Cytogenetic damage and cell-mediated immunity in pneumoconiosis.

The International Agency for Research on Cancer (IARC) determined that crystalline silica inhaled from occupational sources should be classified as carcinogenic to humans and upgraded it from group 2A to group 1. It has also been found that silicosis may be associated with cancer of various organs and with autoimmune diseases. We studied both the cytogenetic effects and the influence on cell-mediated immunity of mineral dust inhalation in patients with pneumoconiosis, including silicosis. The frequency of sister chromatid exchanges and micronucleus in the pneumoconiosis group were significantly higher than in the controls, suggesting a cytogenetic influence of the occupationally inhaled dust. Alterations in the immunoregulatory T cells were observed in the pneumoconiosis groups, suggesting that inhaled mineral dust may cause immunotoxic effects. Based on these findings, we can consider that cytogenetic damages and immunoregulatory abnormalities in pneumoconiosis patients may play a role in the pathogenesis of various cancers and autoimmune diseases associated with pneumoconiosis.