RESUMO
This study included forty-three male workers from eight gasoline filling stations and eleven unexposed controls of comparable age. The study revealed significantly increased plasma levels of TNF-alpha in exposed workers compared with the controls which correlated with duration index of exposure as well as urinary phenol excretion representing a biological monitor of benzene exposure. TNF-alpha could be derived from bone marrow cells reflecting hematotoxicity or kidney tissues and reflecting nephrotoxicity. The decreased RBCs sialic acid seems to reflect the associated hemolytic effect of benzene. Meanwhile, increased urinary sialic acid besides enhanced urinary excretion of tubular enzymes seemed to reflect nephrotoxicity affecting the glomerular filter and proximal renal tubules manifested also by increased albumin excretion. The marked correlations observed between these indices and duration index of exposure suggested a common source of origin. The results proved that those workers were greatly affected by benzene so, they should be examined periodically at least by routine blood picture and urine analysis as well as by simple determination of sialic acid. The period of exposure should also be decreased