Objective To explore the toxic effects of formaldehyde on immune system.
Methods Altogether 65 workers occupationally exposed to formaldehyde and 70 workers without occupational formaldehyde exposure were recruited into this study. Formaldehyde concentrations in the air were monitored. Serum complement C3, C4 and immunoglobulin IgA, IgG, IgM in venous blood of studied workers were determined using automatic analysis equipment.
Results The average air concentrations of formaldehyde was 0.43 mg/m3, the maximun concentration was 3.11 mg/m3, and the rate of exceeding the limit was 29.09%. There were significant differences between exposure group and control group in serum complement C3(0.99& #177; 0.31)and immunoglobulin IgM (1.16& #177;0.51). In particular, in the subgroup of workers more than 5 years exposure, their serum complement C3(0.85& #177;0.15), C4(0.20& #177;0.05)and immunoglobulin IgA(1.28& #177;0.57), IgM(0.90& #177;0.35)were significantly decreased(P < 0.01).
Conclusion Long term occupational exposure to formaldehyde may cause apparent immune suppression, and dose-effect response existed.
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