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PubMed2005

Decrease of CD4+ T-lymphocytes in children exposed to environmental lead.

The effects of environmental lead on the immune system of young children were assessed by determining the peripheral blood lymphocytes CD3+, CD4+, CD8+, B(CD19+) counts, and natural killer (CD16+CD56+) cells in 35 preschool children whose mean blood lead level was 140.6 microg/L. The results were compared to an age- and sex-matched control group with a mean blood lead level of 64.3 microg/L. Compared to the controls, a significant reduction in the percentage of CD4+ cells and a significant increase of CD8+ cells were seen in the high-lead group. The negative correlation between the percentage of CD4+ cells and blood lead levels was found to be significant (p<0.01). These results suggest that exposure to environmental lead might result in alterations in the immune function of young children.

Antigens, CD19↗

PubMed2004

Preschool children's lead levels in rural communities of Zhejiang province, China.

The aim of the study was to determine mean blood lead levels (BLLs) and prevalence of elevated BLLs among preschool children aged 3-6 years in Zhejian rural communities, China. Data were gathered by means of a questionnaire and blood lead analyses for 217 children who attended six randomly selected kindergartens. BLLs ranged from 25-437 microg/l. Arithmetic mean was 95 microg/l and standard deviation was 56 microg/l. BLLs of 63 samples (29.0%) were > or =100 microg/l. Children with BLLs > or =100 microg/l came from families with a higher proportion of their fathers or mothers working in conditions of potential exposure to lead, as compared to those with BLLs <100 microg/l (P < 0.01). A significantly higher proportion of children with BLLs > or =100 micro/l lived in buildings that were located near small industries, such as mechanics, furniture, or paint shop, as compared to those with BLLs <100 microg/l (P < 0.01). In conclusion, the data indicate that high levels of childhood lead exposures even prevail in rural communities and deserve authorities' attention. With the recent ban of leaded gasoline in China, emphasis should shift to other sources of exposure in children.

Child↗