To investigate the expression of serum amyloid beta-protein (Aβ)₁-42 in children with lead poisoning and its relationship with the blood lead level.

Totally 84 cases of children with lead poisoning were enrolled and divided into three groups according to the blood lead levels: the mild group (n = 40), the moderate group (n = 26) and the severe group (n = 18). Meanwhile, 28 healthy children were selected as the control group. Five trace elements (including the blood lead level) were determined by the atomic absorption method; serum levels of Aβ_1-42 were tested by enzyme-linked immunosorbent assay. The intelligence scale was to assess children patients' intelligence. After sodium dimercaptosulphonate treatment, the blood lead level and serum Aβ_1-42 concentration in children patients were also detected. The correlation was analyzed by Pearson correlation coefficients.

Before treatment, there were significant differences of the blood lead level and serum Aβ_1-42 concentration existing in four groups (F = 969.367, 136.678; all P < 0.05); as the level of lead poisoning increased, the blood lead concentration and serum Aβ_1-42 in each group increased as well. The blood lead level and serum Aβ_1-42 had positive correlation by Pearson correlation analysis (r = 0.893, P < 0.001). Before and after treatment, the blood lead levels in the mild [(219 ± 15) μg/L vs. (174 ± 15) μg/L], moderate [(289 ± 43) μg/L vs. (213 ± 43) μg/L], and severe [(489 ± 40) μg/L vs. (378 ± 44) μg/L] groups changed significantly (t = 15.295, 10.130, 9.237; all P < 0.05); the serum Aβ₁-42 concentrations in the mild [(326 ± 43) ng/L vs. (301 ± 33) ng/L], moderate [(392 ± 60) ng/L vs. (342 ± 63) ng/L], and severe [(515 ± 62) ng/L vs. (447 ± 54) ng/L] groups decreased significantly (t = 7.205, 4.350, 7.712; all P < 0.05). With the increased degree of lead poisoning in children patients at different ages, the score of the intelligence scale decreased significantly (all P < 0.05).

The serum Aβ_1-42 level can evaluate neurotoxicity caused by lead poisoning. It is an effective way combined with intelligence evaluation in older children.