PATHOGENESIS OF ISOCYANATE-INDUCED ASTHMA

3 asthmatic patients, occupationally exposed to vapors of toluylene diisocyanate (TDI), responded with a moderate to strong elevation of airway resistance up to the 26th h after inhalation challenge by 0.006-0.02 ppm TDI. No changes in chest radiographs and in D(LCO) were found. In none of the patients' sera, isocyanate-specific antibodies could be detected by RAST and Ouchterlony test. Change of job resulted in one case in an immediate interruption of the asthmatic symptoms, whereas in 2 patients recovery was slow over a period of 3 to 8 months and not complete. Our investigations suggest a toxic effect of isocyanates, which depends on their concentrations, and an important pharmacological reaction; but, up to now, there were no signs of allergic mechanisms.