Asthma is a chronic airway inflammation which involves the interplay of different types of inflammatory cells and cytokines in the airway. The presence of systemic inflammation and oxidative stress in asthma suggests that it has a propensity to develop cardiovascular morbidity. Recent small scale studies have demonstrated that asthma severity may be associated with both airway and systemic inflammation. The investigators' study aims at linking asthma severity to airway and systemic inflammation, and subsequently to cardiovascular morbidity if a significant association of the aforementioned is present. The role of airway inflammation in contribution to systemic inflammation , and potential interaction between these two conditions will also be studied.