IMMUNOLOGICAL FINDINGS AMONG LEAD-EXPOSED WORKERS

A comprehensive panel of immune parameters was evaluated among 145 lea d-exposed workers with a median blood lead level (BLL) of 39 mu g/dL ( range: 15-55 mu g/dL) and 84 unexposed workers. After adjusting for co variates, we found no major differences in the percentage of CD3+ cell s, CD4+ T cells, CD8+ T cells, B cells, or NK cells between lead-expos ed and unexposed workers, although the association between lead exposu re and the number of CD4+ T cells was modified by age. We also found n o differences between exposed and unexposed workers in serum immunoglo bulin levels, salivary IgA, C3 complement levels, or lymphoproliferati ve responses. However among exposed workers, the percentage and number of B cells were positively associated with current BLL, serum IgG was negatively associated with cumulative lead exposure, and the percenta ge and number of CD4+/CD45RA+ cells were positively associated with cu mulative lead exposure. We found no evidence of a marked immunotoxic e ffect of lead at the exposure levels studied, although some subtle dif ferences in immunologic parameters were noted. (C) 1998 Wiley-Liss, In c.