The immunologic response to tobacco antigens in smokers. III. Type III hypersensitivity skin reactions and specific serum precipitins to four different tobacco extracts in patients suffering from coronary artery disease.

In a population of 70 patients suffering from coronary heart disease (49 smokers and 21 non-smokers) intradermal tests and specific precipitation tests with four different extracts of tobacco were performed. Skin tests with tobacco extracts were positive in 41 smokers and 7 nonsmokers. In both groups the immediate and delayed type reactions were weak and of rather doubtful specificity, while the late type reaction was usually more frequent and stronger in smokers (in 14 patients it was positive with all preparations). Specific precipitins against tobacco antigens were found in the sera of 13 smokers but never in nonsmokers. The positive precipitation test correlated well with the positive late skin reactions to tobacco extracts. Such correlation with Ag 1 was observed in 9 out of 13 patients, with Ag II in four cases, with Ag IV and Ag V in 2 and 2 patients respectively. The coincidence of strongly positive late skin reactions and positive precipitation tests with tobacco extracts seems to indicate that tobacco allergy really exists and resembles, in a number of patients with coronary artery disease, type III hypersensitivity reactions to tobacco antigens. It is postulated that immune complexes of precipitins and tobacco antigens may be formed in some patients and initiate pathological processes in coronary arteries leading to their occlusion.