Chronic lung inflammation in victims of toxic gas leak at Bhopal

Bronchoalveolar lavage (BAL) studies in 20 patients at Bhopal, 1.3 +/- 0.4 yr and 2.7 +/- 0.6 yr after toxic gas exposure had revealed that the lower respiratory tract inflammation had progressed from initial macrophage alveolitis to macrophage-neutrophilic alveolitis. The interval between the two lavages was 1.4 +/- 0.6 yr. BAL studies in a new group of 24 patients 5.1 +/- 1.0 yr after exposure had confirmed chronic inflammation of the lower respiratory tract as evidenced by macrophage-neutrophilic alveolitis in these subjects as well. Clinical, radiographic and pulmonary function abnormalities were persistent in a proportion of subjects in both groups. Fibronectin (FN) levels were estimated in BAL fluid in 41 patients. Elevated FN levels were seen in 12 (29.3%) subjects and nine of these 12 had radiographic abnormalities. Severely exposed subjects (n = 30) had significantly higher BAL fibronectin levels compared to normal subjects and mild/moderately exposed subjects. Repeat FN estimations in BAL samples from 10 patients had revealed that five had abnormally high FN including three who had high FN on both occasions. The number of patients showing abnormal decline in pulmonary function was higher in patients with elevated FN than in patients with normal FN. Thus, persisting clinical, roentgenographic and ventilatory abnormalities, as well as macrophage-neutrophilic alveolitis along with abnormally elevated FN levels in a proportion of subjects, suggest the possibility that lung fibrosis can occur in subjects exposed to toxic gas at Bhopal.