Cytokines related to three major types of cell-mediated immunity in short- and long-term exposures to lead compounds

Abstract

Many investigators have posited on the significant influence of lead on the immune system function. However, available data on this topic are not conclusive. Therefore, a study was undertaken to examine associations between lead exposure and levels of cytokines related to the T-helper (T)-1, T2, and T17 types of immune response in humans. For these analyses, three population groups were examined: the first consisted of male workers exposed to lead for a short period of time (36-44 days); the second included male workers chronically exposed to lead (13 ± 10 years); and a control group that was composed of male administrative workers with blood lead levels (BLL) < 10 μg/dl. BLL were determined for all study subjects. Thereafter, serum samples were analyzed for the levels of interleukin (IL)-2 (IL-2), IL-4, IL-5, IL-12, IL-13, IL-17A, and interferon (IFN)-γ using a multi-analyte system. The results indicated that the levels of IFNγ IL-2, IL-12 (related to T1 cells), IL-4, IL-5, IL-13 (related to T2 cells), and IL-17A (related to T17 cells) did not change after a short-term exposure to lead (compared to baseline). However, the levels of all of these cytokines were significantly higher in workers chronically exposed to lead than in the controls by 82%, 32%, 81%, 22%, 70%, 42%, and 17% (IFNγ, IL-2, IL-12, IL-4, IL-5, IL-13, IL-17A, respectively). From these studies, we conclude that in humans, a short-term exposure to lead does not affect levels of cytokines related to the T1-, T2-, and T17-mediated immune responses, while chronic exposure modifies their levels. Taken together, these modifications do not evidence an ability of lead to promote specifically one type of immune response in an exposed host.

The influence of occupational chronic lead exposure on the levels of selected pro-inflammatory cytokines and angiogenic factors

“…In our previous study, the influence of lead on the other member of the MIP-1 family (MIP-1) was not observed in chronically lead-exposed workers. 30 Similarly, the present study did not show significant difference between MIP-1a levels in the examined groups.…”

Immunological effects of occupational exposure to lead

“…In a recent study conducted on three population groups with different period of exposure, the authors highlighted significant higher levels of IFN-γ, IL-2 and IL-12 in workers chronically exposed to lead (13±10 years) compared to workers exposed to lead for 36 to 44 days and to a group of not exposed subjects (68).…”

Relevance of Essential Trace Elements in Nutrition and Drinking Water for Human Health and Autoimmune Disease Risk

“…According to Fenga et al (2017), lead enhances Th2 cell development, affecting Th1 cell proliferation and leading to high levels of IgE and inflammatory cytokines [86]. However, other authors have demonstrated that there are not changes in cytokine levels related to the Th1-, Th2-and Th17-mediated immune responses after short-term exposure to lead, in contrast to chronic exposure [87]. Therefore, lead alters Th cell functions, increasing the susceptibility to autoimmune diseases and hypersensitivity.…”