Clinical response to pandemic H1N1 influenza virus from a fatal and mild case in ferrets

Methods: Viral strains isolated from a patient showing mild disease-M (A/CastillaLaMancha/RR5661/2009) or from a fatal case-F (A/CastillaLaMancha/RR5911/2009), both without known comorbid conditions, were inoculated in two groups of ferrets and clinical and pathological conditions were analysed. Results: Mild to severe clinical symptoms were observed in animals from both groups. A clinical score distribution was applied in which ferrets with mild clinical signs were distributed on a non-severe group (NS) and ferrets with severe clinical signs on a severe group (S), regardless of the virus used in the infection. Animals on S showed a significant decrease in body weight compared to animals on NS at 4 to 7 days post-infection (dpi). Clinical progress correlated with histopathological findings. Concentrations of haptoglobin (Hp) and serum amyloid A (SAA) increased on both groups after 2 dpi. Clinically severe infected ferrets showed a stronger antibody response and higher viral titres after infection (p = 0.001). Conclusions: The severity in the progress of infection was independent from the virus used for infection suggesting that the host immune response was determinant in the outcome of the infection. The diversity observed in ferrets mimicked the variability found in the human population.The authors kindly thank Dr. Juan Ortín for his scientific contribution. This work was partially supported by Instituto de Salud Carlos III (Programa especial de investigación sobre la gripe pándemica GR09/0023, GR09/0040, GR09/0039), AGL2013-48923-C2-02 and CIBER de Enfermedades Infecciosa

Expression dynamics of innate immunity in influenza virus-infected swine

We would like to thank Dr. Jaime Maldonado and HIPRA, Spain for the A/swine/Spain/54008/2004 (H3N2) influenza virus; Dr. Dubovi and Cornell University for the A/Canine/NY/105447/08 (H3N8) influenza virus; Dr. Chambers and University of Kentucky for the A/Equine/OH/1/03 (H3N8) influenza virus; and Dr. Hon Ip and the US Geological Survey National Wildlife Health Center for the A/American black duck/Maine/44411-532/2008 (H3N8) and the A/Harbour Seal/New Hampshire/179629/2011 (H3N8) influenza viruses. The authors thank Sergio López, David Solanes and Francisco X. Abad for their help during the experimental infections as well as the personnel in Cat3 laboratories and animal house. The authors also wish to thank Dr. I. L. Archetti (IZSLER, Brescia, Italy) for the invaluable help in measuring some clinical immunology parameters, Dr. L. Fraile (UdL, Spain) for assistance in statistical analysis, Dr. J. Domínguez (INIA, Spain) for porcine antibodies, Dr. M. Gennari and Dr. M. Giunta (S.S. Genova, IZSPLV, Italy) for assistance in real-time PCR analyses. The skillful technical assistance of Mrs. C. Mantovani (IZSLER, Brescia, Italy) is also gratefully acknowledged. The research leading to these results has received funding from: the European Community's Seventh Framework Programme (FP7, 2007-2013), Research Infrastructures action, under the grant agreement No. FP7-228393 (NADIR project), and from the project AGL2010-22200-C02-01 of Spanish Ministry of Science and Innovation.Geological Survey National Wildlife Health Center/[u'duck/Maine/44411-532/2008', u'H3N8']The current circulating swine influenza virus (IV) subtypes in Europe (H1N1, H1N2, and H3N2) are associated with clinical outbreaks of disease. However, we showed that pigs could be susceptible to other IV strains that are able to cross the species barrier. In this work, we extended our investigations into whether different IV strains able to cross the species barrier might give rise to different innate immune responses that could be associated with pathological lesions. For this purpose, we used the same samples collected in a previous study of ours, in which healthy pigs had been infected with a H3N2 Swine IV and four different H3N8 IV strains circulating in different animal species. Pigs had been clinically inspected and four subjects/group were sacrificed at 3, 6, and 21 days post infection. In the present study, all groups but mock exhibited antibody responses to IV nucleoprotein protein. Pulmonary lesions and high-titered viral replication were observed in pigs infected with the swine-adapted virus. Interestingly, pigs infected with avian and seal H3N8 strains also showed moderate lesions and viral replication, whereas equine and canine IVs did not cause overt pathological signs, and replication was barely detectable. Swine IV infection induced interferon (IFN)-alpha and interleukin-6 responses in bronchoalveolar fluids (BALF) at day 3 post infection, as opposed to the other non-swine-adapted virus strains. However, IFN-alpha responses to the swine-adapted virus were not associated with an increase of the local, constitutive expression of IFN-alpha genes. Remarkably, the Equine strain gave rise to a Serum Amyloid A response in BALF despite little if any replication. Each virus strain could be associated with expression of cytokine genes and/or proteins after infection. These responses were observed well beyond the period of virus replication, suggesting a prolonged homeostatic imbalance of the innate immune system

Characterization in vitro and in vivo of a pandemic H1N1 influenza virus from a fatal case

Pandemic 2009 H1N1 (pH1N1) influenza viruses caused mild symptoms in most infected patients. However, a greater rate of severe disease was observed in healthy young adults and children without co-morbid conditions. Here we tested whether influenza strains displaying differential virulence could be present among circulating pH1N1 viruses. The biological properties and the genotype of viruses isolated from a patient showing mild disease (M) or from a fatal case (F), both without known co-morbid conditions were compared in vitro and in vivo. The F virus presented faster growth kinetics and stronger induction of cytokines than M virus in human alveolar lung epithelial cells. In the murine model in vivo, the F virus showed a stronger morbidity and mortality than M virus. Remarkably, a higher proportion of mice presenting infectious virus in the hearts, was found in F virus-infected animals. Altogether, the data indicate that strains of pH1N1 virus with enhanced pathogenicity circulated during the 2009 pandemic. In addition, examination of chemokine receptor 5 (CCR5) genotype, recently reported as involved in severe influenza virus disease, revealed that the F virus-infected patient was homozygous for the deleted form of CCR5 receptor (CCR5Δ32).Funding Statement: This work was supported by Instituto de Salud Carlos III (Programa especial de investigación sobre la gripe pándemica GR09/0023, GR09/0040, GR09/0039) and Ciber de Enfermedades Respiratorias. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.S

Prospective individual patient data meta-analysis of two randomized trials on convalescent plasma for COVID-19 outpatients

Data on convalescent plasma (CP) treatment in COVID-19 outpatients are scarce. We aimed to assess whether CP administered during the first week of symptoms reduced the disease progression or risk of hospitalization of outpatients. Two multicenter, double-blind randomized trials (NCT04621123, NCT04589949) were merged with data pooling starting when = 50 years and symptomatic for <= 7days were included. The intervention consisted of 200-300mL of CP with a predefined minimum level of antibodies. Primary endpoints were a 5-point disease severity scale and a composite of hospitalization or death by 28 days. Amongst the 797 patients included, 390 received CP and 392 placebo; they had a median age of 58 years, 1 comorbidity, 5 days symptoms and 93% had negative IgG antibody-test. Seventy-four patients were hospitalized, 6 required mechanical ventilation and 3 died. The odds ratio (OR) of CP for improved disease severity scale was 0.936 (credible interval (CI) 0.667-1.311); OR for hospitalization or death was 0.919 (CI 0.592-1.416). CP effect on hospital admission or death was largest in patients with <= 5 days of symptoms (OR 0.658, 95%CI 0.394-1.085). CP did not decrease the time to full symptom resolution

Pulmonary transcriptomic responses indicate a dual role of inflammation in pneumonia development and viral clearance during 2009 pandemic influenza infection

20 p.- 5 fig.- 1 tab.Background: The interaction between influenza virus and the host response to infection clearly plays an important role in determining the outcome of infection. While much is known on the participation of inflammation on the pathogenesis of severe A (H1N1) pandemic 09-influenza virus, its role in the course of non-fatal pneumonia has not been fully addressed.Methods: A systems biology approach was used to define gene expression profiles, histology and viral dynamics in the lungs of healthy immune-competent mice with pneumonia caused by a human influenza A (H1N1) pdm09 virus, which successfully resolved the infection.Results: Viral infection activated a marked pro-inflammatory response at the lung level paralleling the emergence of histological changes. Cellular immune response and cytokine signaling were the two signaling pathway categories more representative of our analysis. This transcriptome response was associated to viral clearance, and its resolution was accompanied by resolution of histopathology.Discussion: These findings suggest a dual role of pulmonary inflammation in viral clearance and development of pneumonia during non-fatal infection caused by the 2009 pandemic influenza virus. Understanding the dynamics of the host's transcriptomic and virological changes over the course of the infection caused by A (H1N1) pdm09 virus may help identifying the immune response profiles associated with an effective response against influenza virus.This work was supported by Instituto de Salud Carlos III: "Programa de Investigacion Comisionada en Gripe (GR09/0021) and Programa para favorecer la incorporacion de grupos de investigacion en las Instituciones del Sistema Nacional de Salud" (EMER07/050). This work was also supported by Biotechnology and Biological Sciences Research Council (BBSRC) grant (BBS/E/I/00002014). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewe

F virus is more pathogenic than M virus <i>in vivo</i>.

<p>Six mice were intranasally inoculated with 10⁶ PFU (50 µl) of either M or F influenza viruses or were mock infected with 50 µl of PBS. (A), Body weights were determined daily for 14 days and are depicted as the percentage of body weights at time of inoculation. Data show body weights mean of mice (n = 6). Error bar represent standard deviation. (B), Mice were monitored daily for survival for 14 days. Animals that lost 25% of its body weight were euthanized and counted as dead animals. For body weights, Student’s t-test was performed to determine the <i>P</i> value. <i>*P</i><0.05, <i>***P</i><0.001. For survival, statistical significance was assessed by a Logrank (Mantel-Cox) Test. <i>*P</i><0.05.</p

Histopathological signs of the lungs of the M and F-infected mice.

<p>Histopathological lesions (1: mild; 2: moderate; 3: severe). Numbers in blue (M virus) or red (F virus) highlight histopathological differences between both viruses.</p