Effects of low level lead on the immune function of occupationally exposed workers / 中国职业医学

ABSTRACT

OBJECTIVE: To explore the effect of long-term low-level lead load on the immune function of occupationally exposed workers. METHODS: The convenient sampling method was used to select 57 lead-exposed workers as the observation group.These workers had the blood lead level of ≥300 μg/L and <400 μg/L.They worked in a battery plant from 2009 to 2018. Another 61 none-lead exposed logistical personnel with blood lead level of <100 μg/L were selected as the control group. The blood lead levels and immune function indicators were detected in these 2 groups, including serum immunoglobulin(Ig)G, IgA, IgM, complement(C) 3, C4, C-reactive protein(CRP), tumor necrosis factor alpha(TNF-α) level, blood intermediate cell(MID) count and MID ratio(MID%).The abnormal rates of the above immune indexes were calculated. RESULTS: The median blood lead level in the observation group was 338 μg/L. The levels of IgA(M 2.3 vs 1.9 g/L), C3 [(10.8 ± 1.7) vs(10.1±1.5) mg/L] and C4(M 2.6 vs 2.3 mg/L) of observation group decrease(P<0.05), the abnormal rate of IgG increased(1.6% vs 14.0%, P<0.05), compared with the control group. The other immune indexes of these two groups were compared, and the differences showed no statistical significance(P>0.05). Blood lead level was negatively correlated with C3 level and positively correlated with TNF-α level(Spearman correlation coefficients were-0.20, 0.19, P<0.05). CONCLUSION: Low level lead might have an impact on the immune system of lead-exposed workers.