INTERLEUKIN-1-ALPHA AND HEMATOLOGICAL EXAMINATION IN MECHANICS EXPOSED TO LOW BENZENE CONCENTRATIONS

Object: To examine the hypothesis of Rent and Kalf relative to the inv olvement of interleukin 1 alpha (IL-1 alpha) in the development of ane mia in benzene-exposed workers. According to this hypothesis, benzene inhibits the cleavage of the IL-1 alpha precursor (proIL-1 alpha) to m ature IL-1 alpha and the lack of this cytokine is responsible for benz ene-induced bone marrow suppression. This inhibition of the processing of proIL-1 alpha. is attributed to an inhibition of calpain. Method: Selection of a population of mechanics exposed to low levels of benzen e from fuels, assessment of usual exposure and lifetime exposure durat ion, and measurements of concentrations of workplace-air benzene and u rinary benzene metabolites. Determination of IL-1 alpha. concentration s was done by a whole-blood assay after lipopolysaccharide stimulation and a hematological examination was carried out. Statistical analysis consid ered several possible confounding factors, particularly smokin g and drinking habits. Design: Cross-sectional study. Results: The lev el of exposure of the mechanics to benzene from fuels was mostly well below 1 ppm. IL-1 alpha production was not decreased in mechanics expo sed to benzene from fuels, and no correlation between IL-1 alpha conce ntrations and red blood cell counts appeared. With the exception of a slight decrease in red blood cell counts in mechanics, no hint of a to xic effect of exposure on hematological parameters was found. Conclusi ons: The hypothesis of Renz and Kalf could not be confirmed. Although the low level exposure of the study population and methodological fact ors are possible explanations, it cannot be excluded that the hypothes is of Rent and Kalf is not generalizable to benzene-exposed humans. Pr esently, one cannot advise the measurement of IL-1 alpha production fo r biological effect monitoring of workers exposed to low concentration s of benzene.