Mycoplasma pneumoniae infection exacerbates asthma in children and may play a role in the pathogenesis of chronic asthma. Because the airway epithelium is a preferential site for M. pneumoniae infection and a major source of the chemokine regulated on activation, normal T cells expressed and secreted (RANTES) and transforming growth factor (TGF)-beta1, we postulated that this microorganism may contribute to the disease by inducing these mediators through direct interaction with airway epithelial cells. We investigated the effects of M. pneumoniae on RANTES and TGF-beta1 production in primary cultures of normal human bronchial epithelial (NHBE) cells and small airway epithelial (SAEC) cells. Both cell types were permissive to M. pneumoniae infection in vitro, but their responses were different. TGF-beta1 was induced at higher levels in NHBE than in SAEC cultures, whereas RANTES was induced in SAEC cultures but not in NHBE cultures. These effects were attenuated by erythromycin and dexamethasone. In vitro adherence assays further indicated that the effects of erythromycin were mediated through its antimicrobial action, resulting in diminished adherence of the pathogen, whereas the effects of dexamethasone did not appear to be by inhibition of adherence. These results suggest that M. pneumoniae infection may contribute to the pathogenesis of chronic asthma at different levels of the airways, by inducing TGF-beta1 in large airways and the chemokine RANTES in small airways.
The aim of this study was to investigate ventilation in mild to moderate asthmatic patients and age-matched controls using hyperpolarized (HP) Xenon magnetic resonance imaging (MRI) and correlate findings with pulmonary function tests (PFTs).
IgE plays an important role in allergic asthma. We hypothesized that reducing IgE in the airway mucosa would reduce airway inflammation. Forty-five patients with mild to moderate persistent asthma with sputum eosinophilia of 2% or more were treated with humanized monoclonal antibody against IgE (omalizumab) (n = 22) or placebo (n = 23) for 16 weeks. Outcomes included inflammatory cells in induced sputum and bronchial biopsies, and methacholine responsiveness. Treatment with omalizumab resulted in marked reduction of serum IgE and a reduction of IgE+ cells in the airway mucosa. The mean percentage sputum eosinophil count decreased significantly (p
Systemically bioavailable leukotriene receptor antagonists (LTRAs) can reduce the essential components of allergic inflammation in allergic rhinitis (AR) and asthma by blocking cysteinyl leukotriene (CysLT) activity, resulting in a wide range of clinical effects. CysLTs, mediators, and modulators in the pathophysiology of asthma and AR are a key target for therapy because they modulate production of hemopoietic progenitor cells, survival and recruitment of eosinophils to inflamed tissue, activity of cytokines and chemokines, quantity of exhaled NO, smooth-muscle contraction, and proliferation of fibroblasts. The mechanism of action of LTRAs leads to their effects on systemic allergic inflammatory processes.