The nonspecific esterase activity in lymphocytes of workers occupationally exposed to benzene and its homologues.

Activity of nonspecific esterase (NE) was determined in peripheral blood lymphocytes from workers occupationally exposed to organic solvents containing benzene, toluene and xylene, using a semiquantitative histochemical method. The benzene, toluene and xylene concentration at the workplace of the subjects studied, was equal to 0-370 0-580 and 0-560 mg/cu. m, respectively. In subjects having a working time longer than 54 months a decreased count of lymphocytes showing presence of NE in intact lysosomes and increased count of cells with presence of this enzyme both in the partially destroyed lysosomes and in the cell cytoplasm was observed. The above phenomenon demonstrates the lysosome damage and consecutive replacing of the enzyme activity from the lysosome into the cytoplasm. Since there was a positive correlation between the exposure time and numbers of cells with damaged NE-positive lysosomes it may be suggested that the semiquantitative histochemical estimation of NE activity within the lymphocytes can be used for monitoring the toxic effect of benzene and its homologues on lymphocytes.