Pig farmers have signs of bronchial inflammation and increased numbers of lymphocytes and neutrophils in BAL fluid.

The purpose of this study was to investigate whether pig farmers had inflammation of the bronchial mucosa and activation of bronchoalveolar lavage (BAL) cells. Pig farmers are exposed to high dust levels and have a prevalence of work-related respiratory symptoms. Bronchoscopy and BAL were performed in 27 young large-scale pig farmers, who had never smoked. Fifty three lifetime nonsmoking healthy students participated as controls. All farmers and controls had normal lung function (forced expiratory volume in one second (FEV1) 109 and 105% predicted respectively. Estimation of macroscopic signs of inflammation in the bronchi (erythema, oedema, secretion and friability) showed that pig farmers had significantly increased signs of inflammation. The median score was 3 (range 0-6) compared to a median score of 0 (range 0-3) in controls. More pig farmers than controls (41 versus 25%) had a positive histamine challenge (provocative dose producing a 20% fall in FEV1 (PC20) < or = 32 mg.mL-1) but the difference was not significant. The cell concentration in BAL fluid was identical in the two groups. Pig farmers had a significantly increased percentage of lymphocytes (median 7, range 1-27 versus median 2, range 0-7) and neutrophils (median 2, range 0-30 versus median 1, range 0-4) compared to controls. Spontaneous migration (19.8 versus 5.5 microns) and chemotaxis (62.6 versus 11.2 microns) was significantly increased in pig farmers compared to controls. After stimulation with zymosan and phorbol myristrate acetate (PMA), the reactive oxygen radical generation of purified alveolar macrophages was also significantly increased in pig farmers. Lifetime nonsmoking pig farmers with normal lung function have macroscopic signs of bronchial inflammation and an increased number of neutrophils in bronchoalveolar lavage. Their alveolar macrophages showed biological signs of activation. The inflammation of pig farmers bronchi may be early signs of bronchitis.