ALPHA(1)-ANTITRYPSIN PHENOTYPES IN PATIENTS WITH CRYPTOGENIC FIBROSING ALVEOLITIS - A CASE-CONTROL STUDY

Cryptogenic fibrosing alveolitis (CFA) is an interstitial lung disease , which by definition is of unknown aetiology, Recent evidence has sug gested that smoking and occupational exposure to dusts may be environm ental risk factors for the disease, but there has been little research into potential host risk factors, One previous study has suggested th at the prevalence of abnormal alpha(1)-antitrypsin phenotypes may be i ncreased in patients with CFA. Since alpha(1)-antitrypsin is important in regulating inflammation within the lung in response to environment al exposures, such abnormalities may be of aetiological importance in this disease, We have compared the alpha(1)-antitrypsin phenotypes of 189 patients with CFA with 189 age-, sex-, and community-matched contr ols. This sample size was sufficient to provide more than 95% power to detect an odds ratio (OR) of 2.5, Alpha(1)-antitrypsin phenotype was established by isoelectric focusing, and the prevalence of abnormal ph enotypes in cases and controls was compared by conditional logistic re gression, Personal smoking histories were obtained by postal questionn aire, The prevalence of abnormal alpha(1)-antitrypsin phenotypes was s imilar in cases and controls (12.7 versus 15.3%; OR 0.88; 95% confiden ce interval 0.49-1.57; p=0.66), No interaction was found between the p resence of abnormal alpha(1)-antitrypsin phenotypes and a history of s moking, We conclude that cryptogenic fibrosing alveolitis is not assoc iated with abnormal alpha(1)-antitrypsin phenotypes.