citations
TL;DR: Strategies to prevent the occurrence of late-onset BKV-HC after allo-HSCT are urgently needed, especially in CBU and peripheral blood stem cell recipients.
Abstract: BK virus (BKV) reactivation has been increasingly associated with the occurrence of late-onset hemorrhagic cystitis (HC) after allogeneic hematopoietic SCT (allo-HSCT) resulting in morbidity and sometimes mortality. We investigated the incidence, risk factors and outcome of BKV-HC in 323 consecutive adult patients undergoing allo-HSCT over a 5-year period. BK viremia values for HC staging were evaluated, as well as the medico-economic impact of the complication. Forty-three patients developed BKV-HC. In univariate analysis, young age (P=0.028), unrelated donor (P=0.0178), stem cell source (P=0.0001), HLA mismatching (P=0.0022) and BU in conditioning regimen (P=0.01) were associated with a higher risk of developing BKV-HC. In multivariate analysis, patients receiving cord blood units (CBUs) (P=0.0005) and peripheral blood stem cells (P=0.011) represented high-risk subgroups for developing BKV-HC. BK viremia was directly correlated to HC severity (P=0.011) with a 3 to 6-log peak being likely associated with grades 3 or 4 HC. No correlation was found between BKV-HC and acute graft versus host disease or mortality rate. Patients with BKV-HC required a significantly longer duration of hospitalization (P<0.0001), more RBC (P=0.0003) and platelet transfusions (P<0.0001). Over the 5-year study period, the financial cost of the complication was evaluated at €2 376 076 ($3 088 899). Strategies to prevent the occurrence of late-onset BKV-HC after allo-HSCT are urgently needed, especially in CBU and peripheral blood stem cell recipients. BK viremia correlates with the severity of the disease. Prospective studies are required to test prophylactic approaches.
113 citations
TL;DR: It is uncertain whether LLV of <200 copies/ml confers independent risks, as this level of viremia may reflect assay-dependent artifacts or biologically meaningful events during suppression, and there is a dearth of clinical evidence to guide management when genotyping is not feasible.
Abstract: A goal of HIV therapy is to sustain suppression of the plasma viral load below the detection limits of clinical assays. However, widely followed treatment guidelines diverge in their interpretation and recommended management of persistent viremia of low magnitude, reflecting the limited evidence base for this common clinical finding. Here, we review the incidence, risk factors, and potential consequences of low-level HIV viremia (LLV; defined in this review as a viremia level of 50 to 500 copies/ml) and very-low-level viremia (VLLV; defined as a viremia level of <50 copies/ml detected by clinical assays that have quantification cutoffs of <50 copies/ml). Using this framework, we discuss practical issues related to the diagnosis and management of patients experiencing persistent LLV and VLLV. Compared to viral suppression at <50 or 40 copies/ml, persistent LLV is associated with increased risk of antiretroviral drug resistance and overt virologic failure. Higher immune activation and HIV transmission may be additional undesirable consequences in this population. It is uncertain whether LLV of <200 copies/ml confers independent risks, as this level of viremia may reflect assay-dependent artifacts or biologically meaningful events during suppression. Resistance genotyping should be considered in patients with persistent LLV when feasible, and treatment should be modified if resistance is detected. There is a dearth of clinical evidence to guide management when genotyping is not feasible. Increased availability of genotypic assays for samples with viral loads of <400 copies/ml is needed.
110 citations
TL;DR: AAV/HBV-infected mice may be used as a robust model for investigating the underlying mechanism(s) of HBV immunotolerance and for developing novel immunotherapies to eradicate HBV infections.
Abstract: Lack of an appropriate small animal model remains a major hurdle for studying the immunotolerance and immunopathogenesis induced by hepatitis B virus (HBV) infection. In this study, we report a mouse model with sustained HBV viremia after infection with a recombinant adeno-associated virus (AAV) carrying a replicable HBV genome (AAV/HBV). Similar to the clinical HBV carriers, the mice infected with AAV/HBV were sero-negative for antibodies against HBV surface antigen (HBsAg). Immunization with the conventional HBV vaccine in the presence of aluminum adjuvant failed to elicit an immune response against HBV in these mice. To identify a vaccine that can potentially circumvent this tolerance, the TLR9 agonist CpG was added to HBsAg as an adjuvant. Vaccination of mice with HBsAg/CpG induced not only clearance of viremia, but also strong antibody production and T-cell responses. Furthermore, both the DNA replication and protein expression of HBV were significantly reduced in the livers of AAV/HBV-infected mice. Accordingly, AAV/HBV-infected mice may be used as a robust model for investigating the underlying mechanism(s) of HBV immunotolerance and for developing novel immunotherapies to eradicate HBV infections.
99 citations
TL;DR: Improved single-copy assays with increased sensitivity are developed by improving nucleic acid recovery, designing qRT-PCR primers and a probe for a highly conserved region of integrase in the HIV-1 pol gene, and increasing the plasma volume tested (Mega-iSCA).
Abstract: A quantitative real-time PCR (qRT-PCR) assay with single-copy sensitivity targeting HIV-1 gag RNA (the gag single-copy assay [gSCA]) has been used widely to quantify plasma viremia below the limit of detection of clinical assays in patients on effective antiretroviral therapy (ART), but viral RNA in 15 to 30% of samples amplifies inefficiently because of primer/probe mismatches. We sought to develop improved single-copy assays with increased sensitivity by improving nucleic acid recovery, designing qRT-PCR primers and a probe for a highly conserved region of integrase in the HIV-1 pol gene (the integrase single-copy assay [iSCA]), and increasing the plasma volume tested (Mega-iSCA). We evaluated gSCA versus iSCA in paired plasma samples from 10 consecutive patients with viremia of >1,000 copies/ml and 25 consecutive patients on suppressive ART. Three of 10 viremic samples amplified inefficiently with gSCA compared to the Roche Cobas Ampliprep/TaqMan 2.0, whereas all 10 samples amplified efficiently with iSCA. Among 25 samples from patients on suppressive ART, 8 of 12 samples that were negative for HIV-1 RNA by gSCA had detectable HIV-1 RNA by iSCA, and iSCA detected 3-fold or higher HIV-1 RNA levels compared to gSCA in 10 of 25 samples. Large-volume plasma samples (>20 ml) from 7 patients were assayed using Mega-iSCA, and HIV-1 RNA was quantifiable in 6, including 4 of 5 that were negative by standard-volume iSCA. These improved assays with superior sensitivity will be useful for evaluating whether in vivo interventions can reduce plasma viremia and for assessing relationships between residual viremia and other virologic parameters, including the inducible proviral reservoir.
92 citations
TL;DR: Hepcidin induction is part of the pathogenically important systemic inflammatory cascade triggered during HIV-1 infection and may contribute to the establishment and maintenance of viral set-point, which is a strong predictor of progression to AIDS and death.
Abstract: During HIV type-1 (HIV-1), hepatitis C virus (HCV), and hepatitis B virus (HBV) infections, altered iron balance correlates with morbidity. The liver-produced hormone hepcidin dictates systemic iron homeostasis. We measured hepcidin, iron parameters, cytokines, and inflammatory markers in three cohorts: plasma donors who developed acute HIV-1, HBV, or HCV viremia during the course of donations; HIV-1-positive individuals progressing from early to chronic infection; and chronically HIV-1-infected individuals (receiving antiretroviral therapy or untreated). Hepcidin increased and plasma iron decreased during acute HIV-1 infection, as viremia was initially detected. In patients transitioning from early to chronic HIV-1 infection, hepcidin in the first 60 d of infection positively correlated with the later plasma viral load set-point. Hepcidin remained elevated in individuals with untreated chronic HIV-1 infection and in subjects on ART. In contrast to HIV-1, there was no evidence of hepcidin up-regulation or hypoferremia during the primary viremic phases of HCV or HBV infection; serum iron marginally increased during acute HBV infection. In conclusion, hepcidin induction is part of the pathogenically important systemic inflammatory cascade triggered during HIV-1 infection and may contribute to the establishment and maintenance of viral set-point, which is a strong predictor of progression to AIDS and death. However, distinct patterns of hepcidin and iron regulation occur during different viral infections that have particular tissue tropisms and elicit different systemic inflammatory responses. The hypoferremia of acute infection is therefore a pathogen-specific, not universal, phenomenon.
84 citations
TL;DR: In patients failing cART with LLV, HIV-1 genotyping provides reliable and reproducible results that are informative about emerging drug resistance.
Abstract: Background. We evaluated reliabilityand clinical usefulness of genotypic resistance testing (GRT) in patients for whom combination antiretroviral therapy (cART) was unsuccessful with viremia levels 50–1000 copies/mL, for whom GRT is generally not recommended by current guidelines. Methods. The genotyping success rate was evaluated in 12 828 human immunodeficiency virus type 1 (HIV-1) plasma samples with viremia >50 copies/mL, tested using the commercial ViroSeq HIV-1 Genotyping System or a homemade system. Phylogenetic analysis was performed to test the reliability and reproducibility of the GRT at lowlevel viremia (LLV). Drug resistance was evaluated in 3895 samples from 2200 patients for whom treatment was unsuccessful (viremia >50 copies/mL) by considering the resistance mutations paneled in the 2013 International Antiviral Society list. Results. Overall, the success rate of amplification/sequencing was 96.4%. Viremia levels of 50–200 and 201–500 copies/mL afforded success rates of 67.2% and 88.1%, respectively, reaching 93.2% at 501–1000 copies/mL and ≥97.3% above 1000 copies/mL. A high homology among sequences belonging to the same subject for 96.4% of patients analyzed was found. The overall resistance prevalence was 74%. Drug resistance was commonly found also at LLV. In particular, by stratifying for different viremia ranges, detection of resistance was as follows: 50–200 copies/ mL = 52.8%; 201–500 = 70%; 501–1000 = 74%; 1001–10 000 = 86.1%; 10 001–100 000 = 76.7%; and >100 000 = 63% (P< .001). Similar bell-shaped results were found when the GRT analysis was restricted to 2008–2012, although at a slightly lower prevalence. Conclusions. In patients failing cART with LLV, HIV-1 genotyping provides reliable and reproducible results that are informative about emerging drug resistance.
73 citations
TL;DR: It is demonstrated that a select number of HIV-specific monoclonal antibodies potently suppressed entry into CD4+ T cells of HIV isolated from the latent viral reservoir as well as replication of reservoir virus in autologous CD4- T cells derived from infected individuals receiving ART.
Abstract: Several highly potent and broadly neutralizing monoclonal antibodies against HIV have recently been isolated from B cells of infected individuals. However, the effects of these antibodies on the persistent viral reservoirs in HIV-infected individuals receiving antiretroviral therapy (ART) are unknown. We show that several HIV-specific monoclonal antibodies—in particular, PGT121, VRC01, and VRC03—potently inhibited entry into CD4+ T cells of HIV isolated from the latent viral reservoir of infected individuals whose plasma viremia was well controlled by ART. In addition, we demonstrate that HIV replication in autologous CD4+ T cells derived from infected individuals receiving ART was profoundly suppressed by three aforementioned and other HIV-specific monoclonal antibodies. These findings have implications for passive immunotherapy as an approach toward controlling plasma viral rebound in patients whose ART is withdrawn.
72 citations
TL;DR: The results suggest that, in HIV-infected VNPs, decreased infection of CD4+ TCM and TSCM, cells are involved in preservation ofCD4+ T cell homeostasis and lack of disease progression despite high viremia.
Abstract: A rare subset of HIV-infected individuals, designated viremic non-progressors (VNP), remain asymptomatic and maintain normal levels of CD4+ T-cells despite persistently high viremia. To identify mechanisms potentially responsible for the VNP phenotype, we compared VNPs (average >9 years of HIV infection) to HIV-infected individuals who have similar CD4+ T-cell counts and viral load, but who are likely to progress if left untreated (“putative progressors”, PP), thus avoiding the confounding effect of differences related to substantial CD4+ T cell depletion. We found that VNPs, compared to PPs, had preserved levels of CD4+ stem cell memory cells (TSCM (p<0.0001), which was associated with decreased HIV infection of these cells in VNPs (r = −0.649, p = 0.019). In addition, VNPs had decreased HIV infection in CD4+ central memory (TCM) cells (p = 0.035), and the total number of TCM cells was associated with increased proliferation of memory CD4+ T cells (r = 0.733, p = 0.01). Our results suggest that, in HIV-infected VNPs, decreased infection of CD4+ TCM and TSCM, cells are involved in preservation of CD4+ T cell homeostasis and lack of disease progression despite high viremia.
TL;DR: Analysis of serum biomarkers IFN-γ and IL-10, in association to PRNT and viremia, support the recommendation of use of a ten-fold lower subdose (3,013 IU) of 17DD-YF vaccine.
Abstract: Background: The live attenuated 17DD Yellow Fever vaccine is one of the most successful prophylactic interventions for controlling disease expansion ever designed and utilized in larger scale. However, increase on worldwide vaccine demands and manufacturing restrictions urge for more detailed dose sparing studies. The establishment of complementary biomarkers in addition to PRNT and Viremia could support a secure decision-making regarding the use of 17DD YF vaccine subdoses. The present work aimed at comparing the serum chemokine and cytokine kinetics triggered by five subdoses of 17DD YF Vaccine. Methods: Neutralizing antibody titers, viremia, cytokines and chemokines were tested on blood samples obtained from eligible primary vaccinees. Results and discussion: The results demonstrated that a fifty-fold lower dose of 17DD-YF vaccine (587 IU) is able to trigger similar immunogenicity, as evidenced by significant titers of anti-YF PRNT. However, only subdoses as low as 3,013 IU elicit viremia kinetics with an early peak at five days after primary vaccination equivalent to the current dose (27,476 IU), while other subdoses show a distinct, lower in magnitude and later peak at day 6 post-vaccination. Although the subdose of 587 IU is able to trigger equivalent kinetics of IL-8/CXCL-8 and MCP-1/CCL-2, only the subdose of 3,013 IU is able to trigger similar kinetics of MIG/CXCL-9, pro-inflammatory (TNF, IFN-γ and IL-2) and modulatory cytokines (IL-5 and IL-10). Conclusions: The analysis of serum biomarkers IFN-γ and IL-10, in association to PRNT and viremia, support the recommendation of use of a ten-fold lower subdose (3,013 IU) of 17DD-YF vaccine.
TL;DR: This study characterized the dynamics of WNV viremia in blood compartments in a longitudinal cohort of 54 WNV‐infected blood donors.
TL;DR: Pigs experimentally infected with the SAVE5 virus had significantly lower viremia level up to 14 days post-infection as well as significantly reduced gross and histological lung lesions when compared to wild-type PRRSV VR2385 virus-infected pigs, indicating the attenuation of the SAVEL5 virus.
TL;DR: It is suggested that rabbit HEV infection may cause more severe hepatitis and prolong the course of the disease, with a possible chronic trend of hepatitis in SPF rabbits.
Abstract: This study focused on investigating the pathogenesis seen in specific-pathogen-free (SPF) rabbits following infection with a homologous rabbit HEV isolate (CHN-BJ-rb14) and comparing it to that seen following infection with a heterologous swine genotype 4 HEV isolate (CHN-XJ-SW13). Three of the four animals inoculated with the homologous rabbit HEV became infected, exhibiting an intermittent viremia, obvious fluctuations of liver function biomarkers alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and persistent fecal virus shedding throughout the nine month study. In addition, liver histopathology showed both chronic inflammation and some degree of fibrosis. Both positive and negative-stranded HEV RNA and HEV antigen expression were detected in liver, brain, stomach, duodenum and kidney from the necropsied rabbits. Inflammation of extrahepatic tissue (duodenum and kidney) was also observed. Three of the four rabbits inoculated with the heterologous genotype 4 swine HEV also became infected, showing similar levels of anti-HEV antibody to that generated following infection with the homologous virus isolate. The duration of both viremia and fecal shedding of virus was however shorter following infection with the heterologous virus and there was no significant elevation of liver function biomarkers. These results suggest that rabbit HEV infection may cause more severe hepatitis and prolong the course of the disease, with a possible chronic trend of hepatitis in SPF rabbits.
TL;DR: Incomplete ART adherence is associated with higher levels of residual HIV-1 viremia, but detectable residual vire Mia can be present despite 100% measured ART adherence.
Abstract: Objectives To evaluate the relationship between incomplete antiretroviral therapy (ART) adherence and levels of residual HIV-1 viremia. Design Medication adherence and residual viremia less than 50 copies/ml were quantified in participants of a cohort of homeless and marginally housed individuals with HIV/AIDS. Methods Participants had at least 6 months of virologic suppression of less than 50 copies/ml and were in the adherence monitoring cohort with monthly unannounced pill counts. Residual viremia was measured by the single-copy assay. Results The median average ART adherence over the prior 1 and 2 months were 94% [interquartile range (IQR) 79-100%] and 93% (IQR 82-98%), respectively. Average ART adherence over the past 2 months was significantly associated with levels of residual HIV viremia (Spearman r = -0.25, P = 0.04). One-third of participants with 100% ART adherence over the past 2 months had detectable residual viremia. On multivariate regression analysis, ART adherence over the past 2 months, but not duration of virologic suppression, CD4 T-cell count or ART regimen, was significantly associated with levels of residual HIV viremia. Detectable residual viremia was associated with virologic failure (>50 copies/ml) on univariate Cox proportional hazard analysis (hazard ratio 2.08, P = 0.02). However, on multivariate analysis, only ART adherence was associated with risk of virologic failure. Conclusion Incomplete ART adherence is associated with higher levels of residual HIV-1 viremia, but detectable residual viremia can be present despite 100% measured ART adherence.
TL;DR: Although transient high viremia was not associated with BK polyomavirus-associated nephropathy, it was associated with worse graft function, and data support the role of surveillance for BK viresmia after transplant.
Abstract: Background and objectives The objective was to study the long-term impact of transient versus persistent BK viremia on kidney transplant outcomes. Design, setting, participants, & measurements In total, 609 recipients who underwent kidney transplant from 2007 to 2011 were screened at months 1–12 for the occurrence of polyomavirus BK viremia; 130 patients (21.7%) developed BK viremia during the first year post-transplant. BK viremia patients were classified according to duration of infection (more or less than 3 months), and BK viral loads (more or less than 10,000 copies/ml) were classified as transient low viremia ( n =42), transient high viremia ( n =18), persistent low viremia ( n =23), and persistent high viremia ( n =47). All patients were followed a median of 36 (3–66) months. The rates of BK polyomavirus–associated nephropathy, acute rejection, and 1-year graft function were compared with the polyomavirus BK–negative control group. Results Patient and graft survival were not significantly different among the groups. Graft function (creatinine; milligrams per deciliter) at 1 year was significantly worse in the persistent high viremia (1.75±0.6) and transient high viremia (1.85±0.7) groups compared with aviremic controls (1.47±0.4; P =0.01 and P =0.01, respectively). The incidence of BK polyomavirus–associated nephropathy was limited to the persistent high viremia group (1.3%, P P =0.01) increased incidence of acute rejection versus aviremic controls (21.5%), transient low viremia (19%), or persistent low viremia (17.3%) groups. Conclusion Low viral load BK viremia, either transient or persistent, was not associated with long-term transplant outcomes. Persistent high viremia was associated with a greater risk for BK polyomavirus–associated nephropathy and subsequent graft dysfunction. Although transient high viremia was not associated with BK polyomavirus–associated nephropathy, it was associated with worse graft function. These data support the role of surveillance for BK viremia after transplant.
TL;DR: Whether improved hepatitis control throughout the first year after transplant could be due to better immune competence (reduced iatrogenic immunosuppression), using TTV viremia as a surrogate marker is investigated.
Abstract: TO THE EDITOR—We read with interest the recent article by Béland et al, detailing torque teno virus (TTV) kinetics in pediatric orthotopic liver transplant (OLT) recipients [1]. Interestingly, the authors show that TTV load increased with the number of immunosuppressive agents received. TTV viremia, which is normally at about 2 log10 in healthy subjects, has been shown to increase (up to 4 log10) in almost every condition of chronic immunosuppression (congenital, acquired, or iatrogenic); our group and others have reported high TTV viremia in congenital mannose-binding lectin deficiencies [2], HIV infection [3], cancer [4], heart and lung transplant [5], and high-dose chemotherapy for lymphomas and myelomas. High TTV viremia correlates with high CD27 dysfunctional Blymphocyte [3] and high CD8CD57 dysfunctional T-lymphocyte [6] counts in peripheral blood. In the setting of solid organ transplant, De Vlaminck et al have recently reported that TTV viremia correlates with intensity of maintenance immunosuppression in heart and lung transplant recipients [5]. In OLT, we and others previously reported that TTV DNA load increased significantly after transplant (P < .001) and that, in accordance with the report by Béland et al, TTV DNA was significantly higher in patients on calcineurin inhibitors plus azathioprine or mycophenolate mofetil (CNI + AZA/MMF) than in patients on CNI alone (P = .04) at 3 months after OLT [7]. Because CNIs have severe toxicities in liver transplant recipients and strong iatrogenic immunosuppression may cause hepatitis B virus (HBV) and hepatitis C virus (HCV) reactivation in OLT recipients, some centers have introduced protocols combining low-dose CNIs and extracorporeal photopheresis (lowCNI + ECP) [8, 9], with positive clinical results (reduced numbers of HCV reactivations [8]).We investigated herewhether such improved hepatitis control throughout the first year after transplant could be due to better immune competence (reduced iatrogenic immunosuppression), using TTV viremia as a surrogate marker. Forty-six adult patients with HBV/ HCV-related cirrhosis undergoing consecutive OLT at the Liver Transplant Centre of the Azienda Ospedaliero– Universitaria Pisana in 2009–2011 were enrolled in the low-CNI + ECP study. Preand posttransplant peripheral blood serum samples were obtained from these patients after they provided written informed consent during ECP visits at 3, 6, and 12 months after transplant. Retrospective preand posttransplant samples from historical controls treated with standard immunosuppression in 1996– 2001, namely, CNI monotherapy (n = 19) or CNI + AZA/MMF (n = 6), were provided by the University of Padua Transplant Centre, as previously published [7]. Cyclosporine A C2 levels were maintained at 800–1200 ng/mL for the first 3 months, then at 600–800 ng/ mL up to 6 months and 400–600 ng/mL up to 12 months after liver transplant. Tacrolimus trough levels were kept at 10–15 ng/mL for the first 6 months, then at 8–12 ng/mL up to 12 months after OLT. Azathioprine (1.5 mg/kg) up until the year 2000 and mycophenolate mofetil (1.5–2 g) thereafter were added when the patient’s serum creatinine level was >200 μmol/L, to minimize the cyclosporine or tacrolimus dosage. In all 3 treatment arms, 70% of all patients received induction immunosuppression
TL;DR: Using the lymphocytic choriomeningitis virus variant clone 13, a prototype of Lassa virus, it is shown that lethal vascular leakage in susceptible mice was completely prevented by type I IFN receptor blockade, suggesting that IFN-I may play a prominent role in hemorrhagic fevers and other acute virus infections associated with severe vascular pathology.
Abstract: The outcome of a viral infection reflects the balance between virus virulence and host susceptibility. The clone 13 (Cl13) variant of lymphocytic choriomeningitis virus—a prototype of Old World arenaviruses closely related to Lassa fever virus—elicits in C57BL/6 and BALB/c mice abundant negative immunoregulatory molecules, associated with T-cell exhaustion, negligible T-cell–mediated injury, and high virus titers that persist. Conversely, here we report that in NZB mice, despite the efficient induction of immunoregulatory molecules and high viremia, Cl13 generated a robust cytotoxic T-cell response, resulting in thrombocytopenia, pulmonary endothelial cell loss, vascular leakage, and death within 6–8 d. These pathogenic events required type I IFN (IFN-I) signaling on nonhematopoietic cells and were completely abrogated by IFN-I receptor blockade. Thus, IFN-I may play a prominent role in hemorrhagic fevers and other acute virus infections associated with severe vascular pathology, and targeting IFN-I or downstream effector molecules may be an effective therapeutic approach.
TL;DR: The mean peak viremia in birds of both species decreased as the age at infection increased from 2 to 42 days, indicating the importance of age of infection on magnitude of vireia in birds from both species, and suggesting that young poultry may be amplifying hosts of importance in disease-endemic regions.
Abstract: Ardeid birds and pigs are known as major amplifying hosts for Japanese encephalitis virus, and ducklings and chickens have been considered to play at best a minor role in outbreaks because of their low or absent viremia. We hypothesized that viremia of sufficient magnitude would develop in young ducklings (Anas platyrhynchos) and chicks (Gallus gallus) for them to serve as reservoir hosts and thereby contribute to the transmission cycle. Infection was associated with reduced weight gain in both species, and ducklings infected at 10 days of age or less showed overt clinical signs of disease. The mean peak viremia in birds of both species decreased as the age at infection increased from 2 to 42 days, indicating the importance of age of infection on magnitude of viremia in birds from both species, and suggesting that young poultry may be amplifying hosts of importance in disease-endemic regions.
TL;DR: It is demonstrated that viral infection in patients before treatment could significantly affect the conversion of the prodrug to its active form; such an effect should be calculated when estimating the dose efficacious for humans.
Abstract: In a recent clinical trial, balapiravir, a prodrug of a cytidine analog (R1479), failed to achieve efficacy (reducing viremia after treatment) in dengue patients, although the plasma trough concentration of R1479 remained above the 50% effective concentration (EC(50)). Here, we report experimental evidence to explain the discrepancy between the in vitro and in vivo results and its implication for drug development. R1479 lost its potency by 125-fold when balapiravir was used to treat primary human peripheral blood mononuclear cells (PBMCs; one of the major cells targeted for viral replication) that were preinfected with dengue virus. The elevated EC(50) was greater than the plasma trough concentration of R1479 observed in dengue patients treated with balapiravir and could possibly explain the efficacy failure. Mechanistically, dengue virus infection triggered PBMCs to generate cytokines, which decreased their efficiency of conversion of R1479 to its triphosphate form (the active antiviral ingredient), resulting in decreased antiviral potency. In contrast to the cytidine-based compound R1479, the potency of an adenosine-based inhibitor of dengue virus (NITD008) was much less affected. Taken together, our results demonstrate that viral infection in patients before treatment could significantly affect the conversion of the prodrug to its active form; such an effect should be calculated when estimating the dose efficacious for humans.
TL;DR: The authors show that the drug efficiently inhibits the RNA polymerase of canine distemper virus (CDV), which is closely related to the measles virus and causes lethal, measles-like disease in ferrets, and suggest that this drug may be useful in the future for preemptive treatment of unprotected human contacts of measles cases.
Abstract: Measles virus is a highly infectious morbillivirus responsible for major morbidity and mortality in unvaccinated humans. The related, zoonotic canine distemper virus (CDV) induces morbillivirus disease in ferrets with 100% lethality. We report an orally available, shelf-stable pan-morbillivirus inhibitor that targets the viral RNA polymerase. Prophylactic oral treatment of ferrets infected intranasally with a lethal CDV dose reduced viremia and prolonged survival. Ferrets infected with the same dose of virus that received post-infection treatment at the onset of viremia showed low-grade viral loads, remained asymptomatic, and recovered from infection, whereas control animals succumbed to the disease. Animals that recovered also mounted a robust immune response and were protected against rechallenge with a lethal CDV dose. Drug-resistant viral recombinants were generated and found to be attenuated and transmission-impaired compared to the genetic parent virus. These findings may pioneer a path toward an effective morbillivirus therapy that could aid measles eradication by synergizing with vaccination to close gaps in herd immunity due to vaccine refusal.
TL;DR: The presence of RV viremia is associated with a significantly higher nasopharyngeal viral load and more severe disease, which suggests that a high nasophylactic viral load is a prerequisite for vireia, and that vire Mia is associatedwith considerable clinical involvement.
Abstract: There are few and partially discordant data regarding nasopharyngeal rhinovirus (RV) load and viremia, and none of the published studies evaluated the two variables together. The aim of this study was to provide new information concerning the clinical relevance of determining nasopharyngeal viral load and viremia when characterising RV infection. Nasopharyngeal swabs were obtained from 251 children upon their admission to hospital because of fever and signs and symptoms of acute respiratory infection in order to identify the virus and determine its nasopharyngeal load, and a venous blood sample was taken in order to evaluate viremia. Fifty children (19.9 %) had RV-positive nasopharyngeal swabs, six (12 %) of whom also had RV viremia: RV-C in four cases (66.6 %), and RV-A and RV-B in one case each. The RV nasopharyngeal load was significantly higher in the children with RV viremia (p < 0.001), who also had a higher respiratory rate (p = 0.02), white blood cell counts (p = 0.008) and C-reactive protein levels (p = 0.006), lower blood O2 saturation levels (P = 0.005), and more often required O2 therapy (p = 0.009). The presence of RV viremia is associated with a significantly higher nasopharyngeal viral load and more severe disease, which suggests that a high nasopharyngeal viral load is a prerequisite for viremia, and that viremia is associated with considerable clinical involvement.
TL;DR: New insights are added into the CPV vaccine persistence in the organism and possible interference with diagnostic tests using real-time PCR.
TL;DR: It is demonstrated that BLT mice are susceptible to infection with clinical DENV isolates, mount virus-specific adaptive immune responses, and respond to antiviral drug treatment, and can be used to test preclinically the efficacy of antiviral drugs.
Abstract: Dengue virus (DENV) is the cause of a potentially life-threatening disease that affects millions of people worldwide. The lack of a small animal model that mimics the symptoms of DENV infection in humans has slowed the understanding of viral pathogenesis and the development of therapies and vaccines. Here, we investigated the use of humanized “bone marrow liver thymus” (BLT) mice as a model for immunological studies and assayed their applicability for preclinical testing of antiviral compounds. Human immune system (HIS) BLT-NOD/SCID mice were inoculated intravenously with a low-passage, clinical isolate of DENV-2, and this resulted in sustained viremia and infection of leukocytes in lymphoid and nonlymphoid organs. In addition, DENV infection increased serum cytokine levels and elicited DENV-2-neutralizing human IgM antibodies. Following restimulation with DENV-infected dendritic cells, in vivo-primed T cells became activated and acquired effector function. An adenosine nucleoside inhibitor of DENV decreased the circulating viral RNA when administered simultaneously or 2 days postinfection, simulating a potential treatment protocol for DENV infection in humans. In summary, we demonstrate that BLT mice are susceptible to infection with clinical DENV isolates, mount virus-specific adaptive immune responses, and respond to antiviral drug treatment. Although additional refinements to the model are required, BLT mice are a suitable platform to study aspects of DENV infection and pathogenesis and for preclinical testing of drug and vaccine candidates.
IMPORTANCE
TL;DR: This work identifies papers with experimentally-infected NHP and estimates the time to- and duration of viremia as well as estimate associations between these and serotype, inoculating dose, viresmia assay, and species of NHP.
TL;DR: The generation of certain CD4 responses is associated with control rather than disease progression, and this suggests that the induction of HIV-specific CD4 T cell responses during acute HIV infection is beneficial overall and does not fuel disease progression.
Abstract: Effector CD4 T cell responses have been shown to be critically involved in the containment and clearance of viral pathogens. However, their involvement in the pathogenesis of HIV infection is less clear, given their additional role as preferred viral targets. We previously demonstrated that the presence of HIV-specific CD4 T cell responses is somewhat associated with HIV control and that specific CD4 T cell functions, such as direct cytolytic activity, can contribute to control of HIV viremia. However, little is known about how the induction of HIV-specific CD4 T cell responses during acute HIV infection influences disease progression and whether responses induced during the early phase of infection are preferentially depleted. We therefore longitudinally assessed, in a cohort of 55 acutely HIV-infected individuals, HIV-specific CD4 T cell responses from acute to chronic infection. Interestingly, we found that the breadth, magnitude, and protein dominance of HIV-specific CD4 T cell responses remained remarkably stable over time. Moreover, we found that the epitopes targeted at a high frequency in acute HIV infection were recognized at the same frequency by HIV-specific CD4 T cells in chronic HIV infection. Interestingly the induction of Gag-specific CD4 T cell responses in acute HIV infection was significantly inversely correlated with viral set point in chronic HIV infection (R = −0.5; P = 0.03), while the cumulative contribution of Env-specific CD4 T cell responses showed the reverse effect. Moreover, individuals with HIV-specific CD4 T cell responses dominantly targeting Gag over Env in acute HIV infection remained off antiretroviral therapy significantly longer (P = 0.03; log rank). Thus, our data suggest that the induction of HIV-specific CD4 T cell responses during acute HIV infection is beneficial overall and does not fuel disease progression. IMPORTANCE CD4 T cells are critical for the clearance and control of viral infections. However, HIV preferentially infects HIV-specific CD4 T cells. Thus, their contribution to the control of HIV viremia is uncertain. Here, we study HIV-specific CD4 T cell responses from acute to chronic HIV infection and show that the generation of certain CD4 responses is associated with control rather than disease progression.
TL;DR: It is demonstrated that zoonotic morbillivirus infections can be controlled by measles vaccination, and although CDV can readily infect primates, measles immunity is protective, and CDV infection is self-limiting.
Abstract: Measles virus (MV) is being considered for global eradication, which would likely reduce compliance with MV vaccination. As a result, children will grow up without MV-specific immunity, creating a potential niche for closely related animal morbilliviruses such as canine distemper virus (CDV). Natural CDV infection causing clinical signs has never been reported in humans, but recent outbreaks in captive macaques have shown that CDV can cause disease in primates. We studied the virulence and tropism of recombinant CDV expressing enhanced green fluorescent protein in naive and measles-vaccinated cynomolgus macaques. In naive animals CDV caused viremia and fever and predominantly infected CD150+ lymphocytes and dendritic cells. Virus was reisolated from the upper and lower respiratory tracts, but infection of epithelial or neuronal cells was not detectable at the time points examined, and the infections were self-limiting. This demonstrates that CDV readily infects nonhuman primates but suggests that additional mutations are necessary to achieve full virulence in nonnatural hosts. Partial protection against CDV was observed in measles-vaccinated macaques, as demonstrated by accelerated control of virus replication and limited shedding from the upper respiratory tract. While neither CDV infection nor MV vaccination induced detectable cross-reactive neutralizing antibodies, MV-specific neutralizing antibody levels of MV-vaccinated macaques were boosted by CDV challenge infection, suggesting that cross-reactive VN epitopes exist. Rapid increases in white blood cell counts in MV-vaccinated macaques following CDV challenge suggested that cross-reactive cellular immune responses were also present. This study demonstrates that zoonotic morbillivirus infections can be controlled by measles vaccination.
IMPORTANCE Throughout history viral zoonoses have had a substantial impact on human health. Given the drive toward global eradication of measles, it is essential to understand the zoonotic potential of animal morbilliviruses. Morbilliviruses are thought to have evolved from a common ancestral virus that jumped species and adapted to new hosts. Recently, canine distemper virus (CDV), a morbillivirus normally restricted to carnivores, caused disease outbreaks in nonhuman primates. Here, we report that experimental CDV infection of monkeys resulted in fever and leukopenia. The virus replicated to high levels in lymphocytes but did not spread to epithelial cells or the central nervous system. Importantly, like measles virus in macaques, the infections were self-limiting. In measles-vaccinated macaques CDV was cleared more rapidly, resulting in limited virus shedding from the upper respiratory tract. These studies demonstrate that although CDV can readily infect primates, measles immunity is protective, and CDV infection is self-limiting.
TL;DR: Exposure to high levels of HIV-1 viremia in utero, even in the absence of perinatal transmission, may affect the infant’s developing immune system, and reinforce the need for optimal treatment of HIV infected pregnant women, and careful follow-up of HEU infants.
Abstract: Reports of increased morbidity and mortality from infectious diseases among HIV Exposed Uninfected (HEU) infants have raised concern about a possible underlying immunodeficiency among them. The objective of this study was to assess the immunological profile of HEU infants born to mothers exhibiting different levels of HIV-1 viremia at the time of delivery. Study subjects were enrolled in the Centre maternel et infantile sur le SIDA (CMIS) mother-child cohort between 1997 and 2010 (n =585). Infant CD4+ T cell, CD8+ T cell and CD19+ B cell counts were assessed at 2 and 6 months of age, and compared among HEU infants in groups defined by maternal viral load (VL) at the time of delivery (VL 1000 copies/ml) in a multivariable analysis. At 2 months of age, infants born to mothers with VL > 1000 copies/ml had lower CD4+ T cell counts compared to those born to mothers with VL 1000 copies/ml. These results suggest that exposure to high levels of HIV-1 viremia in utero, even in the absence of perinatal transmission, may affect the infant’s developing immune system. While further work needs to be done to confirm these findings, they reinforce the need for optimal treatment of HIV infected pregnant women, and careful follow-up of HEU infants.
TL;DR: This protocol facilitates rapid and cost-effective generation of virus-specific TCLs, which appear to provide an effective treatment option for patients after hematopoietic stem cell transplantation.
Abstract: Adoptive immunotherapy against viral infections is a promising treatment option for patients after hematopoietic stem cell transplantation. However, the generation of virus-specific T cells is either cost-intensive or time-consuming. We developed the first GMP-compliant protocol to generate donor-derived adenovirus (HAdV), cytomegalovirus, and Epstein-Barr virus-specific T-cell lines (TCLs) within 12 days by the use of overlapping polypeptides derived from different viruses in combination with IL-15. Two patients after undergoing haploidentical hematopoietic stem cell transplantation with HAdV viremia displaying rising viral loads despite treatment with cidofovir received 1×10 donor-derived short-term expanded HAdV-specific TCLs per kg body weight. In both patients, HAdV-specific T cells could be detected by IFN-γ-ELISpot 30 and 22 days postinfusion, and resulted in complete clearance or >1.5 log reduction of viral load within 15 and 18 days, respectively. This protocol facilitates rapid and cost-effective generation of virus-specific TCLs, which appear to provide an effective treatment option.