Asthma Exacerbations: Pathogenesis, Prevention, and Treatment.

Guideline-based management of asthma focuses on disease severity and choosing the appropriate medical therapy to control symptoms and reduce the risk of exacerbations. However, irrespective of asthma severity and often despite optimal medical therapy, patients may experience acute exacerbations of symptoms and a loss of disease control. Asthma exacerbations are most commonly triggered by viral respiratory infections, particularly with human rhinovirus. Given the importance of these events to asthma morbidity and health care costs, we will review common inciting factors for asthma exacerbations and approaches to prevent and treat these events.

Corticosteroid therapy and airflow obstruction influence the bronchial microbiome, which is distinct from that of bronchoalveolar lavage in asthmatic airways.

BACKGROUND: The lung has a diverse microbiome that is modest in biomass. This microbiome differs in asthmatic patients compared with control subjects, but the effects of clinical characteristics on the microbial community composition and structure are not clear. OBJECTIVES: We examined whether the composition and structure of the lower airway microbiome correlated with clinical characteristics of chronic persistent asthma, including airflow obstruction, use of corticosteroid medications, and presence of airway eosinophilia. METHODS: DNA was extracted from endobronchial brushings and bronchoalveolar lavage fluid collected from 39 asthmatic patients and 19 control subjects, along with negative control samples. 16S rRNA V4 amplicon sequencing was used to compare the relative abundance of bacterial genera with clinical characteristics. RESULTS: Differential feature selection analysis revealed significant differences in microbial diversity between brush and lavage samples from asthmatic patients and control subjects. Lactobacillus, Pseudomonas, and Rickettsia species were significantly enriched in samples from asthmatic patients, whereas Prevotella, Streptococcus, and Veillonella species were enriched in brush samples from control subjects. Generalized linear models on brush samples demonstrated oral corticosteroid use as an important factor affecting the relative abundance of the taxa that were significantly enriched in asthmatic patients. In addition, bacterial α-diversity in brush samples from asthmatic patients was correlated with FEV1 and the proportion of lavage eosinophils. CONCLUSION: The diversity and composition of the bronchial airway microbiome of asthmatic patients is distinct from that of nonasthmatic control subjects and influenced by worsening airflow obstruction and corticosteroid use.

Investigational drugs for the treatment of allergic rhinitis.

INTRODUCTION: Allergic rhinitis is characterized by paroxysms of sneezing, rhinorrhea and nasal obstruction. Its prevalence is increasing in industrialized countries worldwide and imposes a significant economic burden as a result of reduced school performance, work productivity and medical expenses. Allergic rhinitis impairs the quality of life of those affected, and current treatment regimens are inadequate for those whose symptoms are severe or refractory to standard drug therapies. They mainly include symptom control with intranasal glucocorticoids, oral and intranasal antihistamines. AREAS COVERED: This article provides a review of the most current literature on research that has focused on improving the efficacy of current treatment regimens and developing new drugs. It also provides the reader with an improved understanding of the pathogenesis of allergic rhinitis, including the inflammatory mediators and cell types involved, which has led to novel treatment options that are under investigation. These new drugs aim to alter the immunologic response to allergens in order to achieve greater clinical efficacy. EXPERT OPINION: It is our opinion that despite developments in new therapies, a multidrug approach is vital for successful treatment of allergic rhinitis. Furthermore, immunotherapy in the form of sublingual immunotherapy is a promising additional therapeutic approach that will potentially make immunotherapy available to a wider selection of eligible patients with allergic rhinitis.