OCCUPATIONAL-TYPE EXPOSURE TESTS AND BRONCHOALVEOLAR LAVAGE ANALYSES IN 2 PATIENTS WITH BYSSINOSIS AND 2 ASYMPTOMATIC COTTON WORKERS

Two workers suffering from stage III byssinosis and claiming for compe nsation were examined. Bronchial obstruction was present in one case. MEF25-75 values were significantly reduced and bronchial hyperreactivi ty was present in both subjects. Occupational-type exposure tests with cotton dust resulted in significant decreases in arterial oxygen pres sure for more than 2 h and were associated with an obstructive ventila tion 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 detec ted. In the two patients a hitherto unknown significant increase in CD 23+ lymphocytes and granulocytosis were detected by bronchoalveolar la vage (BAL). Corresponding investigations in two cotton workers without any evidence of byssinosis revealed neither lung function changes aft er the exposure test nor striking BAL findings. Our results demonstrat e the diagnostic value of specific challenge tests and BAL investigati ons in patients suffering from byssinosis, which is often difficult to diagnose.