Emerging trends in Lassa fever: redefining the role of immunoglobulin M and inflammation in diagnosing acute infection

BACKGROUND

Lassa fever (LF) is a devastating hemorrhagic viral disease that is endemic to West Africa and responsible for thousands of human deaths each year. Analysis of humoral immune responses (IgM and IgG) by antibody-capture ELISA (Ab-capture ELISA) and Lassa virus (LASV) viremia by antigen-capture ELISA (Ag-capture ELISA) in suspected patients admitted to the Kenema Government Hospital (KGH) Lassa Fever Ward (LFW) in Sierra Leone over the past five years is reshaping our understanding of acute LF.

RESULTS

Analyses in LF survivors indicated that LASV-specific IgM persists for months to years after initial infection. Furthermore, exposure to LASV appeared to be more prevalent in historically non-endemic areas of West Africa with significant percentages of reportedly healthy donors IgM and IgG positive in LASV-specific Ab-capture ELISA. We found that LF patients who were Ag positive were more likely to die than suspected cases who were only IgM positive. Analysis of metabolic and immunological parameters in Ag positive LF patients revealed a strong correlation between survival and low levels of IL-6, -8, -10, CD40L, BUN, ALP, ALT, and AST. Despite presenting to the hospital with fever and in some instances other symptoms consistent with LF, the profiles of Ag negative IgM positive individuals were similar to those of normal donors and nonfatal (NF) LF cases, suggesting that IgM status cannot necessarily be considered a diagnostic marker of acute LF in suspected cases living in endemic areas of West Africa.

CONCLUSION

Only LASV viremia assessed by Ag-capture immunoassay, nucleic acid detection or virus isolation should be used to diagnose acute LASV infection in West Africans. LASV-specific IgM serostatus cannot be considered a diagnostic marker of acute LF in suspected cases living in endemic areas of West Africa. By applying these criteria, we identified a dysregulated metabolic and pro-inflammatory response profile conferring a poor prognosis in acute LF. In addition to suggesting that the current diagnostic paradigm for acute LF should be reconsidered, these studies present new opportunities for therapeutic interventions based on potential prognostic markers in LF.

Clinical and virological factors associated with viremia in pandemic influenza A/H1N1/2009 virus infection

BACKGROUND

Positive detection of viral RNA in blood and other non-respiratory specimens occurs in severe human influenza A/H5N1 viral infection but is not known to occur commonly in seasonal human influenza infection. Recently, viral RNA was detected in the blood of patients suffering from severe pandemic influenza A/H1N1/2009 viral infection, although the significance of viremia had not been previously studied. Our study aims to explore the clinical and virological factors associated with pandemic influenza A/H1N1/2009 viremia and to determine its clinical significance.

METHODOLOGY/PRINCIPAL FINDINGS

Clinical data of patients admitted to hospitals in Hong Kong between May 2009 and April 2010 and tested positive for pandemic influenza A/H1N1/2009 was collected. Viral RNA was detected by reverse-transcription polymerase chain reactions (RT-PCR) targeting the matrix (M) and HA genes of pandemic influenza A/H1N1/2009 virus from the following specimens: nasopharyngeal aspirate (NPA), endotracheal aspirate (ETA), blood, stool and rectal swab. Stool and/ or rectal swab was obtained only if the patient complained of any gastrointestinal symptoms. A total of 139 patients were included in the study, with viral RNA being detected in the blood of 14 patients by RT-PCR. The occurrence of viremia was strongly associated with a severe clinical presentation and a higher mortality rate, although the latter association was not statistically significant. D222G/N quasispecies were observed in 90% of the blood samples.

CONCLUSION

Presence of pandemic influenza A/H1N1/2009 viremia is an indicator of disease severity and strongly associated with D222G/N mutation in the viral hemagglutinin protein.

Functional impairment of central memory CD4 T cells is a potential early prognostic marker for changing viral load in SHIV-infected rhesus macaques

In HIV infection there is a paucity of literature about the degree of immune dysfunction to potentially correlate and/or predict disease progression relative to CD4(+) T cells count or viral load. We assessed functional characteristics of memory T cells subsets as potential prognostic markers for changing viral loads and/or disease progression using the SHIV-infected rhesus macaque model. Relative to long-term non-progressors with low/undetectable viral loads, those with chronic plasma viremia, but clinically healthy, exhibited significantly lower numbers and functional impairment of CD4(+) T cells, but not CD8(+) T cells, in terms of IL-2 production by central memory subset in response to PMA and ionomycine (PMA+I) stimulation. Highly viremic animals showed impaired cytokine-production by all T cells subsets. These results suggest that functional impairment of CD4(+) T cells in general, and of central memory subset in particular, may be a potential indicator/predictor of chronic infection with immune dysfunction, which could be assayed relatively easily using non-specific PMA+I stimulation.

Relationship between clinical signs and transmission of an infectious disease and the implications for control

Control of many infectious diseases relies on the detection of clinical cases and the isolation, removal, or treatment of cases and their contacts. The success of such "reactive" strategies is influenced by the fraction of transmission occurring before signs appear. We performed experimental studies of foot-and-mouth disease transmission in cattle and estimated this fraction at less than half the value expected from detecting virus in body fluids, the standard proxy measure of infectiousness. This is because the infectious period is shorter (mean 1.7 days) than currently realized, and animals are not infectious until, on average, 0.5 days after clinical signs appear. These results imply that controversial preemptive control measures may be unnecessary; instead, efforts should be directed at early detection of infection and rapid intervention.

Cytomegalovirus glycoprotein-B vaccine with MF59 adjuvant in transplant recipients: a phase 2 randomised placebo-controlled trial

BACKGROUND

Cytomegalovirus end-organ disease can be prevented by giving ganciclovir when viraemia is detected in allograft recipients. Values of viral load correlate with development of end-organ disease and are moderated by pre-existing natural immunity. Our aim was to determine whether vaccine-induced immunity could do likewise.

METHODS

We undertook a phase-2 randomised placebo controlled trial in adults awaiting kidney or liver transplantation at the Royal Free Hospital, London, UK. Exclusion criteria were pregnancy, receipt of blood products (except albumin) in the previous 3 months, and simultaneous multiorgan transplantation. 70 patients seronegative and 70 seropositive for cytomegalovirus were randomly assigned from a scratch-off randomisation code in a 1:1 ratio to receive either cytomegalovirus glycoprotein-B vaccine with MF59 adjuvant or placebo, each given at baseline, 1 month and 6 months later. If a patient was transplanted, no further vaccinations were given and serial blood samples were tested for cytomegalovirus DNA by real-time quantitative PCR (rtqPCR). Any patient with one blood sample containing more than 3000 cytomegalovirus genomes per mL received ganciclovir until two consecutive undetectable cytomegalovirus DNA measurements. Safety and immunogenicity were coprimary endpoints and were assessed by intention to treat in patients who received at least one dose of vaccine or placebo. This trial is registered with ClinicalTrials.gov, NCT00299260.

FINDINGS

67 patients received vaccine and 73 placebo, all of whom were evaluable. Glycoprotein-B antibody titres were significantly increased in both seronegative (geometric mean titre 12,537 (95% CI 6593-23,840) versus 86 (63-118) in recipients of placebo recipients; p<0.0001) and seropositive (118,395; 64,503-217,272) versus 24,682 (17,909-34,017); p<0.0001) recipients of vaccine. In those who developed viraemia after transplantation, glycoprotein-B antibody titres correlated inversely with duration of viraemia (p=0.0022). In the seronegative patients with seropositive donors, the duration of viraemia (p=0.0480) and number of days of ganciclovir treatment (p=0.0287) were reduced in vaccine recipients.

INTERPRETATION

Although cytomegalovirus disease occurs in the context of suppressed cell-mediated immunity post-transplantation, humoral immunity has a role in reduction of cytomegalovirus viraemia. Vaccines containing cytomegalovirus glycoprotein B merit further assessment in transplant recipients.

FUNDING

National Institute of Allergy and Infectious Diseases, Grant R01AI051355 and Wellcome Trust, Grant 078332.

SPONSOR

University College London (UCL).

[Laboratory diagnosis of HIV infection, viral tropism and resistance to antiretrovirals]

The accurate diagnosis of HIV infection demands that to consider a positive result, at least three assays with different antigenic base should be used, one of them, Western-Blot being mandatory for confirmation. Fourth generation ELISAs shorten the window phase to 13-15 days, as they now include p24 antigen detection. Proviral DNA or Viral RNA detection by molecular methods have proved useful for addressing complex situations in which serology was inconclusive. Viral load (HIV-RNA) is routinely used to follow-up HIV infected patients and is used for treatment initiation decisions. It is also used to monitor viral failure. When this happens, resistance tests are needed to guide treatment changes. Resistance is also used to assess the transmission of drug resistance to newly diagnosed patients. Finally, before using an anti-CCR5 drug, viral tropism needs to be determined. This can be done using genotypic tests, widely available in many HIV labs, or phenotypic tests, only available at certain sites.

Human herpesvirus 6 and 7 reactivation and disease activity in multiple sclerosis

Recent studies have focused on the associations between human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7), and multiple sclerosis (MS). The aim of this study was to investigate the associations between HHV-6 and HHV-7 reactivation and MS disease activity, and interleukin 12 (IL-12) and tumor necrosis factor α (TNF-α) production.

MATERIAL AND METHODS

The frequency of plasma viremia by nested polymerase chain reaction and transcription of viral mRNA in peripheral blood mononuclear cells by reverse transcriptase-polymerase chain reaction (RT-PCR) of 14 relapsing/remitting (RR) and 14 secondary progressive (SP) MS patients were studied in comparison with clinical manifestation of the disease. Serum concentrations of cytokines IL-12 and TNF-α were analyzed by enzyme-linked immunosorbent assay.

RESULTS

Plasma samples from 25 of the 28 MS patients with estimated latent/persistent HHV-6 and/or HHV-7 infection were examined during relapse and remission/relative remission. HHV-6 reactivation was found in 4 of the 7 RRMS and 4 of the 7 SPMS patients, and HHV-7 reactivation was identified in 3 of the 7 RRMS and 1 of the 7 SPMS patients (all in relapse). In 2 of the 3 RRMS patients without viremia in relapse, HHV-6 mRNA transcription was detected. In RRMS and SPMS patients with active HHV-6 and HHV-7 infection in relapse, the serum concentrations of IL-12 and TNF-α were significantly higher than in those with latent virus infection.

CONCLUSIONS

HHV-6 and HHV-7 reactivation could be implicated in the exacerbation of MS via activation of Th1 lymphocyte subsets.

False positivity of serological tests for hepatitis C virus

BACKGROUND

Hepatitis C virus infection is now one the common infection in Pakistan. Patients are routinely screened by antibody assays. Objective of this study was to assess the viremia in patients labelled as anti-HCV positive by ELISA.

METHODS

It this retrospective study patients labelled as anti HCV positive by ELISA were assessed for HCV RNA by polymerase chain reaction. The 254 HCV positive cases which were analysed by MEIA method on AxSYM System were selected for RNA extraction by RT-PCR upon Cepheid thermal cycler using TaqMan technology and subsequent for amplification.

RESULTS

Out of 254 anti HCV positive by ELISA, viremia was shown in 211 patients; the remaining 43 (16.92%) samples were false positive.

CONCLUSION

Out of a total 254 anti HCV positive patients, 211 had viremia by RT-PCR. The false positivity noted was 16.9%.

Quantification by real-time PCR of the magnitude and duration of leucocyte-associated viraemia in horses infected with neuropathogenic vs. non-neuropathogenic strains of EHV- 1

REASONS FOR PERFORMING STUDY

Neurological disease in horses caused by infection with certain 'paralytic' strains of equine herpesvirus-1 (EHV-1) is a potentially devastating condition the pathogenesis of which is poorly understood. Preliminary observations in both experimentally induced and naturally occurring cases of the central nervous system disease have revealed a more robust cell-associated viraemia in horses infected with paralytic isolates of EHV-1, relative to horses infected with abortigenic isolates. To investigate further this pathogenesis-relevant question, the present study was performed using a greater number of horses and a more precise method for quantification of EHV-1 DNA present in viraemic leucocytes.

OBJECTIVE

To compare the magnitude and duration of leucocyte-associated viraemia in seronegative, age-matched foals following infection with paralytic vs. abortigenic isolates of EHV-1.

METHODS

Peripheral blood mononuclear cells (PBMC) were collected from 20 weanling foals at 2, 4, 7, 9, 11, 14 and 21 days after intranasal inoculation with either paralytic or abortigenic isolates of EHV-1. The amount of EHV-1 DNA present in each PBMC sample was measured by real-time quantitative PCR.

RESULTS

Foals inoculated with paralytic strains of EHV-1 developed both a greater magnitude and longer duration of PBMC-associated viraemia than foals inoculated with abortigenic strains of the virus.

CONCLUSIONS

Both the higher magnitude and longer duration of cell-associated viraemia contribute to the risk for development of neurological signs in horses infected with paralytic strains of EHV-1.

POTENTIAL RELEVANCE

Our results provide empirically derived, scientific data that contributes to a better understanding of the pathogenetic basis for the differing abilities of paralytic and abortigenic strains of EHV-1 to cause post infection central nervous system disease in the horse. The findings identify the importance of minimising the quantitative burden of viraemic leucocytes that follows exposure to the virus, by the use of effective therapeutic antiviral drugs and efficacious prophylactic vaccines that stimulate cytotoxic immune responses against EHV-1 infected cells.

False negative results in high viremia parvovirus B19-samples tested with real-time PCR

Extremely high viremia is observed during some viruses infection, especialy in immunocompromised patients. False negative results of Parvovirus B 19 DNA tests performed with real-time PCR in high viremic samples are reported. The way of fluorescence diagrams analysis and algorithm of positive result confirmation to exclude such phenomenon are proposed.

Significance of anti-HCV signal-to-cutoff ratio in predicting hepatitis C viremia

BACKGROUND/AIMS

Hepatitis C virus (HCV) RNA testing can be performed using qualitative or quantitative assays, and it is still unclear which is more useful as a primary test in patients positive for anti-HCV. The present study evaluated the usefulness of anti-HCV signal-to-cutoff ratio (S/CO ratio) for predicting HCV RNA results.

METHODS

Patients on whom a qualitative HCV RNA test was performed due to a positive anti-HCV enzyme immunoassay were enrolled. Patients were divided into viremia and no-viremia groups according to HCV RNA results. Receiver-operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic accuracy of anti-HCV S/CO for a diagnosis of viremia.

RESULTS

In total, 487 patients were enrolled. HCV RNA was positive in 301 subjects (61.8%). Age, serum ALT level, and anti-HCV S/CO ratio were significantly different between the viremia and no-viremia groups. By ROC curve analysis, anti-HCV S/CO ratio (area, 0.989; 95% confidence interval, 0.981 to 0.998) accurately predicted the presence of viremia, with a cutoff value of 10.9 (sensitivity, 94.4%; specificity, 97.3%).

CONCLUSIONS

Anti-HCV S/CO ratio was found to be highly accurate at predicting HCV viremia. The anti-HCV S/CO ratio can be used to determine whether a quantitative or qualitative HCV RNA test should be used to confirm HCV viremia in patients with a positive anti-HCV by the following criteria: if the anti-HCV S/CO ratio is <10.9, a qualitative HCV RNA test can be used, and if the anti-HCV S/CO ratio is >or=10.9 a quantitative HCV RNA test can be performed.

Asymptomatic reactivation of JC virus in patients treated with natalizumab

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) occurs in a fraction of patients with multiple sclerosis who were treated with natalizumab. Most adults who are infected with the JC virus, the etiologic agent in PML, do not have symptoms. We sought to determine whether exposure to natalizumab causes subclinical reactivation and neurotropic transformation of JC virus.

METHODS

We followed 19 consecutive patients with multiple sclerosis who were treated with natalizumab over an 18-month period, performing quantitative polymerase-chain-reaction assays in blood and urine for JC virus reactivation; BK virus, a JC virus-related polyomavirus, was used as a control. We determined JC virus-specific T-cell responses by means of an enzyme-linked immunospot assay and antibody responses by means of an enzyme-linked immunosorbent assay and analyzed JC virus regulatory-region sequences.

RESULTS

After 12 months of natalizumab therapy, the prevalence of JC virus in the urine of the 19 patients increased from a baseline value of 19% to 63% (P=0.02). After 18 months of treatment, JC virus was detectable in 3 of 15 available plasma samples (20%) and in 9 of 15 available samples of peripheral-blood mononuclear cells (60%) (P=0.02). JC virus regulatory-region sequences in blood samples and in most of the urine samples were similar to those usually found in PML. Conversely, BK virus remained stable in urine and was undetectable in blood. The JC virus-specific cellular immune response dropped significantly between 6 and 12 months of treatment, and variations in the cellular immune response over time tended to be greater in patients in whom JC viremia developed. None of the patients had clinical or radiologic signs of PML.

CONCLUSIONS

Subclinical reactivation of JC virus occurs frequently in natalizumab-treated patients with multiple sclerosis. Viral shedding is associated with a transient drop in the JC virus-specific cellular immune response.

Multicenter quality control study for human cytomegalovirus DNAemia quantification

Standardized protocols and methods for virological monitoring are mandatory for the correct surveillance of human cytomegalovirus (HCMV) infection in transplanted patients receiving pre-emptive therapy. Fifteen Italian viral diagnostic laboratories belonging to different transplantation centers participated in the external Quality Control Programme for Molecular Diagnostics of HCMV-DNA by using two in-house and five commercial methods for HCMV-DNA quantification. The different methods shared 100% specificity, and sensitivity reached 100% when samples containing > 1,000 copies/ml were considered. The variability range was wide (about 2 log10) for samples containing a lower amount of HCMV-DNA (< 1,000 copies/ml), but it decreased with increasing concentrations of HCMV-DNA. For HCMV-DNA levels > or = 5,000 copies/ml, the different methods provided results within a +/- 0.5 log10 variability range, while the 80% range (range in which 80% of results obtained will fall) was within +/- 0.3 log10 or less. An acceptable level of variability was reached among different in-house and commercial methods for HCMV-DNA quantification in samples containing a clinically significant viral DNA amount. Based on these data, standardized cutoffs established for pre-emptive therapy in different transplantation centers should provide comparable clinical and virological results among centers.

Reliability at the lower limits of HIV-1 RNA quantification in clinical samples: a comparison of RT-PCR versus bDNA assays

INTRODUCTION

To explore whether an assay change was responsible for an increasing proportion of patients with undetectable HIV viral loads at our urban HIV clinic, we selected highly stable patients, examining their viral loads before and after changing assays. We compared the proportion with detectable viremia during RT-PCR vs. bDNA periods.

METHODOLOGY/PRINCIPAL FINDINGS

We selected patients with > or =1 viral loads assessed during both RT-PCR and bDNA periods. We included patients with stable CD4 counts, excluding patients with viral loads > or =1,000 copies/ml or any significant changes in therapy. Out of 4500 clinic patients, 419 patients (1588 viral loads) were included. 39% of viral loads were reported as detectable by RT-PCR vs. 5% reported as detectable by bDNA. The mean coefficient of variation was higher before vs. after assay change. We found an odds' ratio of 16.7 for having a viral load >75 copies/ml during the RT-PCR vs. bDNA periods.

DISCUSSION

These data support previous reports, suggesting that bDNA may more reliably discriminate between viral suppression and low level viremia in stable patients on therapy. Low-level viremia, noted more with RT-PCR, may promote unneeded testing, while differences in viral load reliability may impact antiretroviral trial and quality assurance endpoints. Commonly used plasma separator tubes may differentially affect RT-PCR and bDNA results.

[Comparison study of a real-time reverse transcription polymerase chain reaction assay with an enzyme immunoassay and shell vial culture for influenza A and B virus detection in adult patients]

INTRODUCTION

The age of the patients and the type of sample are major problems in the diagnosis of influenza. Most available diagnostic techniques are highly effective in pediatric patients and in nasopharyngeal aspirates. However, in the adult population and using throat swabs, these techniques are much less reliable.

AIM

We performed a prospective study comparing the efficacy of a commercial real-time reverse transcription PCR assay (RT-PCR) with that of an enzyme immunoassay (EIA) or shell vial culture (SV) in the detection of influenza A and B viruses in 125 throat swabs from adults with clinically suspected influenza during the 2007-2008 flu season.

MATERIAL AND METHODS

Throat swabs were subjected to rapid antigen detection for influenza viruses by means of a commercial dot-blot EIA. For the RT-PCR technique, RNA was extracted from 200 microL of each sample by the automated extraction system, EZ1 virus minikit (version 2.0). Genomic amplification of the extracted viral RNA was carried out using the OneStep RT-PCR FluA+FluB automated system with the SmartCycler amplification system. Each sample was inoculated into 2 SV of the MDCK cell line. Turnaround times were calculated from the time specimens were received in the laboratory to the time the result was reported to clinicians.

RESULTS

The EIA system detected 27 (21.6%) positive samples, RT-PCR 62 (49.6%) positive samples, and SV 56 (44.8%) positive samples. Among the 62 positive samples, EIA detected 27 (43.5%), RT-PCR 62 (100%) and SV 56 (90.3%). With the use of RT-PCR, 38.4% of the adults studied were diagnosed on the same day samples were received. Among the total, 67.2% of diagnostic results were obtained within the first 24 hours; turnaround time was 1.1 days.

CONCLUSION

The real-time RT-PCR method studied displayed high sensitivity and specificity in the detection of influenza virus in adult patients, when compared with the conventional techniques. With real-time RT-PCR, large numbers of samples can be rapidly tested and results provided the same day samples are received.

Long-term renal graft function and survival in patients with high-risk for cytomegalovirus infection receiving preemptive therapy

BACKGROUND

Preemptive therapy reduces the risk of cytomegalovirus disease in high-risk kidney transplant patients. The advantage of this strategy is that only a fraction of patients receive antiviral drugs for a limited time, which decreases costs and toxicity but requires frequent monitoring and may not prevent complications of asymptomatic cytomegalovirus replication.

MATERIAL AND METHODS

Long-term graft-function and patient survival of high-risk kidney transplant patients who received preemptive therapy guided by pp65 antigenemia was compared to those whose assay remained negative throughout the first post-transplant year.

RESULTS

Between August 1997 and March 2005, 24 of 272 patients were CMV D+/R-. Thirteen of the 24 (54.2%) developed a positive CMV assay during follow-up; the time between transplant and first positive antigenemia was 66.7 +/- 58.3 days (range 29-251 days). Four patients developed symptoms associated with CMV, one of whom succumbed from complications of CMV neumonitis. Overall, no significant differences were observed in SCr, eGFR, delta SCr, and delta eGFR during a 60-month followup between patients who developed CMV infection or disease and those who remained pp65 antigenemia-negative throughout the first 12 post-transplant months. Additionally, no deaths or graft loss occurred during the long-term follow up of this cohort.

CONCLUSIONS

Our results suggest that in this high risk group of kidney transplant recipients, treating CMV replication using a preemptive strategy during the first posttransplant year is associated with a low rate of CMV complications and probably interferes with the alleged long-term negative indirect effects of CMV on kidney function and survival.

Monitoring of human Cytomegalovirus infection by antigenemia and viremia in the first 100 days following renal transplantation and relation to antiviral strategies

AIM

Human Cytomegalovirus (HCMV) is a relevant pathogen in transplant recipients, particularly in the first three months post-transplantation. The use of antiviral prophylaxis and pre-emptive therapy is able to reduce incidence of HCMV infection and disease. The incidence of HCMV infection and disease in renal transplant recipients in the first 100 days post-transplantation was investigated, in relation with HCMV serological matching and therapeutic management.

METHODS

Incidence of HCMV infection in the first 100 days post-transplantation was evaluated by pp65-antigenemia in 165 patients on a total number of 1241 clinical samples. Patients were divided in four groups according to donor/recipient serological matching: D(-)/R(-) (low risk of HCMV disease), D(-)/R+ and D+/R+ (intermediate risk) and D+/R(-) (high risk). Antiviral strategy (prophylaxis in high risk group; pre-emptive therapy in intermediate risk group, no therapy in low risk group) and immunosuppressive protocol were recorded.

RESULTS

Incidence of antigenemia-positivity was as follows: 0/3 D(-)/R(-) patients; 59/130 (45.4%) D+/R+; 5/16 (31.3%) D(-)/R+; 4/16 D+/R(-). No significative difference was found between the four groups in terms of incidence of antigenemia-positivity in the first 100 days following transplantation. Antigenemia values >50 pp65-positive/2x10(5) peripheral blood leukocytes (used to start pre-emptive therapy) were present in 18/130 (13.8%) D+/R+; 1/16 (6.2%) D+/R(-); 0/16 D(-)/R+. Viral kinetics in patients with HCMV infection was described.

CONCLUSION

No significative difference was found in terms of incidence of HCMV infection in the first 100 days post-transplantation in relation to immunosuppressive protocol and serological matching, suggesting the appropriateness of antiviral strategies and viral monitoring adopted in this setting.

Effect of viral nucleic acid testing on contamination frequency of manufacturing plasma pools

BACKGROUND

In Europe, all plasma pools used for manufacturing of plasma derivatives must be tested negative for hepatitis C virus (HCV) RNA by nucleic acid amplification techniques (NAT) with a defined minimal sensitivity. For a subset of pools, quantitative B19V DNA NAT is also mandatory. NAT for further viral targets was introduced by most of the manufacturers on a voluntary basis. The contamination frequency of plasma pools with HCV RNA, human immunodeficiency virus (HIV)-1 RNA, and hepatitis B virus (HBV) DNA was investigated with representative pools before and after introduction of NAT.

STUDY DESIGN AND METHODS

A total of 873 pools from 1996 and 331 pools from 2006 were analyzed for the detection of HCV RNA, HIV RNA, and HBV DNA with an automated multiplex NAT system. The pools were obtained from different manufacturers and the source material was of European and US origin.

RESULTS

HCV RNA, HIV-1 RNA, and HBV DNA were detectable in plasma pools from 1996 with the following frequencies: 17.8 percent (HCV RNA), 0.8 percent (HIV-1 RNA), and 0.5 percent (HBV DNA). Viral genome concentrations were up to 3 x 10(4) IU HCV RNA per mL and 7 x 10(3) IU HIV RNA per mL, whereas HBV DNA was below the quantitation limit of the quantitative NAT assay. Among the pools from 2006, one pool (0.3%) was found HCV RNA-positive at low titer (<10 IU/mL), whereas no HIV RNA or HBV DNA was detectable in any pool.

CONCLUSION

The results imply that the introduction of NAT systems for the detection of viral genomes has largely reduced the contamination frequency and viral loads of manufacturing plasma pools and thereby improved the safety margin for human medicinal products manufactured from human plasma. Even with NAT, however, low-titer contamination may occur, which will be coped with by virus inactivation steps included into the manufacturing of plasma derivatives.

Fatal adenovirus hepatitis during maintenance therapy for childhood acute lymphoblastic leukemia

Disseminated adenoviral infection with hepatitis is rare in children undergoing standard chemotherapy. We report on a 3(1/2)-year-old male with fatal adenovirus hepatitis receiving maintenance chemotherapy for acute lymphoblastic leukemia (ALL). Adenoviral hepatitis was proven by histology, viral culture, and PCR in a liver biopsy. Quantitative real-time PCR in the peripheral blood showed adenoviral DNA copy number >10(9)/ml. Despite aggressive supportive care and antiviral treatment with cidofovir, the patient died rapidly due to fulminant liver failure. Diagnostic and treatment options for adenovirus infection remain unsatisfactory for these patients. We propose suggestions for diagnosis and therapy.

Development of PCR assays with nested primers specific for differential detection of three human anelloviruses and early acquisition of dual or triple infection during infancy

We recently identified a novel human virus classifiable into a third group in the genus Anellovirus, tentatively designated torque teno midi virus (TTMDV), with a circular DNA genome of 3.2 kb and genomic organization resembling those of torque teno virus (TTV) (3.8 to 3.9 kb) and torque teno mini virus (TTMV) (2.8 to 2.9 kb). TTMDV was characterized by extreme genetic diversity similar to the TTV and TTMV genomes. Taking advantage of universal and virus species-specific primers derived from a highly conserved area located just downstream of the TATA box of the TTV, TTMDV, and TTMV genomes, a PCR method with simultaneous amplification of the genomic DNAs of these three anelloviruses in the first round and subsequent differential amplifications of these viruses in the second round was developed. High prevalence of TTMDV viremia was seen in adults (75/100 [75%]), comparable with the prevalences of TTV viremia (100%) and TTMV viremia (82%). Although none of 10 cord blood samples had detectable TTV, TTMDV, and TTMV DNAs, the prevalences of these three anelloviruses increased with the number of months after birth of the individual and reached 100% for individuals at one year of age. Dual or triple infection of TTV, TTMDV, and/or TTMV was seen in 10 (47.6%) of 21 infants 9 to 180 days of age and more frequently among infants 181 to 364 days of age (20/23 [86.9%]), comparable with the 93.1% (243/261) prevalence among subjects 1 to 81 years of age, indicating early acquisition of dual or triple anellovirus infection during infancy.

[Real-time PCR as an efficient tool for investigating the presence of human herpesvirus 6 DNA]

Human herpesvirus 6 (HHV-6) is a beta-herpesvirus widely spread within a population and has been recognized as a potential significant pathogen in immunocompromised patients. Different clinical manifestations have been described including fever, skin rash, pneumonia, graft rejection and encephalitis. The goal of the study was development of real-time PCR assay for detection of human herpesvirus type 6 DNA in clinical samples, using primers targeting a conserved region of the viral DNA polymerase gene and a specific TaqMan hydrolyzing probe. The analytical sensitivity of assay was tested using serial dilutions of HHV-6 DNA in range between 10(0) and 10(-6). Thirty plasma samples taken from a group of adult recipients of allogeneic HSCT were tested for the presence of HHV-6 DNA in the LightCycler system. For comparison commercial quantitative MutaREAL HHV-6 kit (ALPCO) was used, according to the manufacturer's instructions. Both LightCycler assays, including in-house real-time PCR, detected HHV-6 DNA in 13 specimens. The conclusion is that developed TaqMan-based probes real-time PCR test is very reliable and valuable for detection of low-copy viremia in plasma samples. The high level of sensitivity and accuracy provided by the LightCycler instrument is favorable for the use of this method in the detection of HHV-6 DNA in clinical specimens.

Clinical and pathological characteristics and response to combination therapy of genotype 4 chronic hepatitis C patients: experience from a spanish center

This observational study evaluated the characteristics of genotype 4 chronic hepatitis C (CHC) patients and their response to combination therapy in Spain. 383 patients with CHC, 44 with genotype 4-HCV infection, were investigated. Nineteen genotype 4-HCV infected patients received IFNalpha-2b (3 MU three times weekly) plus ribavirin (1-1.2 g/day) and ten received Peg-IFNalpha-2b (1.5 microg/kg/week) plus ribavirin (1-1.2 g/day) for 12 months. A sustained virological response (SVR) was evaluated. Genotype 4-HCV was detected in 11.5% of patients, and was significantly associated with a higher proportion of infection through intravenous drug use (46% vs 11%; p<0.001), a higher alcohol intake (35% vs. 7%; p<0.001), higher proportion of anti-HBc positivity (41% vs. 22%; p<0.05), lower ALT (87+/-50 vs. 139+/-142 IU/L; p<0.001) and AST (53+/-30 vs. 85+/-126 IU/L; p<0.001) levels, lower viremia (4.1 +/- 7.7 (x 10(5)) vs . 7.3 +/- 9.8 IU(x 10(5) )/mL) p<0.05) and less fibrosis (stage 3-4 in 21% vs. 32%; p<0.06). Sixteen (55%) out of the 29 patients treated with combination therapy achieved a sustained virological response (SVR) while 10 (36%) were non-responders and 3 (9% relapsed. In conclusion, the lower stage of fibrosis, lower viremia and higher SVR rate than genotype 1 suggest a less aggressive pattern of diseased caused by this genotype.

Viremia in human Cowpox virus infection

Background

Several poxviruses can infect humans and cause diseases of varying severity. Besides the eradicated Variola virus that induced high mortality rates, numerous further human pathogenic orthopoxviruses are potentially fatal but generally cause less severe infections. While infection-related viremia was described for Variola virus and seems to be rare for Monkeypox virus, it is still debated for Vaccinia virus. So far, viremia in Cowpox virus-infected humans has not been reported.

Objectives

To estimate the potential risk of Cowpox virus to disseminate and develop severe infections, two Cowpox virus patients were examined for viremia.

Study design

Whole blood, serum and fluid from virus-induced lesions were analyzed by serology or quantitative real-time PCR.

Results

Real-time PCR and sequence analysis of the hemagglutinin gene confirmed Cowpox virus in the lesions of both patients. Serology performed on serum obtained at the same time as the lesion specimens demonstrated orthopoxvirus-specific IgG and IgM antibodies, indicating a recent orthopoxvirus infection. In addition, Cowpox virus DNA was detectable in whole blood, but not in serum, as late as week 4 post-infection.

Conclusions

In contrast to observations following vaccination with Vaccinia virus, DNAemia in patients with localized symptoms of a Cowpox virus infection does not seem to be a rare event. However, its relevance for Cowpox virus pathogenicity has to be elucidated.

Hepatitis C in the HIV-infected patient

Hepatitis C virus (HCV) coinfection in the presence of HIV raises several challenging issues for the treating clinician. Some evidence indicates that concomitant HIV infection alters HCV virology in ways that are relevant for treatment. Pegylated interferon plus ribavirin is the recommended therapy for HCV in HIV-infected patients. Proportionately fewer HIV/HCV-coinfected patients achieve a sustained virologic response (SVR) compared with those infected with HCV alone. Possible reasons for this include higher levels of HCV viremia and inadequate ribavirin exposure. Strategies under study for optimizing therapeutic response include weight-based ribavirin dosing, use of growth factors to avoid dose reduction, and longer duration of therapy. Aggressive management of adverse effects to avoid dose reduction or treatment discontinuation is also crucial. An integrated multidisciplinary team, including a psychiatrist and addictions specialist, can increase the proportion of HIV/HCV-coinfected patients eligible for treatment. Investigational options exist for patients who relapse after treatment is discontinued and for those with a partial virologic response. Promising therapies that are under development include protease and polymerase inhibitors.

Monitoring of polyomavirus BK virus viruria and viremia in renal allograft recipients by use of a quantitative real-time PCR assay: one-year prospective study

We have developed a real-time quantitative PCR (rt-QPCR) assay to detect and kinetically monitor BK virus viruria and viremia in renal transplant recipients (RTRs). A total of 607 urine and 223 plasma samples were collected from 203 individuals including those with BK virus-associated nephropathy (BKVAN) (n = 8), those undergoing routine posttransplant surveillance (SV) (n = 155), those with nontransplant chronic kidney disease (NT-CKD) (n = 20), and healthy living kidney donors (LD) (n = 20). The rt-QPCR assay was found to be highly sensitive and specific, with a wide dynamic range (2.4 to 11 log(10) copies/ml) and very good precision (coefficient of variation, approximately 5.9%). There was a significant difference in the prevalences of viruria and viremia between the BKVAN (100% and 100%) and SV (23% and 3.9%) groups (P < 0.001). No viruria or viremia was detected in LD or in NT-CKD patients. The median (range) peak levels of BK virus viruria and viremia, in log(10) copies/ml, were 10.26 (9.04 to 10.83) and 4.83 (3.65 to 5.86) for the BKVAN group versus 0 (0 to 10.83) and 0 (0 to 5.65) for the SV group, respectively (P < 0.001). When the BK virus load in the urine was <7.0 log(10) copies/ml, no BK virus viremia was detected. When the BK virus load in the urine reached 7.0, 8.0, 9.0, and > or =10.0 log(10) copies/ml, the corresponding detection of BK virus viremia increased to 20, 33, 50, and 100%, respectively. We propose monitoring of BK virus viruria in RTRs, with plasma BK virus load testing reserved for those with viruria levels of > or =7.0 log(10) copies/ml.

Quantitative real-time polymerase chain reaction for evaluating DNAemia due to cytomegalovirus, Epstein-Barr virus, and BK virus in solid-organ transplant recipients

Testing for cytomegalovirus-, Epstein-Barr virus-, and BK virus-specific gene targets in specimens from solid-organ transplant recipients for DNA by quantitative real-time polymerase chain reaction has been implemented in many diagnostic facilities. This technology provides rapid, accurate, and reproducible results for early detection, monitoring, and medical management of patients with these infections. Because these assays are becoming commonly used in clinical practice, the technical variables associated with specimen processing (e.g., nucleic acid extraction, gene target, and result reporting), amplification, and unique patient characteristics (e.g., age, sex, underlying diseases, immune status, and immunosuppressive regimens received) are factors that may influence the understanding and interpretation of test results. We emphasize the need for standardization of existing variables through parallel comparative and proficiency testing, uniform units for expressing results, to provide for clinical correlation with the results of these molecular assays.

Lengths of hepatitis B viremia and antigenemia in blood donors: preliminary evidence of occult (hepatitis B surface antigen-negative) infection in the acute stage

BACKGROUND

The Japanese Red Cross (JRC) implemented a fully automated pooling and nucleic acid amplification test (NAT) system for testing seronegative donations. The JRC sample repository and repeat blood donations allowed for lookback and follow-up studies of hepatitis B virus (HBV) DNA-positive donors, who tested negative for hepatitis B surface antigen (HBsAg) and anti-hepatitis B core antigen in the JRC screening system.

STUDY DESIGN AND METHODS

From February 1, 2000, to March 31, 2003, 17,314,486 units were tested in 50-sample pools with a semiautomated multiplex assay system (AMPLINAT MPX test, Roche). During this period, 328 HBV DNA-positive donations were found. From 26 of these donors, sequential samples were available at short intervals. This enabled us to examine the dynamics of viral markers in acute HBV infection. The length of detectable periods of plasma viremia and antigenemia were estimated by regression analysis from the results obtained in the quantitative polymerase chain reaction assay (JRC) and HBsAg enzyme immunoassay (Auszyme II, AxSYM, Abbott) and chemiluminescence immunoassay (Abbott).

RESULTS

The median length of detectable HBV DNA in individual donation and 20-sample minipool (MP) NAT format was estimated to be 74 and 50 days, respectively, whereas the median length of detectable HBsAg was estimated to be 42 days. Six of the 26 donors were infected with mutant viruses, and 3 of these 6 donors did not develop detectable HBsAg during the entire observation period, despite a moderately high viral load of 10(4) to 10(5) HBV DNA copies per mL.

CONCLUSION

Transmission of mutant virus may cause occult HBV infection in the acute stage. HBV NAT, even in MP configuration, is more effective than HBsAg testing and capable of interdicting infected donors in the pre- and post-HBsAg window periods.

First case of hepatitis C virus transmission by a red blood cell concentrate after introduction of nucleic acid amplification technique screening in Germany: a comparative study with various assays

BACKGROUND AND OBJECTIVES

Pooled nucleic acid amplification techniques (NAT) and donor screening for anti-hepatitis C virus (HCV) have reduced the diagnostic window period of HCV infection in the blood donor population from about 12 to 1 or 2 weeks. During that time, HCV RNA is hardly detectable by pooled or individual donation NAT. Here we describe a case of transfusion-acquired HCV infection from an extremely low-titre donation. After a repeat donor tested positive for HCV, a look-back procedure was initiated. A recipient of a red cell concentrate from the previous donation was identified and found to be infected with HCV as well. We compared several commercial NAT systems for their ability to detect the viraemic plasma.

MATERIALS AND METHODS

Molecular analyses of HCV in donor and recipient samples were performed. The HCV-transmitting plasma was tested using different commercially available qualitative and quantitative NAT assays.

RESULTS

HCV transmission was verified by molecular analyses and was assigned to genotype 2b. NAT with various commercial HCV assays detected the infection erratically in individual donations. However, the detection rate was not directly related to the claimed sensitivity of some HCV NATs.

CONCLUSIONS

HCV transmission can be caused by donations that escape NAT detection even when tested in an individual donation. Comparison of different assays led to results that did not necessarily reflect the expected sensitivities. The need for standard materials representing further HCV genotypes is discussed.

Post-transplant lymphoproliferative disease and other Epstein-Barr virus diseases in allogeneic haematopoietic stem cell transplantation after introduction of monitoring of viral load by polymerase chain reaction

The clinical value of monitoring of Epstein-Barr virus (EBV) viraemia by quantitative polymerase chain reaction during 1 y was evaluated. 39 recipients of allogeneic hematopoietic stem cell transplantation (SCT) were followed. More than 100 EBV genome equivalents (gEq)/ml in blood or plasma were found in 16/39 patients (41%) at 34 d (range 1-139) post-transplant. Seven of these 16 patients developed EBV disease; 3 post-transplant lymphoproliferative disease (PTLD), 1 myelitis, 1 encephalitis and 2 reactivations with fever. EBV diseases were only found in the high-risk group among recipients of mismatched related or unrelated donor grafts or in patients who underwent reduced-intensity conditioning. In this group, 3/20 (15%) developed PTLD. Conditioning with antithymocyte globulin was significantly associated with EBV disease (p<0.01). EBV load in plasma was more strongly associated with EBV disease than viral load in blood. A cut-off level of 1000 gEq/ml plasma distinguished EBV disease from asymptomatic viraemia, but not PTLD from other EBV diseases. Weekly monitoring of EBV load in plasma in high-risk patients in the first 3 months following SCT seems to be of value for prediction of EBV disease. Therapy for PTLD including rituximab was evaluated during 2 y and showed response in 4/6 cases.

Puumala hantavirus viremia diagnosed by real-time reverse transcriptase PCR using samples from patients with hemorrhagic fever and renal syndrome

Puumala virus (PUUV) is the endemic hantavirus in northern Sweden and causes nephropathia epidemica (NE), a milder form of hemorrhagic fever with renal syndrome. There is a need for fast and reliable diagnostics to differentiate the disease from other infections. By aligning virus RNA sequences isolated from 11 different bank voles and one human patient, we designed a real-time reverse transcriptase (RT) PCR method for detection of PUUV RNA. The real-time RT-PCR assay showed linearity from 20 to 2 x 10(6) virus copies with a correlation coefficient above 0.98 to 0.99 for all experiments. The detection threshold for PUUV cDNA was two copies per reaction. A two-step qualitative RT-PCR to detect PUUV RNA showed 100% concordance with the real-time RT-PCR assay. PUUV RNA viremia was detected in 33 of 34 PUUV immunoglobulin M (IgM)-positive patients with typical clinical NE disease from the region of endemicity. One PUUV IgM-negative sample had PUUV RNA, and 4 days later, the patient was IgM positive. Of samples with indeterminate IgM, 43% were PUUV RNA positive. The kinetics of antibody titers and PUUV viremia were studied, and five of six NE patients displayed a decrease in PUUV viremia a few days after disease outbreak coupled with an increase in PUUV IgM and IgG. In one patient with continuously high PUUV RNA levels but low IgM and no IgG response, the infection was lethal. These findings demonstrated that real-time RT-PCR is a useful method for diagnosis of PUUV viremia and for detecting PUUV RNA at early time points, before the appearance of IgM antibodies.

[Investigation of hemodialysis patients in terms of the presence of occult hepatitis B]

The presence of hepatitis B virus (HBV) DNA in case of negative HBV surface antigen (HBsAg) in serum is known as "occult hepatitis B". There are many reports indicating that occult HBV infections are more frequently encountered in case of hepatocellular carcinoma, hemodialysis practice and co-infections with hepatitis C virus (HCV). The aim of this study was to investigate the presence of HBV-DNA in HBsAg negative hemodialysis. patients and subjects who had never experienced hemodialysis. A total of 226 HBsAg negative sera were included to the study, of which 153 were from hemodialysis patients (97 male, 56 female; mean age: 41.3 +/- 5.8 years), and 73 were from non-hemodialyzed individuals (46 male, 27 female; mean age: 36.5 +/- 6.9 years) who had serological evidence of previous HBV and HCV infections. Of these 73 subjects, 41 were anti-HCV positive, 22 were "anti-HBc IgG positive alone", seven were anti-HBc IgG and anti-HBs positive, and three were anti-HBc IgG and anti-HBe positive, while 40 of 153 (26.1%) hemodialysis patients were anti-HCV positive. HBV and HCV markers were detected by commercial enzyme immunoassays (bioMerieux, France and Murex, UK, respectively), and HBV-DNA testing was performed by a commercial real-time polymerase chain reaction (PCR; 5700 and 7700 Sequence Detection System, Applied Biosystems, UK) assay. Nineteen (12.4%) of HBsAg-negative hemodialysis patients and five (6.8%) of the non-hemodialyzed subjects were found positive for HBV-DNA (viral loads were > or =10(4) copies/ml, and 10(3)-10(4) copies/ml, repectively). The rates of occult HBV infection in the anti-HCV positive hemodialysis patients and anti-HCV positive non-hemodialyzed subjects were detected as 27.5% (11/40) and 2.4% (1/41), respectively. These rates in the other groups were found as follows; 7.1% (8/113) in the anti-HCV negative hemodialysis patients, 9.1% (2/22) in the "anti-HBc positive alone" subjects, and 20% (2/10) in the subjects positive for anti-HBc+anti-HBs or anti-HBe. The results of this study indicated that the prevalence of HBV viremia (12.4%) in hemodialysis patients being more prominent in those of anti-HCV positive patients (27.5%) should not be overlooked. In conclusion, the hemodialysis patients should be screened by sensitive PCR-based methods for occult HBV infections, even if they were negative for HBsAg, in order to prevent or at least to decrease the transmission risk of HBV infection which is still an important health problem in dialysis units.

Acute polyarthritis revealing hepatitis E

We report a case of acute hepatitis E occurring in a 51-year-old French woman, revealed by an abrupt onset of polyarthritis involving the ankles and knees followed by the wrists and fingers. Polyarthritis lasted up to 3 months without recurrence. Our case was characterised by a 9-month prolonged viraemia with persistence of specific IgM in the serum. The hepatitis E virus belonged to genotype 3 and may have been contracted in France or during travel to hyperendemic areas. Our case shows that acute polyarthritis could be another systemic manifestation of hepatitis E virus infection.

Cervical shedding of HIV-1 RNA among women with low levels of viremia while receiving highly active antiretroviral therapy

BACKGROUND

Among women with low or undetectable quantities of HIV-1 RNA in plasma, factors associated with genital HIV-1 RNA shedding, including choice of treatment regimen, are poorly characterized.

METHODS

We measured HIV-1 RNA in cervical swab specimens obtained from participants in the Women's Interagency HIV Study who had concurrent plasma viral RNA levels <500 copies/mL, and we assessed factors associated with genital HIV shedding. The study was powered to determine the relative effects of antiretroviral protease inhibitors (PIs) versus nonnucleoside reverse transcriptase inhibitors (NNRTIs) on viral RNA shedding.

RESULTS

Overall, 44 (15%) of 290 women had detectable HIV-1 RNA in cervical specimens. In the final multivariate model, shedding was independently associated with NNRTI (vs. PI) use (odds ratio [OR], 95% confidence interval [CI]: 2.24, 1.13 to 4.45) and illicit drug use (OR, 95% CI: 2.41, 0.96 to 5.69).

CONCLUSIONS

This is the largest study to define risks for genital HIV-1 RNA shedding in women with low/undetectable plasma virus. Shedding in this population was common, and NNRTI-based highly active antiretroviral therapy (HAART) (vs. PI-based HAART) was associated with genital HIV shedding. Further study is required to determine the impact of these findings on transmission of HIV from mother to child or to sexual partners.

Analysis of cytomegalovirus (CMV) viremia using the pp65 antigenemia assay, the amplicor CMV test, and a semi-quantitative polymerase chain reaction test after allogeneic marrow transplantation

A pp65 antigenemia assay for polymorphonuclear leukocytes (PMNLs) (CINAkit Rapid Antigenemia), and a qualitative polymerase chain reaction (PCR) test for plasma 'PCR-P qual' (Amplicor cytomegalovirus [CMV] test) were performed for 126 samples (blood and plasma) obtained from 18 bone marrow transplant patients, over a 9-month surveillance period. Among those samples, 92 were assayed with a semi-quantitative PCR test for PMNLs 'PCR-L quant.' The number of samples with a positive CMV test for antigenemia and PCR-P qual assays was 20.63% and 12.7%, respectively, whereas the PCR-L quant assay was positive in 48 of the 92 samples assayed (52.17%). The rates of concordance of the results of PCR-P qual and antigenemia, PCR-P qual and PCR-L quant, antigenemia and PCR-L quant were 92%, 65.2% and 66.8%, respectively. The analysis of the results for the 92 specimens tested by all 3 methods showed a rate of concordance of 63% among all methods. Good agreement (kappa=0.72) was found only between pp65 Ag and PCR-P qual assays. Clinical disease correlates with an antigenemia high viral load. Three patients had CMV disease despite preemptive therapy, and all of them had graft-versus-host-disease (GVHD). PMNLs-based assays are more efficient in monitoring CMV reactivation, but for high-risk patients with GVHD, more sensitive assays (real-time PCR) must be done.

El virus de la gripe en pediatría. Un motivo de hospitalización

INTRODUCTION

Influenza infection in infants and children has been classically underestimated due to its non-specific symptoms, which sometimes overlap those of other respiratory viruses. Infants under 24 months are a risk group and school-aged children are a major source of influenza infection. The aim of this study was to describe the clinical and epidemiological characteristics of children hospitalized for flu, including co-infections and the differences as compared to other respiratory viruses. The effectiveness of a test for rapid diagnosis of this condition was assessed.

MATERIAL AND METHODS

Prospective, descriptive study in children < 5 years of age hospitalized from 1 December 2003 to 28 February 2004 with respiratory processes or fever of unknown origin. Polymerase chain reaction (PCR) testing for influenza A (IA) and B, respiratory syncytial virus A (RSV-A) and B, and parainfluenza 1, 2 and 3 was performed in nasopharyngeal aspirate, as well as a test for rapid diagnosis of influenza.

RESULTS

A total of 203 samples were included. PCR was positive for influenza in 11.3% (23/203); IA in 21 cases (20 H3N2, 1 H1N1). Co-infections were frequent (10/23), mainly IA with RSV-A. The rapid diagnostic test had a sensitivity of 45.5%. Median age of patients with flu was 4.87 months (5 days-3.5 years); 69.5% were < 24 months. Gastrointestinal symptoms were associated with fever and respiratory symptoms more often than in other viral infections (P < 0.05). Only 2.9% of patients with a recommendation for flu vaccination had received the vaccination.

CONCLUSIONS

Flu is a major cause of hospitalization in infants and children, particularly those aged < 24 months. Early diagnosis of this condition may avoid unnecessary use of additional tests and antibiotics. Vaccination coverage is low; vaccination between 6 and 24 months seems advisable.

[Rapid differential diagnosis of Orthopoxviruses and Herpesviruses based upon multiplex real-time PCR]

OBJECTIVE

Variola virus, belonging to Orthopoxviridae family, is one of the most dangerous human pathogens that could be used as biological weapon. We have developed a new rapid assay, based upon Real-time PCR and melting temperatures analysis of amplicons, for the contemporary detection of Orthopoxvirus, VZV and HSV1-2, that are the most important infectious agents to be considered for differential diagnosis.

METHODS

The target for detection of orthopoxvirus DNA has been a region of the crmB gene which is common to Variola virus and to other old world orthopoxviruses pathogenic for humans. The targets for VZV and HSV1-2 have been ORF 29 and DNA polymerase, respectively. Suitability of the amplified fragments to RFLP or sequencing analysis, to recognize the involved viral species, has been also tested.

RESULT

The selected primers have showed high sensitivity, specificity and compatibility with common amplification conditions. A mean melting temperature difference of 8.7 degree C was observed between the amplicons from the two virus types. Further identification of individual pathogens was made using RFLP analysis.

CONCLUSION

The PCR-based protocol set up in this study for presumptive differential diagnosis of variola and herpesviral infections is rapid and specific and it can be used also to detect other orthopoxviral infections, like monkeypox.

Clinical Impact of GB Virus C Viremia on Patients with HIV Type 1 Infection in the Era of Highly Active Antiretroviral Therapy

BACKGROUND

The influence of GB virus C (GBV-C) viremia on clinical outcomes of patients with human immunodeficiency virus type 1 (HIV-1) infection remains controversial in the era of highly active antiretroviral therapy (HAART).

METHODS

A prospective observational study was conducted to describe the epidemiology of GBV-C viremia and assess its clinical impact on treatment responses to HAART in 385 HIV-1-infected patients during the period from January 1999 through June 2004.

RESULTS

A total of 59 patients (15.3%) had detectable GBV-C RNA viremia during a median observation of 3.6 years (range, 1.0-7.0 years); 47 patients (12.2%) had GBV-C viremia at enrollment, and 12 (3.1%) acquired GBV-C infection during follow-up. Thirty-two (68.1%) of the 47 patients with baseline GBV-C viremia had persistent GBV-C viremia. Compared with patients with clearance of GBV-C viremia (n=15) and patients without detectable GBV-C viremia (n=326), patients with persistent GBV-C viremia were more likely to be men who have sex with men (81.3% vs. 60.4%; P=.02), tended to have lower baseline plasma HIV RNA load (HIV RNA load > or =5 log(10) copies/mL, 31.3% vs. 49.4%; P=.05), and had a higher proportion of isolated anti-hepatitis B core antibody (37.5% vs. 17.2%; P=.005). There was no statistically significant difference in terms of virologic, immunologic, and clinical responses to HAART; occurrence of hepatic events; and mortality among the 3 groups.

CONCLUSIONS

Persistent GBV-C viremia is significantly associated with male-male sex in HIV-infected patients with advanced immunodeficiency, and persistent GBV-C viremia does not confer short-term benefit in patients receiving HAART.

Detection of hepatitis E virus RNA in sera of patients with hepatitis E by polymerase chain reaction

BACKGROUND

The duration of viremia during hepatitis E virus (HEV) infection has rarely been reported. This study was undertaken to detect HEV RNA in sera of patients with hepatitis E and to understand the process of HEV infection more thoroughly.

METHODS

HEV RNA was detected in the serum samples of hospitalized patients with acute hepatitis E by reverse transcriptase-nested polymerase chain reaction (RT-nPCR) using two pairs of primers from open reading frame (ORF) 1 of the HEV genome.

RESULTS

The serum samples from 44 (70%) of 62 patients were positive for HEV RNA. Thirty-two of these patients, with 288 serial serum specimens, were followed up for the whole process, and 24 patients (75%) were positive for HEV RNA. The positive rates declined with the course of the disease, serum HEV RNA persisting for 20.6 days on average after onset of illness. Serum HEV RNA remained positive in 36 (81.8%) of the 44 patients at the time their alanine aminotransferase (ALT) began to decrease. There was no difference in HEV RNA positivity between serum with high levels of HEV antibody (peak P/N ratio > or =4.0) and that with low levels (peak P/N ratio <4.0), with 25 out of 35 and 19 out of 27 (71.4% vs. 70.4%, P>0.05), respectively.

CONCLUSIONS

There is a relatively long period of HEV viremia in patients with hepatitis E. The proportion of HEV viremia and its duration are not directly related to serum ALT values or HEV antibody levels.

Screening for Acute HIV Infection: Lessons Learned

Human immunodeficiency virus (HIV) nucleic acid testing is increasingly being used by researchers and public health screening programs to identify highly infectious, HIV antibody-negative individuals with acute HIV infection. We present cases to illustrate unusual instances of acute HIV screening, which include "window period" testing and the discovery of low-level HIV RNA.

Reacting to an emerging safety threat: West Nile virus in North America

West Nile virus (WNV) entered North America in 1999 and in 2002 was shown to be transfusion transmitted. With competent mosquito and bird vectors throughout the United States and Canada, WNV clinical disease continues at epidemic proportions. Due to these facts, blood donor screening was implemented prior to the 2003 mosquito season and occurs using a variety of strategies. A combination of minipool (MP) nucleic acid amplification testing (NAT) during the " non-season, " coupled with the conversion to the more sensitive individual donation (ID) NAT in epidemic locations during epidemic times, has been successful in detecting approximately 1500 infected blood donors. Assuming that each donation was infectious and manufactured into 1.45 blood components, testing has therefore prevented close to 2200 recipient infections and potential clinical disease. During this same time, transfusion transmission has occurred from seven MP NAT-nonreactive/ID NAT-reactive units (6 in 2003 and 1 in 2004), or a total of 30 transfusion transmitted cases since WNV has been identified in North America. Because WNV occurs in infected blood donors at low concentrations (i.e., lower viral loads than HIV or HCV with the highest viral load of 580,000 copies/mL observed in a blood donor), a trigger strategy that is used in most of the US consisting of two NAT-reactive donations detected by MP NAT and a frequency of 1:1000 or greater has been developed. Since the full implementation of the MP to ID NAT trigger strategy, there have been no documented WNV transfusion transmissions. Because WNV is an acute infection that only occurs seasonally, other strategies have been proposed, such as seasonal testing, which has been implemented successfully in Canada (Quebec), coupled with a screening question used in the " non-season " of whether the donor has been in the US during the past 56 days; if so, WNV NAT is performed. WNV is an example of an emergent agent in which a rapid series of interventions has been successful in controlling transmission through blood transfusion.

Low-level HCV viraemia after initial response during antiviral therapy: transcription-mediated amplification predicts treatment failure

BACKGROUND

In chronic hepatitis C patients with an initial virological response (IVR) during antiviral therapy (that is, HCV RNA becomes negative before week 16 of treatment) the significance of reappearing viraemia below the detection limit of PCR is not known. We studied this phenomenon in subsets of patients.

METHODS

We assessed HCV RNA at weeks 16 and 20 of therapy by PCR and by more sensitive transcription-mediated amplification (TMA) in 23 patients with breakthrough or relapse and in 34 patients with sustained virological response (SVR). All patients participated in a high-dose-interferon induction study for difficult-to-treat patients. Therapy consisted of amantadine hydrochloride and ribavirin, combined with interferon-alpha2b induction during the first 6 weeks and thereafter combined with weekly pegylated interferon-alpha2b.

RESULTS

Among the 57 IVR patients, we detected transient or persistent reappearance of low levels of HCV RNA in 10 of the 23 (43%) patients with eventual breakthrough or relapse; but in none of the 34 SVR patients. In 5 of 10 patients reappearing HCV RNA was only detectable by TMA.

CONCLUSION

Reappearance of low levels of HCV RNA in patients with IVR predicts treatment failure.