Autoantibodies in Silicosis Patients: Silica-Induced Dysregulation of Autoimmunity

Silica particles cause silicosis (SIL) and represent one of the most typical environmental and occupational substances that induce autoimmune disorders among the exposed popu-lation. Anti-nuclear antibody (ANA), anti-Sjögren’s-syndrome-related antigen A (SS-A), anti-centromere protein B (CENP)-B, and anti-scleroderma (Scl)-70 autoantibodies were examined in SIL and compared with those in healthy volunteers (HV) and patients with systemic sclerosis (SSc). Individuals with SIL were prone to autoimmune diseases and some autoantibodies seemed to be important as an estimation of this condition. Anti-Fas autoan- tibody found in SIL was functionally capable of inducing apoptosis in Fas-expressing cells, and this may cause a decrease of regulatory T cells (Tregs) expressing Fas in SIL. Moreover, responder T cells (Tresps) in SIL seemed to be activated chronically and protected from Fas-mediated apoptosis. Thus, an imbalance of Tresps (dominant) and Tregs (less) occurred in SIL. All of these causes of SIL are ready to further develop autoimmune diseases.