[A study on the immunologic effects in workers exposed to low levels of toluene-diisocyanate (TDI)]

Forty-three workers exposed to low levels of toluene diisocyanate (TDI) during the process of producing polyurethane forms were examined immunologically for IgG, A, M, and E and serum enzyme activities such as serum angiotensin converting enzyme (SACE), serum lysozyme (SLZM) and glycylproline dipeptidyl aminopeptidase (GP-DAP). Air concentration of TDI was annually measured in various places of work during the past five years from 1979 to 1983. The results obtained in the present study were as follows. 1. The air concentration of TDI at all places of work was below the permissible concentration level of 0.02 ppm throughout the study period. 2. Subjective symptoms and abnormal findings on chest X-ray considered directly related to TDI exposure were not observed. 3. No remarkable abnormal findings in blood cell counts and in serum biochemical studies could be seen in any of the workers. 4. The serum IgG levels in workers directly exposed to TDI were significantly higher (p less than 0.05) than those in workers indirectly exposed to TDI and in non-exposed workers. 5. In the study of serum enzymatic activity, SLZM activity in workers exposed directly to TDI was significantly higher (p less than 0.01) than those in workers indirectly exposed to TDI and in non-exposed workers.