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Med. Pr. 2002;53(3)

The impact of lead and cadmium on the immune system

Wpływ ołowiu i kadmu na funkcje układu immunologicznego

Anna Skoczyńska, Rafał Poręba, Adrian Sieradzki, Ryszard Andrzejak, Urszula Sieradzka

Abstract

A long-lasting exposure to lead and cadmium may cause changes in the immune response. Until now only a few reports have addressed this problem. At present, the direct immunotoxicity of heavy metals is the subject of extensive studies, especially oninvitro models. Heavy metals may regulate the immune response of the body at its different stages, modifying early and late inflammatory reactions, among others through changing the number of circulating B and T lymphocytes, NK cells and immunologicalmemory cells. Some authors show that lead and cadmium stimulate the production of cytokines and IgE antibodies, which can be the reason for the increased number of atopic diseases in populations exposed to these two metals. Clinical tests in patients occupationally exposed to lead revealed the diminished number of B and T lymphocytes, and a considerable decrease in the number of NK cells. Other authors noted the increased number of CD8⁺ lymphocytes, which play a pivotal role in cytotoxic response, and the decreased number of B lymphocytes together with the increased IgA levels in policemen of road services. In copper smelters some changes in humoral response can be detected, e.g. a lower production of IgA and IgG, predisposing them to infections and cancers. To elucidate the exact impact of heavy metals on the immunological response further investigations are required. The growing pollution of the environment by heavy metals probably contributes to the enhanced incidence of allergic diseases and cancers in urban populations. Our goal should be to identify the mechanisms responsible for the changes in the immunological response induced by lead and cadmium, so that it could be possible to reduce or minimize serious pathologies resulting from the exposure to these metals.

Key words

lead, cadmium, cytokines, immunological response