Lymphocyte activation in silica-exposed workers

Int J Hyg Environ Health. Apr-May 2014;217(4-5):586-91. doi: 10.1016/j.ijheh.2013.11.002. Epub 2013 Nov 25.

Abstract

Exposure to silica dust has been examined as a possible risk factor for autoimmune diseases, including systemic sclerosis, rheumatoid arthritis, systemic lupus erythematosus and ANCA-associated vasculitis. However, the underlying cellular and molecular mechanisms resulting in the increased prevalence of autoimmunity remain elusive. To clarify these mechanisms, we studied various markers of immune activation in individuals occupationally exposed to silica dust, i.e., serum levels of soluble IL-2 receptor (sIL-2R), levels of IL-2, other pro- and anti-inflammatory cytokines and lymphoproliferation. Our results demonstrate that silica-exposed individuals present important alterations in their immune response when compared to controls, as shown by increased serum sIL-2R levels, decreased production of IL-2 and increased levels of the pro-inflammatory (IFN-γ, IL-1α, TNF-α, IL-6) as well as anti-inflammatory (IL-10 and TGF-β) cytokines. Furthermore, silica-exposed individuals presented enhanced lymphoproliferative responses. Our findings provide evidence that the maintenance of immune homeostasis may be disturbed in silica-exposed individuals, possibly resulting in autoimmune disorders.

Keywords: Autoimmunity; Cytokines; Interleukin-2; Lymphocytes; Silica; Soluble IL-2 receptor alpha.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Brazil
  • Cell Proliferation
  • Environmental Pollutants / toxicity*
  • Female
  • Humans
  • Interleukin-2 / metabolism
  • Leukocytes, Mononuclear / cytology
  • Leukocytes, Mononuclear / drug effects
  • Lymphocyte Activation*
  • Male
  • Middle Aged
  • Occupational Exposure*
  • Receptors, Interleukin-2 / blood
  • Silicon Dioxide / toxicity*

Substances

  • Environmental Pollutants
  • Interleukin-2
  • Receptors, Interleukin-2
  • Silicon Dioxide