ABSTRACT
We investigated whether exposure to low levels of benzene (geometric mean of exposures = 0.28-0.41 parts per million) results in perturbations of the hemopoietic system found in patients with myeloproliferative diseases. Erythroid (BFU-E) and granulocyte-monocyte (CFU-GM) colonies from peripheral blood were grown in methylcellulose with and without the addition of cytokines (erythropoietin and granulocyte-stimulating factor). Colony growth from 17 workers exposed to low levels of benzene was compared with 20 healthy control subjects. Exposed workers had significantly increased growth of autonomous BFU-E and unstimulated CFU-GM when compared with the control subjects. Unexposed smokers had increased colony growth without the addition of cytokines. Colony growth was not significantly different between the groups after the addition of cytokines. Workers exposed to low concentrations of benzene and unexposed smokers have increased cytokine-independent hematopoiesis.
