Xujing Xie

Immunogenicity and Safety of a Chemically Synthesized Divalent Group A Streptococcal Vaccine

Background Group A streptococcus (GAS) infections and poststreptococcal sequelae remain a health problem worldwide, which necessitates searching for an effective vaccine, while no licensed GAS vaccine is available. We have developed a divalent peptide vaccine composed of 84 amino acids to cover the main GAS serotypes (M1 and M12 streptococci) in China, and herein, we aimed to evaluate immunogenicity and safety of this vaccine. Methods Mice were immunized with the vaccine. ELISA, indirect bactericidal test, and immunofluorescent assay were used to study immunogenicity. GAS challenge assay was used to test the protective effect. Safety was tested by histopathological analysis. Results Immunized group mice (n=16) developed higher titer antibody after immunization than nonimmunized group mice (n=16) did. This antibody can deposit on the surface of GAS and promote killing of GAS, resulting in 93.1% decrease of M1 GAS and 89.5% of M12 GAS. When challenged with M1 and M12 streptococci, immunized group mice had a higher survival rate (87.5% and 75%) than nonimmunized group mice (37.5% and 25%). No autoimmune reactions were detected on organs of mice. Conclusion The results suggest that this vaccine shows fair immunogenicity and safety, which will lead our research on GAS vaccine into clinical trial.

The prognostic value of exercise-induced ventricular arrhythmias in patients with and without coronary artery disease: A meta-analysis

BACKGROUND Significance of exercise-induced ventricular arrhythmias (EIVAs) is controversial. This meta-analysis aimed to determine the prognostic value of EIVAs in patients with and without coronary artery disease (CAD). METHODS Relevant studies were searched on Pubmed though December, 2015. Pooled odds ratio (OR) of endpoints (all-cause death, cardiac death or cardiac events) for all included studies was calculated at first to explore the significance of EVIAs in unselected population. Then, sensitivity analysis based on CAD status of population was performed to determine ORs of endpoints in CAD population, non-CAD population and mixed population, respectively. RESULTS A total of 14 studies examining 23,002 patients were included, with 5 studies involved CAD population, 4 involved non-CAD population, and 5 involved mixed population (%CAD ranged from 51.2% to 76.8%). EIVAs in unselected population were associated with a pooled OR of 1.626 (95%CI 1.334 to 1.983, p<0.001) of endpoints when compared with those without EIVAs. Sensitivity analysis further indicated that pooled ORs of endpoints were 1.395 (95%CI 1.061 to 1.833, p=0.017) in CAD population, 1.933 (95%CI 1.567 to 2.384, p<0.001) in non-CAD population, and 1.402 (95%CI 1.198 to 1.640, p<0.001) in mixed population. Heterogeneous among studies was identified. Meta-regression analysis found that study quality, mean follow-up period, percentage of lost, percentage of diabetes were associated with ORs of endpoints. CONCLUSIONS EIVAs were associated with increased risk of worse outcomes, no matter the patients had CAD or not. However, more studies are required to confirm this finding due to the variation of current evidences.