Occupational-type exposure tests and bronchoalveolar lavage analyses in two patients with byssinosis and two asymptomatic cotton workers.

Two workers suffering from stage III byssinosis and claiming for compensation were examined. Bronchial obstruction was present in one case. MEF25-75 values were significantly reduced and bronchial hyperreactivity was present in both subjects. Occupational-type exposure tests with cotton dust resulted in significant decreases in arterial oxygen pressure for more than 2 h and were associated with an obstructive ventilation pattern in one of the patients. Prolonged hypoxemia which is not paralleled by lung function changes is probably typical for byssinosis patients since we have never seen this in inhalative challenge tests with various environmental antigens and other occupational substances including flour dust. No specific IgE or IgG antibodies could be detected. In the two patients a hitherto unknown significant increase in CD23+ lymphocytes and granulocytosis were detected by bronchoalveolar lavage (BAL). Corresponding investigations in two cotton workers without any evidence of byssinosis revealed neither lung function changes after the exposure test nor striking BAL findings. Our results demonstrate the diagnostic value of specific challenge tests and BAL investigations in patients suffering from byssinosis, which is often difficult to diagnose.