 2. Subjects who show a pattern of early progression and failure to resolve LowLow group have clinical evidence of steroid insensitivity compared to those with slow progression NormalLow group. They also have in vitro evidence of steroid resistance compared to the NormalLow or NormalNormal groups. This pattern of obstruction may be due to irreversible changes consistent with airway remodeling and inflammation that are relatively refractory to steroid therapy. 