Effect of cigarette smoking on prevalence of summer-type hypersensitivity pneumonitis caused by Trichosporon cutaneum.

We investigated the effect of cigarette smoking on the prevalence of summer-type hypersensitivity pneumonitis (SHP) caused by Trichosporon cutaneum. In the adult family members of SHP patients, we found that 27 of 41 (65.9%) nonsmokers were SHP patients, compared with 3 of 11 (27.3%) smokers (p less than .05). Also, the prevalence of anti-T. cutaneum antibody was significantly lower in the smokers (p less than .05). A questionnaire provided to 209 SHP patients revealed that the smoking rates of male and female SHP patients were significantly lower (p less than .01) than rates in the normal Japanese population. However, no difference was found in serum anti-T. cutaneum antibody activities or the bronchoalveolar lavage lymphocyte phenotypes for smoking and nonsmoking SHP patients. It was concluded that cigarette smoking had a suppressive effect on the outbreak of SHP, but smoking caused no further suppression after the disease was established.