IL13 and chronic obstructive pulmonary disease: Importantly, van der Pouw Kraan et al.(29) revealed that human IL-13 gene was located ona chromosomal region associated with airway highreactivity that was a strong risk factor for COPD.Interestingly, a recent study of Grubek-Jaworska et al.(30) found no significant differences in the level of IL13between the COPD and asthma groups.