Differential Changes in ACPA Fine Specificity and Gene Expression in a Randomized Trial of Abatacept and Adalimumab in Rheumatoid Arthritis.

INTRODUCTION: The biologics abatacept and adalimumab have different mechanisms of action (MoAs). We analyzed data from patients with rheumatoid arthritis treated in AMPLE (NCT00929864) to explore the pharmacodynamic effects of abatacept or adalimumab on anti-citrullinated protein antibodies (ACPAs) and gene expression. METHODS: AMPLE was a phase IIIb, 2-year, randomized, head-to-head trial of abatacept versus adalimumab. Post hoc analyses of baseline anti-cyclic citrullinated peptide-2 (anti-CCP2, an ACPA surrogate) positive (+) status and ACPA fine-specificity profiles over time, as well as transcriptional profiling (peripheral whole blood), were performed. RESULTS: Of 646 patients treated (abatacept, n = 318; adalimumab, n = 328), ACPA and gene expression data were available from 508 and 566 patients, respectively. In anti-CCP2+ patients (n = 388), baseline fine specificities for most ACPAs were highly correlated; over 2 years, levels decreased with abatacept but not adalimumab. By year 2, expression of genes associated with T cell co-stimulation and antibody production was lower for abatacept versus adalimumab; expression of genes associated with proinflammatory signaling was lower for adalimumab versus abatacept. Treatment modulated the expression of T- and B-cell gene signatures, with differences in CD8+ T cells, activated T cells, plasma cells, B cells, natural killer cells (all lower with abatacept versus adalimumab), and polymorphonuclear leukocytes (higher with abatacept versus adalimumab). CONCLUSIONS: In AMPLE, despite similar clinical outcomes, data showed that pharmacodynamic/genetic changes after 2 years of abatacept or adalimumab were consistent with drug MoAs. Further assessment of the relationship between such changes and clinical outcomes, including prediction of response, is warranted. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT00929864.

Mismatch negativity (MMN) to spatial deviants and behavioral spatial discrimination ability in the etiology of auditory verbal hallucinations and thought disorder in schizophrenia.

Persistent auditory verbal hallucinations (AVH) in schizophrenia are increasingly tied to dysfunction at the level of auditory cortex. AVH may reflect in part misattribution of internally generated thoughts to external spatial locations. Here, we investigated the association between persistent AVH and spatial localization abilities assessed both behaviorally and by mismatch negativity (MMN) to location deviants. METHODS: Spatial- and tonal- discrimination abilities were assessed in patients (n=20) and controls (n=20) using free-field tones. MMN was assessed to spatial-location-, pitch- and duration-deviants. AVH and thought disorder were assessed using clinical evaluation. RESULTS: As predicted, patients showed significant reductions in behavioral spatial-discrimination (p<0.0001) and tone-matching (p<0.001) ability, along with impaired MMN generation to location (p<0.03) and pitch (p<0.05) deviants. Hallucinating (AVH+) and non-hallucinating (AVH-) subjects showed similar deficits in location MMN to left-hemifield stimuli (p<0.0001 vs. control). By contrast, AVH- patients differed significantly from controls (p=0.009) and AVH+ patients (p=0.018) for MMN to right-lateral hemifield (left auditory cortex) stimuli, whereas AVH+ patients showed paradoxically preserved MMN generation (p=0.99 vs. controls). Severity of thought disorder correlated with impaired spatial discrimination, especially to right-hemifield stimuli (p=0.013), but did not correlate significantly with MMN or tone matching deficits. CONCLUSION: These findings demonstrate a significant relationship between auditory cortical spatial localization abilities and AVH susceptibility, with relatively preserved function of left vs. right auditory cortex predisposing to more severe AVH, and support models that attribute persistent AVH to impaired source-monitoring. The findings suggest new approaches for therapeutic intervention for both AVH and thought disorder in schizophrenia.

Identification of biomarkers of response to abatacept in patients with SLE using deconvolution of whole blood transcriptomic data from a phase IIb clinical trial.

OBJECTIVE: To characterise patients with active SLE based on pretreatment gene expression-defined peripheral immune cell patterns and identify clusters enriched for potential responders to abatacept treatment. METHODS: This post hoc analysis used baseline peripheral whole blood transcriptomic data from patients in a phase IIb trial of intravenous abatacept (~10 mg/kg/month). Cell-specific genes were used with a published deconvolution algorithm to identify immune cell proportions in patient samples, and unsupervised consensus clustering was generated. Efficacy data were re-analysed. RESULTS: Patient data (n=144: abatacept: n=98; placebo: n=46) were grouped into four main clusters (C) by predominant characteristic cells: C1-neutrophils; C2-cytotoxic T cells, B-cell receptor-ligated B cells, monocytes, IgG memory B cells, activated T helper cells; C3-plasma cells, activated dendritic cells, activated natural killer cells, neutrophils; C4-activated dendritic cells, cytotoxic T cells. C3 had the highest baseline total British Isles Lupus Assessment Group (BILAG) scores, highest antidouble-stranded DNA autoantibody levels and shortest time to flare (TTF), plus trends in favour of response to abatacept over placebo: adjusted mean difference in BILAG score over 1 year, -4.78 (95% CI -12.49 to 2.92); median TTF, 56 vs 6 days; greater normalisation of complement component 3 and 4 levels. Differential improvements with abatacept were not seen in other clusters, except for median TTF in C1 (201 vs 109 days). CONCLUSIONS: Immune cell clustering segmented disease severity and responsiveness to abatacept. Definition of immune response cell types may inform design and interpretation of SLE trials and treatment decisions. TRIAL REGISTRATION NUMBER: NCT00119678; results.

An acetyltransferase-independent function of Eso1 regulates centromere cohesion.

Eukaryotes contain three essential Structural Maintenance of Chromosomes (SMC) complexes: cohesin, condensin, and Smc5/6. Cohesin forms a ring-shaped structure that embraces sister chromatids to promote their cohesion. The cohesiveness of cohesin is promoted by acetylation of N-terminal lysines of the Smc3 subunit by the acetyltransferases Eco1 in Saccharomyces cerevisiae and the homologue, Eso1, in Schizosaccharomyces pombe. In both yeasts, these acetyltransferases are essential for cell viability. However, whereas nonacetylatable Smc3 mutants are lethal in S. cerevisiae, they are not in S. pombe We show that the lethality of a temperature-sensitive allele of eso1 (eso1-H17) is due to activation of the spindle assembly checkpoint (SAC) and is associated with premature centromere separation. The lack of cohesion at the centromeres does not correlate with Psm3 acetylation or cohesin levels at the centromeres, but is associated ith significantly reduced recruitment of the cohesin regulator Pds5. The SAC activation in this context is dependent on Smc5/6 function, which is required to remove cohesin from chromosome arms but not centromeres. The mitotic defects caused by Smc5/6 and Eso1 dysfunction are cosuppressed in double mutants. This identifies a novel function (or functions) for Eso1 and Smc5/6 at centromeres and extends the functional relationships between these SMC complexes.

Virome Capture Sequencing Enables Sensitive Viral Diagnosis and Comprehensive Virome Analysis.

Insensitivity and technical complexity have impeded the implementation of high-throughput nucleic acid sequencing in differential diagnosis of viral infections in clinical laboratories. Here, we describe the development of a virome capture sequencing platform for vertebrate viruses (VirCapSeq-VERT) that increases the sensitivity of sequence-based virus detection and characterization. The system uses ~2 million probes that cover the genomes of members of the 207 viral taxa known to infect vertebrates, including humans. A biotinylated oligonucleotide library was synthesized on the NimbleGen cleavable array platform and used for solution-based capture of viral nucleic acids present in complex samples containing variable proportions of viral and host nucleic acids. The use of VirCapSeq-VERT resulted in a 100- to 10,000-fold increase in viral reads from blood and tissue homogenates compared to conventional Illumina sequencing using established virus enrichment procedures, including filtration, nuclease treatments, and RiboZero rRNA subtraction. VirCapSeq-VERT had a limit of detection comparable to that of agent-specific real-time PCR in serum, blood, and tissue extracts. Furthermore, the method identified novel viruses whose genomes were approximately 40% different from the known virus genomes used for designing the probe library. The VirCapSeq-VERT platform is ideally suited for analyses of virome composition and dynamics. IMPORTANCE : VirCapSeq-VERT enables detection of viral sequences in complex sample backgrounds, including those found in clinical specimens, such as serum, blood, and tissue. The highly multiplexed nature of the system allows both the simultaneous identification and the comprehensive genetic characterization of all known vertebrate viruses, their genetic variants, and novel viruses. The operational simplicity and efficiency of the VirCapSeq-VERT platform may facilitate transition of high-throughput sequencing to clinical diagnostic as well as research applications.

Transcriptome Profiling of the Virus-Induced Innate Immune Response in Pteropus vampyrus and Its Attenuation by Nipah Virus Interferon Antagonist Functions.

UNLABELLED: Bats are important reservoirs for several viruses, many of which cause lethal infections in humans but have reduced pathogenicity in bats. As the innate immune response is critical for controlling viruses, the nature of this response in bats and how it may differ from that in other mammals are of great interest. Using next-generation transcriptome sequencing (mRNA-seq), we profiled the transcriptional response of Pteropus vampyrus bat kidney (PVK) cells to Newcastle disease virus (NDV), an avian paramyxovirus known to elicit a strong innate immune response in mammalian cells. The Pteropus genus is a known reservoir of Nipah virus (NiV) and Hendra virus (HeV). Analysis of the 200 to 300 regulated genes showed that genes for interferon (IFN) and antiviral pathways are highly upregulated in NDV-infected PVK cells, including genes for beta IFN, RIG-I, MDA5, ISG15, and IRF1. NDV-infected cells also upregulated several genes not previously characterized to be antiviral, such as RND1, SERTAD1, CHAC1, and MORC3. In fact, we show that MORC3 is induced by both IFN and NDV infection in PVK cells but is not induced by either stimulus in human A549 cells. In contrast to NDV infection, HeV and NiV infection of PVK cells failed to induce these innate immune response genes. Likewise, an attenuated response was observed in PVK cells infected with recombinant NDVs expressing the NiV IFN antagonist proteins V and W. This study provides the first global profile of a robust virus-induced innate immune response in bats and indicates that henipavirus IFN antagonist mechanisms are likely active in bat cells. IMPORTANCE: Bats are the reservoir host for many highly pathogenic human viruses, including henipaviruses, lyssaviruses, severe acute respiratory syndrome coronavirus, and filoviruses, and many other viruses have also been isolated from bats. Viral infections are reportedly asymptomatic or heavily attenuated in bat populations. Despite their ecological importance to viral maintenance, research into their immune system and mechanisms for viral control has only recently begun. Nipah virus and Hendra virus are two paramyxoviruses associated with high mortality rates in humans and whose reservoir is the Pteropus genus of bats. Greater knowledge of the innate immune response of P. vampyrus bats to viral infection may elucidate how bats serve as a reservoir for so many viruses.

Mitochondrial division is requisite to RAS-induced transformation and targeted by oncogenic MAPK pathway inhibitors.

Mitochondrial division is essential for mitosis and metazoan development, but a mechanistic role in cancer biology remains unknown. Here, we examine the direct effects of oncogenic RAS(G12V)-mediated cellular transformation on the mitochondrial dynamics machinery and observe a positive selection for dynamin-related protein 1 (DRP1), a protein required for mitochondrial network division. Loss of DRP1 prevents RAS(G12V)-induced mitochondrial dysfunction and renders cells resistant to transformation. Conversely, in human tumor cell lines with activating MAPK mutations, inhibition of these signals leads to robust mitochondrial network reprogramming initiated by DRP1 loss resulting in mitochondrial hyper-fusion and increased mitochondrial metabolism. These phenotypes are mechanistically linked by ERK1/2 phosphorylation of DRP1 serine 616; DRP1(S616) phosphorylation is sufficient to phenocopy transformation-induced mitochondrial dysfunction, and DRP1(S616) phosphorylation status dichotomizes BRAF(WT) from BRAF(V600E)-positive lesions. These findings implicate mitochondrial division and DRP1 as crucial regulators of transformation with leverage in chemotherapeutic success.

Deep sequencing identifies noncanonical editing of Ebola and Marburg virus RNAs in infected cells.

UNLABELLED: Deep sequencing of RNAs produced by Zaire ebolavirus (EBOV) or the Angola strain of Marburgvirus (MARV-Ang) identified novel viral and cellular mechanisms that diversify the coding and noncoding sequences of viral mRNAs and genomic RNAs. We identified previously undescribed sites within the EBOV and MARV-Ang mRNAs where apparent cotranscriptional editing has resulted in the addition of non-template-encoded residues within the EBOV glycoprotein (GP) mRNA, the MARV-Ang nucleoprotein (NP) mRNA, and the MARV-Ang polymerase (L) mRNA, such that novel viral translation products could be produced. Further, we found that the well-characterized EBOV GP mRNA editing site is modified at a high frequency during viral genome RNA replication. Additionally, editing hot spots representing sites of apparent adenosine deaminase activity were found in the MARV-Ang NP 3'-untranslated region. These studies identify novel filovirus-host interactions and reveal production of a greater diversity of filoviral gene products than was previously appreciated. IMPORTANCE: This study identifies novel mechanisms that alter the protein coding capacities of Ebola and Marburg virus mRNAs. Therefore, filovirus gene expression is more complex and diverse than previously recognized. These observations suggest new directions in understanding the regulation of filovirus gene expression.

Visual displays that directly interface and provide read-outs of molecular states via molecular graphics processing units.

The monitoring of molecular systems usually requires sophisticated technologies to interpret nanoscale events into electronic-decipherable signals. We demonstrate a new method for obtaining read-outs of molecular states that uses graphics processing units made from molecular circuits. Because they are made from molecules, the units are able to directly interact with molecular systems. We developed deoxyribozyme-based graphics processing units able to monitor nucleic acids and output alphanumerical read-outs via a fluorescent display. Using this design we created a molecular 7-segment display, a molecular calculator able to add and multiply small numbers, and a molecular automaton able to diagnose Ebola and Marburg virus sequences. These molecular graphics processing units provide insight for the construction of autonomous biosensing devices, and are essential components for the development of molecular computing platforms devoid of electronics.

Middle East respiratory syndrome coronavirus quasispecies that include homologues of human isolates revealed through whole-genome analysis and virus cultured from dromedary camels in Saudi Arabia.

ABSTRACT Complete Middle East respiratory syndrome coronavirus (MERS-CoV) genome sequences were obtained from nasal swabs of dromedary camels sampled in the Kingdom of Saudi Arabia through direct analysis of nucleic acid extracts or following virus isolation in cell culture. Consensus dromedary MERS-CoV genome sequences were the same with either template source and identical to published human MERS-CoV sequences. However, in contrast to individual human cases, where only clonal genomic sequences are reported, detailed population analyses revealed the presence of more than one genomic variant in individual dromedaries. If humans are truly infected only with clonal virus populations, we must entertain a model for interspecies transmission of MERS-CoV wherein only specific genotypes are capable of passing bottleneck selection. IMPORTANCE In most cases of Middle East respiratory syndrome (MERS), the route for human infection with the causative agent, MERS coronavirus (MERS-CoV), is unknown. Antibodies to and viral nucleic acids of MERS-CoV have been found in dromedaries, suggesting the possibility that they may serve as a reservoir or vector for human infection. However, neither whole viral genomic sequence nor infectious virus has been isolated from dromedaries or other animals in Saudi Arabia. Here, we report recovery of MERS-CoV from nasal swabs of dromedaries, demonstrate that MERS-CoV whole-genome consensus sequences from dromedaries and humans are indistinguishable, and show that dromedaries can be simultaneously infected with more than one MERS-CoV. Together with data indicating widespread dromedary infection in the Kingdom of Saudi Arabia, these findings support the plausibility of a role for dromedaries in human infection.

Analytical validation of whole exome and whole genome sequencing for clinical applications.

BACKGROUND: Whole exome and genome sequencing (WES/WGS) is now routinely offered as a clinical test by a growing number of laboratories. As part of the test design process each laboratory must determine the performance characteristics of the platform, test and informatics pipeline. This report documents one such characterization of WES/WGS. METHODS: Whole exome and whole genome sequencing was performed on multiple technical replicates of five reference samples using the Illumina HiSeq 2000/2500. The sequencing data was processed with a GATK-based genome analysis pipeline to evaluate: intra-run, inter-run, inter-mode, inter-machine and inter-library consistency, concordance with orthogonal technologies (microarray, Sanger) and sensitivity and accuracy relative to known variant sets. RESULTS: Concordance to high-density microarrays consistently exceeds 97% (and typically exceeds 99%) and concordance between sequencing replicates also exceeds 97%, with no observable differences between different flow cells, runs, machines or modes. Sensitivity relative to high-density microarray variants exceeds 95%. In a detailed study of a 129 kb region, sensitivity was lower with some validated single-base insertions and deletions "not called". Different variants are "not called" in each replicate: of all variants identified in WES data from the NA12878 reference sample 74% of indels and 89% of SNVs were called in all seven replicates, in NA12878 WGS 52% of indels and 88% of SNVs were called in all six replicates. Key sources of non-uniformity are variance in depth of coverage, artifactual variants resulting from repetitive regions and larger structural variants. CONCLUSION: We report a comprehensive performance characterization of WES/WGS that will be relevant to offering laboratories, consumers of genome sequencing and others interested in the analytical validity of this technology.

H2A.Z-dependent regulation of cohesin dynamics on chromosome arms.

Structural maintenance of chromosomes (SMC) complexes and DNA topoisomerases are major determinants of chromosome structure and dynamics. The cohesin complex embraces sister chromatids throughout interphase, but during mitosis most cohesin is stripped from chromosome arms by early prophase, while the remaining cohesin at kinetochores is cleaved at anaphase. This two-step removal of cohesin is required for sister chromatids to separate. The cohesin-related Smc5/6 complex has been studied mostly as a determinant of DNA repair via homologous recombination. However, chromosome segregation fails in Smc5/6 null mutants or cells treated with small interfering RNAs. This also occurs in Smc5/6 hypomorphs in the fission yeast Schizosaccharomyces pombe following genotoxic and replication stress, or topoisomerase II dysfunction, and these mitotic defects are due to the postanaphase retention of cohesin on chromosome arms. Here we show that mitotic and repair roles for Smc5/6 are genetically separable in S. pombe. Further, we identified the histone variant H2A.Z as a critical factor to modulate cohesin dynamics, and cells lacking H2A.Z suppress the mitotic defects conferred by Smc5/6 dysfunction. Together, H2A.Z and the SMC complexes ensure genome integrity through accurate chromosome segregation.

An upstream open reading frame modulates ebola virus polymerase translation and virus replication.

Ebolaviruses, highly lethal zoonotic pathogens, possess longer genomes than most other non-segmented negative-strand RNA viruses due in part to long 5' and 3' untranslated regions (UTRs) present in the seven viral transcriptional units. To date, specific functions have not been assigned to these UTRs. With reporter assays, we demonstrated that the Zaire ebolavirus (EBOV) 5'-UTRs lack internal ribosomal entry site function. However, the 5'-UTRs do differentially regulate cap-dependent translation when placed upstream of a GFP reporter gene. Most dramatically, the 5'-UTR derived from the viral polymerase (L) mRNA strongly suppressed translation of GFP compared to a ß-actin 5'-UTR. The L 5'-UTR is one of four viral genes to possess upstream AUGs (uAUGs), and ablation of each uAUG enhanced translation of the primary ORF (pORF), most dramatically in the case of the L 5'-UTR. The L uAUG was sufficient to initiate translation, is surrounded by a "weak" Kozak sequence and suppressed pORF translation in a position-dependent manner. Under conditions where eIF2α was phosphorylated, the presence of the uORF maintained translation of the L pORF, indicating that the uORF modulates L translation in response to cellular stress. To directly address the role of the L uAUG in virus replication, a recombinant EBOV was generated in which the L uAUG was mutated to UCG. Strikingly, mutating two nucleotides outside of previously-defined protein coding and cis-acting regulatory sequences attenuated virus growth to titers 10-100-fold lower than a wild-type virus in Vero and A549 cells. The mutant virus also exhibited decreased viral RNA synthesis as early as 6 hours post-infection and enhanced sensitivity to the stress inducer thapsigargin. Cumulatively, these data identify novel mechanisms by which EBOV regulates its polymerase expression, demonstrate their relevance to virus replication and identify a potential therapeutic target.

Genome-wide mapping of methylated adenine residues in pathogenic Escherichia coli using single-molecule real-time sequencing.

Single-molecule real-time (SMRT) DNA sequencing allows the systematic detection of chemical modifications such as methylation but has not previously been applied on a genome-wide scale. We used this approach to detect 49,311 putative 6-methyladenine (m6A) residues and 1,407 putative 5-methylcytosine (m5C) residues in the genome of a pathogenic Escherichia coli strain. We obtained strand-specific information for methylation sites and a quantitative assessment of the frequency of methylation at each modified position. We deduced the sequence motifs recognized by the methyltransferase enzymes present in this strain without prior knowledge of their specificity. Furthermore, we found that deletion of a phage-encoded methyltransferase-endonuclease (restriction-modification; RM) system induced global transcriptional changes and led to gene amplification, suggesting that the role of RM systems extends beyond protecting host genomes from foreign DNA.

Patterns and rates of exonic de novo mutations in autism spectrum disorders.

Autism spectrum disorders (ASD) are believed to have genetic and environmental origins, yet in only a modest fraction of individuals can specific causes be identified. To identify further genetic risk factors, here we assess the role of de novo mutations in ASD by sequencing the exomes of ASD cases and their parents (n = 175 trios). Fewer than half of the cases (46.3%) carry a missense or nonsense de novo variant, and the overall rate of mutation is only modestly higher than the expected rate. In contrast, the proteins encoded by genes that harboured de novo missense or nonsense mutations showed a higher degree of connectivity among themselves and to previous ASD genes as indexed by protein-protein interaction screens. The small increase in the rate of de novo events, when taken together with the protein interaction results, are consistent with an important but limited role for de novo point mutations in ASD, similar to that documented for de novo copy number variants. Genetic models incorporating these data indicate that most of the observed de novo events are unconnected to ASD; those that do confer risk are distributed across many genes and are incompletely penetrant (that is, not necessarily sufficient for disease). Our results support polygenic models in which spontaneous coding mutations in any of a large number of genes increases risk by 5- to 20-fold. Despite the challenge posed by such models, results from de novo events and a large parallel case-control study provide strong evidence in favour of CHD8 and KATNAL2 as genuine autism risk factors.

Identification and remediation of biases in the activity of RNA ligases in small-RNA deep sequencing.

Deep sequencing of small RNAs (sRNA-seq) is now the gold standard for small RNA profiling and discovery. Biases in sRNA-seq have been reported, but their etiology remains unidentified. Through a comprehensive series of sRNA-seq experiments, we establish that the predominant cause of the bias is the RNA ligases. We further demonstrate that RNA ligases have strong sequence-specific biases which distort the small RNA profiles considerably. We have devised a pooled adapter strategy to overcome this bias, and validated the method through data derived from microarray and qPCR. In light of our findings, published small RNA profiles, as well as barcoding strategies using adapter-end modifications, may need to be revisited. Importantly, by providing a wide spectrum of substrate for the ligase, the pooled-adapter strategy developed here provides a means to overcome issues of bias, and generate more accurate small RNA profiles.

Impaired carbohydrate digestion and transport and mucosal dysbiosis in the intestines of children with autism and gastrointestinal disturbances.

Gastrointestinal disturbances are commonly reported in children with autism, complicate clinical management, and may contribute to behavioral impairment. Reports of deficiencies in disaccharidase enzymatic activity and of beneficial responses to probiotic and dietary therapies led us to survey gene expression and the mucoepithelial microbiota in intestinal biopsies from children with autism and gastrointestinal disease and children with gastrointestinal disease alone. Ileal transcripts encoding disaccharidases and hexose transporters were deficient in children with autism, indicating impairment of the primary pathway for carbohydrate digestion and transport in enterocytes. Deficient expression of these enzymes and transporters was associated with expression of the intestinal transcription factor, CDX2. Metagenomic analysis of intestinal bacteria revealed compositional dysbiosis manifest as decreases in Bacteroidetes, increases in the ratio of Firmicutes to Bacteroidetes, and increases in Betaproteobacteria. Expression levels of disaccharidases and transporters were associated with the abundance of affected bacterial phylotypes. These results indicate a relationship between human intestinal gene expression and bacterial community structure and may provide insights into the pathophysiology of gastrointestinal disturbances in children with autism.

Molecular characterization of severe and mild cases of influenza A (H1N1) 2009 strain from Argentina.

While worldwide pandemic influenza A(H1N1) pdm case fatality rate (CFR) was 0.4%, Argentina's was 4.5%. A total of 34 strains from mild and severe cases were analyzed. A full genome sequencing was carried out on 26 of these, and a partial sequencing on the remaining eight. We observed no evidence that the high CFR can be attributed to direct virus changes. No evidence of re-assortment, mutations associated with resistance to antiviral drugs, or genetic drift that might contribute to virulence was observed. Although the mutation D225G associated with severity in the latest reports from the Ukraine and Norway is not observed among the Argentine strains, an amino acid change in the area (S206T) surrounding the HA receptor binding domain was observed, the same previously established worldwide.

Molecular characterization of severe and mild cases of influenza A (H1N1) 2009 strain from Argentina / Caracterización molecular de cepas de influenza A (H1N1) 2009 de casos leves y graves de la Argentina

While worldwide pandemic influenza A(H1N1) pdm case fatality rate (CFR) was 0.4%, Argentina's was 4.5%. A total of 34 strains from mild and severe cases were analyzed. A full genome sequencing was carried out on 26 of these, and a partial sequencing on the remaining eight. We observed no evidence that the high CFR can be attributed to direct virus changes. No evidence of re-assortment, mutations associated with resistance to antiviral drugs, or genetic drift that might contribute to virulence was observed. Although the mutation D225G associated with severity in the latest reports from the Ukraine and Norway is not observed among the Argentine strains, an amino acid change in the area (S206T) surrounding the HA receptor binding domain was observed, the same previously established worldwide.

Mientras que la tasa de letalidad (CFR) para (H1N1)pdm en todo el mundo era del 0.4%, en la Argentina la mortalidad observada fue de 4.5%. La secuenciación del genoma completo de 26 cepas de virus argentinos de influenza A (H1N1)pdm de casos leves y graves y de 8 cepas secuenciadas parcialmente no mostró evidencia de que la elevada tasa de letalidad se pueda atribuir directamente a cambios en el virus. No se encontraron hallazgos de recombinación, de mutaciones asociadas con la resistencia a los medicamentos antivirales ni de variaciones genéticas que puedan contribuir a la virulencia observada. Si bien la mutación D225G asociada con la gravedad, comunicada en informes procedentes de Ucrania y Noruega, no se ha encontrado en las cepas argentinas estudiadas, se ha observado un cambio aminoacídico en la región (S206T) en torno al dominio del sitio de unión al receptor en la HA, el mismo hallado en cepas distribuidas alrededor del mundo.