Association of the CAT-262C>T Polymorphism with Asthma in Smokers and the Nonemphysematous Phenotype of Chronic Obstructive Pulmonary Disease.

Background: Catalase (CAT) is a part of the active antioxidant defense system and has been studied with regard to its association with asthma and chronic obstructive pulmonary disease (COPD), which are heterogeneous obstructive pulmonary diseases characterized by chronic airway inflammation. We hypothesized that the CAT gene might be involved in the common pathogenesis underlying asthma and COPD.Objective: To evaluate the association of CAT polymorphisms with specific phenotypes of asthma and COPD to identify the common underlying pathophysiologic mechanisms of these 2 diseases.Methods: The -262C> T and -21A> T polymorphisms in the CAT gene were genotyped in 493 individuals with asthma, 265 with COPD, and 1,076 healthy controls. Asthmatic patients were categorized according to smoking status (smokers and nonsmokers) and age at onset (early onset and adult onset) as part of a casecontrol study. In patients with COPD, visual scoring (computed tomographic score) was assessed to determine emphysema severity, which was used to evaluate associations with CAT gene polymorphisms.Results: Overall, the -262C> T and -21A> T polymorphisms were not associated with asthma. However, the -262CT+TT genotype was significantly associated with adult-onset asthma in smokers (P = .005), and a significant interaction between smoking status and the effect of -262C> T genotype on asthma were observed (P = .01). In patients with COPD, this genotype was significantly associated with a low computed tomographic score (P = .03), which indicates a nonemphysematous type of COPD.Conclusion: The present study indicates that the CAT gene is involved in the common pathogenesis underlying adult-onset asthma in smokers and the nonemphysematous type of COPD. (C) 2014 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.