title: Serum immunoglobulins and lymphocyte subset distributions in children and adults living in communities assessed for lead and cadmium exposure.
abstract: This study assessed the impact of environmental cadmium and lead exposure on the immune system of more than 2000 children and adults. Serum immunoglobulins [immunoglobulins (Ig) A, G, and M] and peripheral blood lymphocyte phenotypes (T cells, B cells, NK cells, and CD4/CD8 subsets) were measured in a total of 2041 children and adults who lived either in sites with elevated soil levels of cadmium and lead (n = 1561) or in comparison communities (n = 480). The blood lead and urine cadmium levels of participants were somewhat higher than national averages. Mean blood lead levels were 7 microg/dl for participants aged 6-35 mo; 6 microg/dl for participants aged 36-71 mo, 4 microg/dl for participants aged 6-15 yr; and 4.3 microg/dl for participants aged 16-75 yr. Multivariate analysis indicated no marked differences in any of the immune marker distributions attributed to lead for adults or children over 3 yr of age. However, in children under age 3, increased blood lead levels, principally those over 15 microg/dl, were associated with increases in IgA, IgG, IgM, and circulating B lymphocytes. Among adults, urine cadmium levels over 1.5 microg/g were associated with higher levels of IgA and circulating B lymphocytes. No evidence of immunosuppression was noted. The findings of potential immunologic effects at lead levels > 15 microg/dl in young children and at urine cadmium levels > 1.5 microg/g in adults are interesting, but too few participants had these high levels to delineate a threshold. Therefore, we find these results intriguing, but requiring confirmation in populations with higher exposure levels.
authors.affiliation: Health Investigations Branch, Division of Health Studies, Agency for Toxic Substances and Disease Registry, Atlanta, Georgia 30333, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Sarasua
authors.forename: R F
authors.initials: RF
authors.lastname: Vogt
authors.forename: L O
authors.initials: LO
authors.lastname: Henderson
authors.forename: P A
authors.initials: PA
authors.lastname: Jones
authors.forename: J A
authors.initials: JA
authors.lastname: Lybarger
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001402:B-Lymphocytes / Q000187:drug effects; D002104:Cadmium / Q000633:toxicity*; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure; D006801:Humans; D007136:Immunoglobulins / Q000097:blood*; D007223:Infant; D007854:Lead / Q000633:toxicity*; D016131:Lymphocyte Subsets / Q000187:drug effects*; D008875:Middle Aged
chemical_list: D007136:Immunoglobulins; D002104:Cadmium; D007854:Lead