The investigators hypothesize that the increase in asthma severity in obese patients is, at least in part, related to a defective number or function of regulatory T cells (Tregs). That is in the obese asthmatic subject a defective Treg profile would augment the inflammation of asthma (a synergistic effect). Alternatively, that Treg dysfunction in obesity might affect asthma independently (an additive effect). To test these hypotheses, the investigators plan to conduct an observational controlled study to compare Treg profile in obese and normal-weight individuals with and without asthma. This is an exploratory study to investigate the following: 1. To determine whether Treg number and function differs between obese and normal-weight individuals with and without asthma. 2. To determine whether serum leptin levels differ between obese and normal-weight individuals with and without asthma.

To study whether the immune response as directed by regulatory T cells is different between obese asthmatics, normal weight asthmatics and healthy controls.