Effect of lead exposure on serum immunoglobulins and reactive nitrogen and oxygen intermediate.

Metal toxicants may affect immune regulation with an increased incidence of infectious diseases, cancer or autoimmune diseases. Lead is the leading environmental toxin among heavy metals and has aroused concern, as continuous low-level exposure leads to a variety of health problems. We compared serum immunoglobulins (Ig) and reactive oxygen and nitrogen intermediates (super oxide and nitric oxide (NO)) in culture supernatant of lead-exposed (blood lead; Pb-B > 10 microg/dL) individuals with that of unexposed healthy controls (blood lead < 10 microg/dL). The serum IgA level was significantly increased in lead-exposed individuals in comparison to controls (182 +/- 53 versus 138 +/- 52 mg/dL; P < 0.05). Furthermore, lipopolysaccharide-induced NO production by mouse macrophage cells, RAW 264.7, showed significant suppression (P < 0.05) after treatment with lead acetate (100 ppm). This study suggested that lead could modulate the immune system by targeting the humoral as well as innate immune cells.