Prevalence, Outcome, and Prevention of Congenital Cytomegalovirus Infection in Neonates Born to Women With Preconception Immunity (CHILd Study)

BACKGROUND

Human cytomegalovirus (HCMV) is the leading infectious cause of congenital disabilities. We designed a prospective study to investigate the rate, outcome, and risk factors of congenital CMV (cCMV) infection in neonates born to immune women, and the potential need and effectiveness of hygiene recommendations in this population.

METHODS

The study was composed of 2 sequential parts: an epidemiology (part 1) and a prevention (part 2) study. Performance of part 2 depended upon a cCMV rate >0.4%. Women enrolled in part 1 did not receive hygiene recommendations. Newborns were screened by HCMV DNA testing in saliva and cCMV was confirmed by urine testing.

RESULTS

Saliva swabs were positive for HCMV DNA in 45/9661 newborns and cCMV was confirmed in 18 cases. The rate of cCMV was .19% (95% confidence interval [CI]: .11-.29%), and 3 out of 18 infants with cCMV had symptoms of CMV at birth. Age, nationality, occupation, and contact with children were similar between mothers of infected and noninfected newborns. Twin pregnancy (odds ratio [OR]: 7.2; 95% CI: 1.7-32.2; P = .037) and maternal medical conditions (OR: 3.9; 95% CI: 1.5-10.1; P = .003) appeared associated with cCMV. Given the rate of cCMV was lower than expected, the prevention part of the study was cancelled.

CONCLUSIONS

Newborns from women with preconception immunity have a low rate of cCMV, which appears to be mostly due to reactivation of the latent virus. Therefore, serological screening in childbearing age would be pivotal to identify HCMV-seropositive women, whose newborns have a low risk of cCMV.

CLINICAL TRIALS REGISTRATION

www.clinicaltrials.gov (NCT03973359).

Smartwatch-based detection of atrial arrhythmia using a deep neural network in a tertiary care hospital

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction

Smartwatch electrocardiograms (SW ECG) have been identified as a promising noninvasive solution to assess heart rhythm abnormalities, especially atrial arrhythmias (AA) which includes atrial fibrillation, atrial flutter and supraventricular tachycardia. This study evaluates the performance of the detection of AA with a smartwatch and compares the accuracy of two algorithms, the latest version of the original companion application (Apple ECG 2.0 App) and a novel deep neural network (DNN), in a population typical of an electrophysiology department.

Purpose

Determine if a novel DNN can improve the detection of AA on SW ECG in a tertiary care hospital.

Methods

101 patients from the electrophysiology department of one tertiary center were included in this ongoing study. Three simultaneous ECGs were collected for each patient: one 12-lead ECG (Mindray BeneHeart R12) and two SW ECGs (Apple Watch) taken from the left wrist (SWw ECG) and the lower left abdomen (SWa ECG). 12-lead ECGs were adjudicated by a blinded expert electrophysiologist as 52 AA and 49 not AA and considered as gold standard. The SW ECGs were processed by the ECG 2.0 App and the DNN in parallel. The proportions of inconclusive diagnoses returned and the performances were assessed and compared.

Results

Overall, the ECG 2.0 App yielded inconclusive diagnoses for 19% (19/101) of all SWw ECGs while the DNN reduced that number to 0% (0/101). A similar result holds for SWa ECGs (Figure 1). Regarding the detection of AA from SWw ECGs, the ECG 2.0 App had a sensitivity of 81% (95% CI, 67%-90%), a specificity of 97% (95% CI, 87%-100%) and an accuracy of 89% (95% CI, 80%-94%) while the DNN had a sensitivity of 92% (95% CI, 82%-97%), a specificity of 90% (95% CI, 78%-96%) and an accuracy of 91% (95% CI, 84%-95%). For SWa ECGs (Figure 2), the sensitivity of the DNN was found significantly higher compared to the ECG 2.0 App: 96% (95% CI, 89%-98%) vs 76% (95% CI, 61%-87%). Conclusion(s): A novel DNN algorithm decreased the number of inconclusive diagnostics in the detection of AA from SW ECG from around 20% to 0%, which could help limit the overreading time spent by the physicians. Excluding inconclusive diagnostics, we observed no significant difference in performance between the two algorithms except for the sensitivity for SW ECG taken from the abdomen where the DNN outperforms the ECG 2.0 App. Routine application of this SW ECG analysis in tertiary care hospitals offers significant promise in arrhythmia diagnosis.

Human cytomegalovirus non-primary infection during pregnancy: antibody response, risk factors and newborn outcome

OBJECTIVES

Human cytomegalovirus (HCMV) non-primary infections can occur in pregnant women and may result in congenital infection. Comprehensive studies investigating the frequency, characteristics, risk factors and immune response of non-primary infection in pregnancy are missing, while rate of vertical transmission is not known.

METHODS

HCMV non-primary infection was investigated prospectively in 250 pregnant women. Blood and urine samples as well as saliva and vaginal swabs were collected at 13, 21 and 31 weeks of gestation and at delivery. HCMV-DNA and specific IgG and IgM levels were determined.

RESULTS

Overall, 105/250 pregnant women (42.0%) developed non-primary infection. HCMV-DNA was detected more frequently in the vaginal secretions (84/250 of the women, 33.6%) than in the urine (35/250, 14.0%), in the saliva (26/250, 10.4%), and in the blood (7/250, 3.0%). The rate of HCMV non-primary infection increased significantly with the progression of pregnancy (from 12.9% in the first trimesters of gestation to 21.9% at delivery, p<0.01). IgM was detected in 25/250 of the women (10.0%), with no association with non-primary infection, while anti-gB IgG was significantly higher (p<0.01) in women with non-primary infection. Age and close contact with children were not associated with non-primary infection. No woman with non-primary infection transmitted the infection to the fetus (95% confidence interval of transmission rate: 0-3.5%).

CONCLUSION

Although HCMV non-primary infection is frequent during pregnancy, the rate of congenital infection as a consequence of non-primary infection is likely to be ≤3.5%.

Safety, feasibility and prognostic value of stress perfusion CMR in patients with pacemaker

Funding Acknowledgements

Type of funding sources: None.

BACKGROUND

Several studies have shown the excellent prognostic value of stress cardiovascular magnetic resonance (CMR). However, its prognostic value in patients with pacemaker (PM) remains unknown because most studies excluded PM patients.

PURPOSE

This study aimed to assess the prognostic value of vasodilator stress perfusion CMR in patients with PM.

METHODS

Consecutive patients with MR-conditional pacemakers referred for stress perfusion CMR at 1.5 T were followed for the occurrence of major adverse cardiovascular events (MACE), defined by cardiovascular death or nonfatal myocardial infarction. Cox regressions analyses were performed to determine the prognostic value of CMR-parameters. The quality of CMR was rated by two observers blinded to clinical details. Data on pacemaker and leads were collected pre- and post-CMR.

RESULTS

Of 224 patients who completed the stress CMR protocol, 2 patients had inconclusive stress CMR due to artefact and 203 patients (72.9% male, mean age 71.4 ± 8.7 years) completed the follow-up (median [interquartile range], 7.0 [5.2-7.3] years). Among those, 23 experienced a MACE (11.3%). Stress CMR was well tolerated with no major adverse events. All scans were completed successfully with no significant change in lead thresholds or pacing parameters. Overall, the image quality was rated good or excellent in 84.1% of segments. Using Kaplan-Meier analysis, inducible ischemia and late gadolinium enhancement (LGE) were significantly associated with the occurrence of MACE (hazard ratio, HR: 11.80 [95% CI, 4.63-30.30]; and HR: 6.74 [95% CI, 2.47-18.40], both p &lt; 0.001; respectively). In multivariable Cox regression, inducible ischemia and LGE were independent predictors of a higher incidence of MACE (HR: 5.24 [95% CI, 2.61-14.40]; and HR: 2.98 [95% CI, 2.25-4.02]; both p &lt; 0.001; respectively). In patients with ischemia, CMR-related coronary revascularization showed no benefit in reducing MACE (p = 0.25).

CONCLUSION

Stress CMR is safe, feasible and has a good discriminative prognostic value in consecutive patients with PM.

Detection of Genotype-Specific Antibody Responses to Glycoproteins B and H in Primary and Non-Primary Human Cytomegalovirus Infections by Peptide-Based ELISA

BACKGROUND

Strain-specific antibodies to human cytomegalovirus (HCMV) glycoproteins B and H (gB and gH) have been proposed as a potential diagnostic tool for identifying reinfection. We investigated genotype-specific IgG antibody responses in parallel with defining the gB and gH genotypes of the infecting viral strains.

METHODS

Subjects with primary (n = 20) or non-primary (n = 25) HCMV infection were studied. The seven gB (gB1-7) and two gH (gH1-2) genotypes were determined by real-time PCR and whole viral genome sequencing, and genotype-specific IgG antibodies were measured by a peptide-based enzyme-linked immunosorbent assay (ELISA).

RESULTS

Among subjects with primary infection, 73% (n = 8) infected by gB1-HCMV and 63% (n = 5) infected by gB2/3-HCMV had genotype-specific IgG antibodies to gB (gB2 and gB3 are similar in the region tested). Peptides from the rarer gB4-gB7 genotypes had nonspecific antibody responses. All subjects infected by gH1-HCMV and 86% (n = 6) infected by gH2-HCMV developed genotype-specific responses. Among women with non-primary infection, gB and gH genotype-specific IgG antibodies were detected in 40% (n = 10) and 80% (n = 20) of subjects, respectively.

CONCLUSIONS

Peptide-based ELISA is capable of detecting primary genotype-specific IgG responses to HCMV gB and gH, and could be adopted for identifying reinfections. However, about half of the subjects did not have genotype-specific IgG antibodies to gB.

COVID-19 et troubles du rythme

Lors de la pandémie due au virus SARS-CoV2 les troubles du rythme n’ont pas été au premier plan. Cependant, le virus semble atteindre de nombreux organes et le tropisme cardiaque est maintenant bien connu. Les connaissances dans ce domaine sont encore loin d’être exhaustives, mais plusieurs séries publiées concernant les patients atteints de la COVID-19 retrouvent une proportion significative de troubles du rythme, dont certains pouvant potentiellement mener à une issue fatale. Ces troubles du rythmes sont principalement supraventriculaires à type de fibrillation atriale (FA) ou flutter, mais également ventriculaire avec des tachycardies ventriculaires (TV) fibrillation ventriculaire (FV) et plus rarement torsades de pointe (TdP). Les causes en sont multiples, du fait de l’atteinte multiorgane du virus et des interactions médicamenteuses potentielles. Par ailleurs, la question de la surveillance de troubles du rythme pouvant émerger à moyen et long terme après une infection reste à explorer.

[Infections in interventional electrophysiology]

The implantation of pacemakers and defibrillators carries the highest risk of infection in interventional electrophysiology. The use of implantable cardiac devices is continually increasing with almost 2 million devices implanted worldwide each year. The recipients' profile may also be associated with an increased risk of infection. Several measures can be implemented to reduce the risk of device-related infection. Systematic antibiotic prophylaxis has proven to be beneficial provided that prescription modalities are respected, especially with respect to the selection of the appropriate molecule and timing of administration prior to the procedure. Despite all the precautions taken during surgery (asepsis, prophylactic antibiotic therapy….) the estimated rate of peri-procedural infection is around 2%. Device related infections are associated with a high rate of morbidity and mortality as well as substantial healthcare costs. Staphylococcus aureus (SA) and epidermidis (SE) are the pathogenic agents involved in most cases. Prevention is crucial given the difficulties in treating such infections because of the near-systematic need to remove the device and antibiotic resistance. Leadless pacemakers and subcutaneous defibrillators are potential alternatives to implantable endocardial devices, albeit with certain limitations. A group of experts has recently issued consensus paper on the prevention, diagnosis and treatment of infections associated with endocardial implantable cardiac devices.

222AI-based strategy enables faster Holter ECG analysis with equivalent clinical accuracy compared to a classical strategy

BACKGROUND

Analysis of Holter recordings can be challenging and time-consuming, therefore requiring significant clinical resources in order to achieve a high-quality diagnosis. Such resources depend largely on the qualifications of the person conducting the analysis and the duration of the recordings. A novel Holter analysis platform has been developed, based on deep neural networks trained with a dataset of one million ECGs, to allow fast and reliable Holter recording analysis.

PURPOSE

This study sought to compare the performance of an artificial intelligence (AI)-based Holter analysis platform using deep learning tools with a classical one used on a daily basis in hospitals (the reference). The main endpoints evaluated were duration to complete the analysis by the physician operating it as well as diagnostic accuracy of each strategy, when platforms are used by electrophysiologists (EPs).

METHODS

For this prospective evaluation, a total of 159 Holter recordings (24-hour) were selected from a large Holter dataset from 1 hospital, with a relatively high prevalence of electrical rhythm and conduction disorders. Recordings were analysed by four EPs using independently both the AI-based and classical analysis platforms. All four EPs had no previous experience with the AI-based platform, except for an introductory 6-hour training session. Three EPs had multiple years of experience with the traditional platform, while one EP had limited experience. For each recording, in addition to the analysis duration, diagnostic accuracy was evaluated through the analysis of the presence or absence of predefined cardiac arrhythmias and conduction disorders (prevalence): pauses (25.2%), ventricular tachycardia (VT, 30.2%), atrial fibrillation (AF, 26.4%), high grade atrioventricular block (AVB, 10.1%) and burden of premature ventricular complex larger than 10% (PVC, 23.9%). Definite diagnostics were established by an expert EP after a careful examination of all available analysis reports. 

RESULTS

Time required for the AI-based analysis was on average 42% shorter compared to the traditional platform (6.65 min vs 11.5 min, p &lt; 0.0001). Regarding accuracy to detect electrical disorders, there was no statistically significant differences between AI-based and classical platforms (AF: 98.7% vs 96.9%, Pause: 99.4% vs 100%, PVC: 98.7% vs 98.7%, VT: 92.5% vs 96.2%, AVB: 98.7% vs 94.3%). CONCLUSION: These preliminary findings suggest that an AI-based strategy to analyse Holter recordings may be highly accurate in detecting cardiac electrical abnormalities, with significant time savings compared to a classical strategy, even for users with no previous experience with the novel AI-based platform. An AI-based Holter analysis platform may contribute to a broader and more resource-efficient adoption of Holter monitoring.

Abstract Figure. analysis duration using each strategy

[Transcatheter aortic valve implantation and conduction disturbances]

Transcatheter aortic valve implantation (TAVI) is currently becoming the treatment of choice for patients with calcific aortic stenosis. Despite several technical improvements, the incidence of conduction disturbances has not diminished and remains TAVI's major complication. These disturbances include the occurrence of left bundle branch block and/or high-grade atrioventricular block often requiring pacemaker implantation. The proximity of the aortic valve to the conduction system (conduction pathways) accounts for the occurrence of these complications. Several factors have been identified as carrying a high risk of conduction disturbances like the presence of pre-existing right bundle branch block, the type of valve implanted, the volume of aortic and mitral calcifications, the size of the annulus and the depth of valve implantation. Left bundle branch block is the most frequent post TAVI conduction disturbance. Whereas the therapeutic strategy for persistent complete atrioventricular block is simple, it becomes complex in the presence of fluctuating changes in PR interval and left bundle branch block duration. The QRS width threshold value (150-160 ms) indicative of the need for pacemaker implantation is still being debated. Although there are currently no recommendations regarding the management of these conduction disturbances, the extension of TAVI indications to patient at low surgical risk calls for a standardization of our practice. However, a decision algorithm was recently proposed by a group of experts composed of interventional cardiologists, electrophysiologists and cardiac surgeons. There are still uncertainties about the appropriate timing of pacemaker implantation and the management of new onset left bundle branch block.

[Cardiac permanent pacemaker after transcatheter aortic valve implantation: A predictive and scientific review]

Transcatheter aortic valve implantation (TAVI) is nowadays a worldwide technique in the field of treating aortic stenosis. One of the main side effects linked to the technique are mostly attached to rhythm disturbances, such as atrioventricular (AV) and intraventricular blocks. Consequently, a pacemaker implantation is often required. That implantation rate is estimated between 8 and 30%, depending on the valve chosen. Thanks to main meta analysis on the subject, it has been managed to isolate the following risks factors for AV block development: preoperative right bundle branch block (RBBB: the most powerful element), complete AV block during the procedure, male gender, a so-called porcelain aorta, the absence of previous valvular surgery, the aortic annulus size (i.e when that size is inferior to the valve's one) and the QRS duration after the procedure (the superior threshold has been set at 128ms for the Corevalve). The currently recommendations advice to implant a pacemaker are as followed: high grade AV block (in the main studies, the implantation occurs within the 5 days after the TAVI), complete and transient AV block during the TAVI, second degree AV block and RBBB associated with first degree AV block. Our article aims to review the arrhythmic issues of TAVI.

Development and persistence of DAA resistance associated mutations in patients failing HCV treatment

BACKGROUND

Direct-acting antiviral agents (DAAs) combined with pegylated-interferon (PegIFN) and ribavirin (RBV) are still a standard treatment in patients with genotype 1HCV infection. However, virologic response could be impaired by baseline or early selection of resistant HCV strains.

OBJECTIVES

The aim of this study was to determine the onset and persistence of resistance-associated mutations (RAMs) in the NS3 and NS5B genes of DAA-naïve patients failing treatment.

STUDY DESIGN

Direct sequencing of HCV NS3 was performed in 49 DAA-naïve patients with HCV genotype 1 infection.

RESULTS

Eight out of 23 patients (34.7%) failed PegIFN/RBV/telaprevir during the 12-weeks of therapy. Treatment failure was associated with the development of RAMs at amino-acids 36,54,80 and 155 of the HCV protease in 6/8 patients (75%). Among patients treated with PegIFN/RBV/boceprevir treatment, 4/18 (22.2%) failed therapy. Of these, 2 (50%) carried virus strains which developed a RAM at amino-acids 54 and 155. Among HCV strains with RAMs, 7 belonged to genotype 1a and 1 to 1b. Finally, in 6/10 (60%) patients, drug-resistant variants could still be detected for up to 3-7 months after stopping therapy.

CONCLUSIONS

A higher rate (p=0.49) of treatment failure was observed in patients receiving telaprevir- compared to the boceprevir-based combination. In addition, compared with genotype 1b, genotype 1a was associated with higher rates (p=0.01) of treatment failure due to virus resistant strains. Resistance testing at baseline and during DAA treatment should be taken into consideration when treating patients with new HCV combination therapies.

L1 gene sequence of a putative novel type human papillomavirus in an immunocompetent patient with glans lichen sclerosus

The identification of a putative novel type human papillomaviruses (HPV) strain related to HPV-RTRX3 in a subject with penile skin warts and glans lichen sclerosus is reported. A beta-HPV-RTRX3-like strain was detected in a immunocompetent patient with glans lichen sclerosus. HPV screening was performed by PCR in L1 gene. The MY fragment showed 99% nt identity with HPV-RTRX3 and 64.5% nt identity with HPV-37. The remaining part of the L1 gene showed similarity with HPV 80, 15, 17, and 37. Based on the presence of penile lichen sclerosus and the HPV-RTRX3-like strain found in our patient, a potential correlation was hypothesized.

Phylogenetic analysis of HIV type 1 CRF02_AG in multiple genes in Italian and African patients living in Italy

Human immunodeficiency virus type 1 (HIV-1) circulating recombinant form (CRF) 02_AG is a major recombinant variant in different geographic areas and is predominant in West and Central Africa. Of particular interest is the increased frequency of CRF02_AG in patients living in Italy. In the present study, phylogenetic analyses were performed on gag, pol (integrase), and env (gp120 and gp41) gene sequences from 34 CRF02_AG-infected patients living in Italy. Thirty out of 34 (89.4%) patients were from western Africa, 3/34 (8.8%) were born in Italy, and 1/34 (2.9%) was from Cuba. Phylogenetic analysis revealed the presence of a well-supported clade (aLRT score>0.75) of sequences only in gp120 and gp41 trees. Evolutionary rate estimation showed a faster evolution for the gp120 gene with respect to the gag, integrase, and gp41 genes. This finding was confirmed by the analysis of interpatient variability. Intrapatient variability was greater in gp120 gene sequences; 10/19 (52.6%; p<0.001) patients had a ratio of dN/dS>1 as compared with gag, integrase, and gp41 gene sequences with dN/dS ratios<1. In summary, phylogenetic analyses of CRF02_AG strains offer a perspective on intrapatient and interpatient variability among CRF02_AG-infected patients living in Italy. In addition, divergent phylogenetic relationships were observed among different genomic regions.

Systematic analysis of human oncogenic viruses in colon cancer revealed EBV latency in lymphoid infiltrates

Background

Environmental factors may play a role in colon cancer. In this view, several studies investigated tumor samples for the presence of various viral DNA with conflicting results.

Findings

We undertook a systematic DNA analysis of 44 consecutive, prospectively collected primary tumor samples by real time and qualitative PCR for viruses of known or potential oncogenic role in humans, including polyomavirus (JCV, BKV, Merkel cell polyomavirus), HPV, HTLV, HHV-8 and EBV. Negative controls consisted of surgical resection margins. No evidence of genomic DNA fragments from tested virus were detected, except for EBV, which was found in a significant portion of tumors (23/44, 52%). Real-time PCR showed that EBV DNA was present at a highly variable content (median 258 copies in 10⁵ cells, range 15–4837). Presence of EBV DNA had a trend to be associated with high lymphocyte infiltration (p = 0.06, χ2 test), and in situ hybridization with EBER1-2 probes revealed latency in a fraction of these lymphoid cells, with just a few scattered plasma cells positive for BZLF-1, an immediate early protein expressed during lytic replication. LMP-1 expression was undetectable by immunohistochemistry.

Conclusions

These results argue against a significant involvement of the tested oncogenic viruses in established colon cancer.

Naturally occurring resistance mutations to inhibitors of HCV NS5A region and NS5B polymerase in DAA treatment-naïve patients

Background

Direct-acting antiviral (DAA) agents target HCV proteins; some of these have already been approved for the treatment of HCV infection, while others are in development. However, selection of DAA-resistant viral variants may hamper treatment. The aim of this study was to illustrate potential natural DAA-resistance mutations in the HCV NS5A and NS5B regions of HCV genotypes 1a and 1b from DAA-naïve patients.

Methods

Direct sequencing of HCV NS5A and NS5B regions was performed in 32 patients infected with HCV genotype 1a and 30 patients infected with HCV genotype 1b; all subjects were naïve to DAAs.

Results

In genotype 1a strains, resistance mutations in NS5A (M28V, L31M and H58P) were observed in 4/32 (12.5%) patients, and resistance mutations in NS5B (V321I, M426L, Y448H, Y452H) were observed in 4/32 (12.5%) patients. In genotype 1b, resistance mutations in NS5A (L28V, L31M, Q54H, Y93H and I280V) were observed in 16/30 (53.3%) patients, while resistance mutations in NS5B (L159F, V321I, C316N, M426L, Y452H, R465G and V499A) were observed in 27/30 (90%) patients.

Conclusions

Mutations conferring DAA resistance were detected in NS5A and NS5B of HCV genotypes 1a and 1b from DAA-naïve patients. Although some mutations confer only a low level of resistance, the presence at baseline of mutated HCV variants should be taken into consideration in the context of DAA therapy.

Complete genome characterization of enterovirus 104 circulating in Northern Italy shows recombinant origin of the P3 region

Human enterovirus 104 (EV-C104) is a member of the Human Enterovirus species C (Family Picornaviridae, Genus Enterovirus) and has been associated with mild respiratory syndromes. At present, only two EV-C104 complete genome sequences from strains detected in Switzerland and Japan have been deposited in GenBank. In this study a complete genome analysis of seven Italian EV-C104 strains was carried out. In addition, VP1 sequence analysis was performed in an additional 5 Italian strains (for a total of 12 strains). The genome length of the seven strains was 7406 nucleotides (nt). The seven genomes showed 91.0-96.9% nucleotide identity with respect to other available EV-C104 complete genomes. The P1 and P2 regions of the Italian strains were closely related to EV-C104 identified in Switzerland, while the P3 region was closely related to the EV-C117 strain. In addition, bootscan analysis showed the presence of one putative recombination breakpoint between the P2 and P3 regions. Based on the trees constructed with partial VP1/2A nucleotide sequences, as well as the 3D partial coding region tree, the Italian strains appear to form a single and independent cluster together with the EV-C104 Japanese strain. In conclusion, a complete phylogenetic analysis of the relationship between EV-C104 and other known HEV-C strains was achieved. In addition, the recombinant origin of EV-C104, which has circulated in Italy and Japan, was demonstrated.

Multiple clusters of A(H1N1)pdm09 virus circulating in severe cases of influenza during the 2010-2011 season: a phylogenetic and molecular analysis of the neuraminidase gene

The molecular characterization of circulating influenza A viruses is crucial to detect mutations potentially involved in increased virulence, drug resistance and immune escape. A molecular and phylogenetic analysis of A(H1N1)pdm09 neuraminidase (NA) gene sequences from different patient categories defined according to the severity of influenza infection were analyzed. A total of 126 influenza A(H1N1)pdm09 positive samples from patients with severe infections in comparison with those with moderate and mild infections was performed in Lombardy (Northern Italy, nearly 10 million inhabitants) during the 2010-2011 season. NA sequences included in this study segregated into five distinct clusters. Nineteen amino acid substitutions were detected exclusively in NA sequences of viruses identified in patients with severe or moderate influenza infection. Three of them (F74S, S79P, E287K) were observed in virus strains with the 222G/N hemagglutinin mutation. None of NA sequences under study had mutations related to the resistance to the NA inhibitors. Four out of 126 (3.2%) NA sequences from patients with severe infection lost a N-linked glycosylation site due to the change from N to K at residue 386. Two additional N-linked glycosylation sites in the NA stalk region (residues 42 and 44) were found in 12 (9.5%) NA sequences. Sporadic NA mutations were detected in NA viral sequences from critically ill patients, and no variants with reduced sensitivity to NA inhibitors were observed either in treated or untreated patients.

Naturally occurring mutations to HCV protease inhibitors in treatment-naïve patients

Background

Protease inhibitors (PIs) to treat hepatitis C (HCV) virus infection have been approved and others are under development.

Results

The aims of this study were to illustrate natural polymorphisms in the HCV protease and measure the frequency of PI resistance mutations in different HCV genotypes from PI-naïve patients.

Direct sequencing of HCV NS3/4A protease was performed in 156 HCV patients naïve to PIs who were infected with genotype 1a (n = 31), 1b (n = 39), 2 (n = 30), 3 (n = 33) and 4 (n = 23).

Amino acid (aa) substitutions associated with HCV PI resistance were found in 17/156 (10.8%) sequences. Mutations V36L, T54S, V55A/I, and Q80K/L were observed in 29% of patients with genotype 1a, and V55F, Q80L/N and M175L in 10% of patients with genotype 1b. The mutation V158M was found in 3% of patients with genotype 2, D168Q was present in 100% of patients with genotype 3 and D168E was observed in 13% of patients with genotype 4. In addition, multiple aa polymorphisms not associated with PI resistance were detected in patients with genotypes 1a, 1b and 4.

Conclusions

Although major PI resistance mutations were not detected, other resistance mutations conferring low level resistance to PIs together with a number of natural polymorphisms were observed in proteases of PI naïve HCV patients. A more extensive analysis is needed to better evaluate the impact of baseline resistance and compensatory mutations in the efficacy of HCV PI treatment.

Comparison of three different methods for the evaluation of IL28 and ITPA polymorphisms in patients infected with HCV

A single nucleotide polymorphism (SNP) upstream of the IL28 gene (rs12979860) has been reported to predict sustained virological response to peginterferon-ribavirin therapy in chronic HCV patients. In addition, two functionally deficient variants (rs1127354 and rs7270101) of inosine triphosphatase (ITPA) were shown to protect against ribavirin (RBV) - induced hemolytic anemia during early stages of treatment. In this study, three methods for detecting IL28 and ITPA mutations were compared to evaluate accuracy, sensitivity costs and turn-around time. IL28 and ITPA variants were detected using genomic DNA from peripheral blood mononuclear cells (PBMCs) of 61 patients with chronic HCV infection by denaturing high-performance liquid chromatography (DHPLC), direct DNA sequencing analysis and Taq Man Real-Time SNP analysis. Complete concordance in the IL28 polymorphism analysis was observed among the three methods. As for ITPA polymorphisms, 60/61 (98.4%) samples were consistent among the three methods, while results for 1/61 (1.64%) samples were concordant by DHPLC and sequencing, and discordant by real-time SNP. All three methods are suitable for routine testing. On the other hand, screening by real-time SNP detection was less expensive and more rapid.

Human cytomegalovirus serum neutralizing antibodies block virus infection of endothelial/epithelial cells, but not fibroblasts, early during primary infection

A panel of human sera exhibited a >or=128-fold higher neutralizing potency against a human cytomegalovirus (HCMV) clinical isolate propagated and tested in endothelial (or epithelial) cells than against the same virus infecting human fibroblasts. In a group of 18 primary infections, the reverse geometric mean titre was in the range of 10-15 in human fibroblasts within the first 3 months after the onset of infection, whereas the endothelial cell infection-neutralizing activity was already present within the first 10 days, reaching median levels of 122, 320 and 545 at respectively 30, 60 and 90 days after onset, then declining slowly. This difference was also confirmed in the majority of reactivated and remote HCMV infections, as well as in a hyperimmune globulin preparation. The antibody response to HCMV pUL131A, pUL130 and pUL128 locus products, which are required for endothelial/epithelial cell infection, provided a potential molecular basis for such a differential neutralizing activity. In addition, monoclonal/monospecific antibodies raised against the pUL131A, pUL130 and pUL128 proteins were found to display an inhibitory activity on HCMV plaque formation and HCMV leukocyte transfer from HCMV-infected cells. Hence, conventional determination of the neutralizing activity of human sera in fibroblasts is misleading. Antibodies to pUL131A, pUL130 and pUL128 appear to display a major HCMV-neutralizing and dissemination-inhibiting activity.

Human cytomegalovirus UL130 protein promotes endothelial cell infection through a producer cell modification of the virion

Human cytomegalovirus (HCMV) growth in endothelial cells (EC) requires the expression of the UL131A-128 locus proteins. In this study, the UL130 protein (pUL130), the product of the largest gene of the locus, is shown to be a luminal glycoprotein that is inefficiently secreted from infected cells but is incorporated into the virion envelope as a Golgi-matured form. To investigate the mechanism of the UL130-mediated promotion of viral growth in EC, we performed a complementation analysis of a UL130 mutant strain. To provide UL130 in trans to viral infections, we constructed human embryonic lung fibroblast (HELF) and human umbilical vein endothelial cell (HUVEC) derivative cell lines that express UL130 via a retroviral vector. When the UL130-negative virus was grown in UL130-complementing HELF, the infectivity of progeny virions for HUVEC was restored to the wild-type level. In contrast, the infectivity of the UL130-negative virus for UL130-complementing HUVEC was low and similar to that of the same virus infecting control noncomplementing HUVEC. The UL130-negative virus, regardless of whether or not it had been complemented in the prior cycle, could form plaques only on UL130-complementing HUVEC, not control HUVEC. Because (i) both wild-type and UL130-transcomplemented virions maintained their infectivity for HUVEC after purification, (ii) UL130 failed to complement in trans the UL130-negative virus when it was synthesized in a cell separate from the one that produced the virions, and (iii) pUL130 is a virion protein, models are favored in which pUL130 acquisition in the producer cell renders HCMV virions competent for a subsequent infection of EC.

The human cytomegalovirus UL45 gene product is a late, virion-associated protein and influences virus growth at low multiplicities of infection

Human cytomegalovirus (HCMV) encodes a protein related to the large (R1) subunit of ribonucleotide reductase (RR), but does not encode the corresponding small (R2) subunit. The R1 homologue, UL45, lacks many catalytic residues, and its impact on deoxyribonucleotide (dNTP) production remains unknown. Here, UL45 is shown to accumulate at late stages of infection and to be a virion tegument protein. To study UL45 function in its genome context, UL45 was disrupted by transposon insertion. The UL45-knockout (UL45-KO) mutant exhibited a growth defect in fibroblasts at a low m.o.i. and also a cell-to-cell spread defect. This did not result from a reduced dNTP supply because dNTP pools were unchanged in resting cells infected with the mutant virus. Irrespective of UL45 expression, all cellular RR subunits - S-phase RR subunits, and the p53-dependent p53R2 - were induced by infection. p53R2 was targeted to the infected cell nucleus, suggesting that HCMV diverts a mechanism normally activated by DNA damage response. Cells infected with the UL45-KO mutant were moderately sensitized to Fas-induced apoptosis relative to those infected with the parental virus. Together with the report on the UL45-KO endotheliotropic HCMV mutant (Hahn et al., J Virol 76, 9551-9555, 2002), these data suggest that UL45 does not share the prominent antiapototic role attributed to the mouse cytomegalovirus homologue M45 (Brune et al., Science 291, 303-305, 2001).