ABSTRACT
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207 Effects of Pb on Humoral Immunity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 Effects of Pb on T Cell-Mediated Immunity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210 Effects of Pb on Myelomonocytic Cell Function . . . . . . . . . . . . . . . . . . . . . . . . . . 211 Effect of Pb on Host Resistance to Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214 Contribution of Pb Exposure to Hypersensitivity and Autoimmunity . . . . . . . . . . 216 Differences in Sensitivity Based on Age of Exposure . . . . . . . . . . . . . . . . . . . . . . 216 Summary and Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
Currently, the Centers for Disease Control and Prevention de nes an elevated blood lead (Pb) level, or threshold for intervention level, to be 10 µg/dL or greater in a child ≤ 6 years old. Blood Pb levels (BLL) have declined steadily since the late 1970s, but exposure to Pb remains a signi cant problem at the local level where it is more common among low-income children, urban children, and those living in older housing. The most recent National Health and Nutritional Examination Survey data indicate that the geometric mean BLL in American children has decreased to 2 µg/dL [1]. However, despite the continued lowering of BLLs nationally, complacency about adverse health effects of Pb is not warranted. According to recent CDC statistics, ~ 11.5% of children ≤6 years old have BLLs in excess of 10 µg/dL. The social and economic factors contributing to Pb exposure are well known and are re ected by a disproportionate percentage of African-American children (21.6%) versus non-Hispanic White children (8.9%) af icted by Pb poisoning. The main source of Pb exposure for children is deteriorating paint and paint dust found in antiquated housing. It is estimated that 42 million homes, most of them in inner city neighborhoods, contain Pb paint somewhere in the dwelling, and 1.8 million children live in homes where there is deteriorating paint [2]. Pb toxicity is an international public health issue; it affects children worldwide [3-7], and it has recently been realized that refugee children resettling within the United States are a particularly vulnerable [6].
