Association Between Circulating Plasmacytoid Dendritic Cell Percentage and Blood Lead Levels in Children

Lead (Pb) exposure is known to cause T helper 1 (Th1) to T helper 2 (Th2) shift in the immune response. The mechanism responsible for these effects is unclear. Plasmacytoid dendritic cells (pDCs) are known as the principal secretor of type 1 interferons (IFNs), which have a stimulatory effect on Th1 differentiation. However, no previous study has explored the effect of Pb on pDCs. Thus, the present study was conducted to explore the correlation between circulating pDC count, serum IFNα (pan) levels, and blood lead levels (BLLs) in children environmentally exposed to Pb. A total of 82 school-going children were recruited from government and private schools in Jodhpur. BLL, pDC percentages, and serum IFNα (pan) levels were estimated by atomic absorption spectrometry, flow cytometry, and ELISA, respectively, in 82 samples. The participants were divided as per BLL quartiles into 4 groups: (A) BLL < 3 μg/dL (n = 21), (B) BLL = 3-4.08 μg/dL (n = 20), (C) BLL = 4.08-6.17 μg/dL (n = 20), and (D) BLL > 6.17 μg/dL (n = 21). Only in category D, pDC percentages showed a significant positive correlation with BLL (Spearman's R = 0.5). Therefore, this preliminary data suggests that BLL might modulate pDC levels in a dose-dependent manner.