The nitroblue tetrazolium reduction test in workers exposed to benzene and its homologues.

In 106 workers aged 18 to 56 years, occupationally exposed to organic solvents of paints and varnishes containing benzene, toluene and xylene for 1 to 122 months, the spontaneous and the stimulated reduction of nitroblue tetrazolium (NBT) in neutrophils was estimated. In all the subjects studied, both the spontaneous and the stimulated reduction of NBT was increased. However, after longer occupational exposure to benzene and its homologues the stimulated NBT reduction decreases. The negative correlation between the number of NBT-positive stimulated neutrophils and the exposure time was noted. The stimulated NBT test may be of value for industrial health control in the estimation of the toxic effects of the above compounds on the neutrophil system.