The levels of serum interleukin-1 beta (IL-1 beta), interleukin-2 (IL-2), tumor necrosis factor alpha (TNF-alpha) and gamma-interferon (gamma-IFN) were assessed in the workers who were occupationally exposed to lead and cadmium. The a values were compared with the age-matched control group. Blood lead and cadmium levels were significantly raised. Our findings suggest that chronic lead and cadmium exposure in humans resulted in significant suppression of the serum IL-1 beta level, but did not alter IL-2 and TNF-alpha levels. The gamma-IFN level was also reduced in lead workers. In contrast, a significant enhancement was observed in the cadmium-exposed group. We conclude from these results that lead and cadmium exposure at chronically high level may affect some cytokine levels in humans. (C) 1997 Elsevier Science Ireland Ltd.