Toll-like receptor 5 agonist flagellin reduces influenza A virus replication independently of type I interferon and interleukin 22 and improves antiviral efficacy of oseltamivir.

Influenza infections remain a burden on health care systems despite vaccination programs and marketed antiviral drugs. Immunomodulation through activation of innate sensors could represent innovative approaches to fight the flu. This study evaluated the ability of flagellin, agonist of Toll-like receptor 5 (TLR5), to control the replication of influenza A virus (IAV) in mice. First, we showed that systemic or intranasal administration of flagellin activated transcription of anti-viral genes in lung tissue. Prophylactic and therapeutic flagellin administration resulted in decreased levels of viral RNA and infectious virus in the lungs of H3N2 IAV-infected mice. The effect of the flagellin on viral replication was also observed in Ifnar-/- and Il22-/- IAV-infected mice, suggesting a mechanism independent of type I interferon and interleukin 22 signaling. In addition, a combination therapy associating the neuraminidase inhibitor oseltamivir and flagellin was more effective than standalone treatments in reducing pulmonary viral replication. Thus, this study highlights the therapeutic potential of the flagellin to control the replication of the influenza virus.

A one-step immune-chromatographic Helicobacter pylori stool antigen test for children was quick, consistent, reliable and specific.

AIM: This French study assessed a quick, noninvasive, immuno-chromatographic, Helicobacter pylori (H. pylori) stool antigen test for detecting infections in children. METHODS: We enrolled 158 children, with a median age of 8.5 years (range eight months to 17 years), with digestive symptoms suggesting upper gastrointestinal tract disease. Upper digestive endoscopy was performed with gastric biopsy specimens for histology, a rapid urease test, culture test and quantitative real-time polymerase chain reaction. The H. pylori stool antigen test was performed twice for each child and the results were compared to the reference method. RESULTS: The reference methods showed that 23 (14.6%) of the 158 children tested were H. pylori positive. The H. pylori stool antigen test showed 91.3% sensitivity, with a 95% confidence interval (95% CI) of 86.9-95.6 and 97% specificity (95% CI 94.3-99.6), 30.84 positive likelihood ratio and 0.09 negative likelihood ratio. The test accuracy was 96.2% (95% CI 93.2-99.1). The two blinded independent observers produced identical H. pylori stool antigen test results and the Kappa coefficient for the H. pylori stool antigen test was one. CONCLUSION: The H. pylori stool antigen test was found to be a consistent, reliable, quick and specific test for detecting the H. pylori infection in children.

A Toll-Like Receptor 5 Agonist Improves the Efficacy of Antibiotics in Treatment of Primary and Influenza Virus-Associated Pneumococcal Mouse Infections.

Prophylactic intranasal administration of the Toll-like receptor 5 (TLR5) agonist flagellin protects mice against respiratory pathogenic bacteria. We hypothesized that TLR5-mediated stimulation of lung immunity might improve the therapeutic index of antibiotics for the treatment of Streptococcus pneumoniae respiratory infections in mice. Intranasal administration of flagellin was combined with either oral administration of amoxicillin or intraperitoneal injection of trimethoprim-sulfamethoxazole to treat S. pneumoniae-infected animals. Compared with standalone treatments, the combination of antibiotic and flagellin resulted in a lower bacterial load in the lungs and greater protection against S. pneumoniae dissemination and was associated with an early increase in neutrophil infiltration in the airways. The antibiotic-flagellin combination treatment was, however, not associated with any exacerbation of inflammation. Moreover, combination treatment was more efficacious than standalone antibiotic treatments in the context of post-influenza virus pneumococcal infection. Lastly, TLR5 signaling was shown to be mandatory for the efficacy of the combined antibacterial therapy. This report is the first to show that combining antibiotic treatment with the stimulation of mucosal innate immunity is a potent antibacterial strategy against pneumonia.

Confirmation of a founder effect in a Northern European population of a new ß-globin variant: HBB:c.23_26dup (codons 8/9 (+AGAA)).

ß-Thalassemia is a genetic disease caused by a defect in the production of the ß-like globin chain. More than 200 known different variants can lead to the disease and are mainly found in populations that have been exposed to malaria parasites. We recently described a duplication of four nucleotides in the first exon of ß-globin gene in several families of patients living in Nord-Pas-de-Calais (France). Using the genotypes at 12 microsatellite markers surrounding the ß-globin gene of four unrelated variant carriers plus an additional one recently discovered, we found that they shared a common haplotype indicating a founder effect that was estimated to have taken place 225 years ago (nine generations). In order to determine whether this variant arose in this region of Northern Europe or was introduced by migrants from regions of the world where thalassemia is endemic, we genotyped the first 4 unrelated variant carriers and 32 controls from Nord-Pas-de-Calais for 97 European ancestry informative markers (EAIMs). Using these EAIMs and comparing with population reference panels, we demonstrated that the variant carriers were very similar to the controls and were closer to North European populations than to South European or Middle-East populations. Rare ß-thalassemia variants have already been described in patients sampled in non-endemic regions, but it is the first proof of a founder effect in Northern Europe.

Identification of a new mutation on the beta-globin gene: codons 8/9 (+AGAA); GAG.AAG.TCT(Glu-Lys-Ser)>GAG. AAAGAAG, in a patient from the north of France with a phenotype of beta-thalassemia minor.

A 37-year-old man presented a slight debility. The hemogram showed a phenotype of beta-thalassemia minor: Hb (13.1 g/dL), mean corpuscular volume (MCV) (62 fL) with low mean corpuscular hemoglobin (MCH) (20.8 pg), associated with a high level of Hb A(2) of 5.3%. The serum ferritin level was 1,072 ng/mL. The sequencing of the mutated fragment revealed a duplication of four bases of codons 7/8 involving a shift in the open reading frame starting from codon 9 with a TGA stop codon at codon 23: codons 7/8/9 (+AGAA); GAG.AAG.TCT(Gly-Lys-Ser)>GAG.AAAGAAG. The human hemoglobin (Hb) instability tests were negative. The patient did not present the high iron Fe (HFE) mutation (C282Y, H63D). The same mutation was found in five other unrelated families (representing a total of 23 patients). All of their ancestors came from the north of France. This mutation has not been described before and could have its origins in the native populations of Northern France.