The role of metals in autoimmune vasculitis: epidemiological and pathogenic study

OFR.and IL-12 productionboth involved in the pathogenesis of vasculitis.from human phagocytic cells stimulated with an amorphousdiatomaceous earth.and a crystalline quartz. form of Si at the doses of 10 and 100 mg mly1 was evaluated. Results: Study I } a positive history of exposure to Si resulted in significantly more present in cases 14r31s45%.than in controls 14r58s24%, Ps0.04, ORs2.4. and no other significant exposure association was found including asbestos, mineral oil, formaldehyde, diesel and welding fumes, grain and wood dust, leather, solvents, fungicides, bitumen, lead and paint.. Study II } past TBC infection was significantly more present in patients with vasculitis12r45s26%.than in controls 4r45s8%, P-0.05.. Study III } ANCA was present in 2r64 exposed peoplevs. 0r65 controls, PsNS.and 0r16 patients with TBC. Study IV } both amorphous and crystalline Si forms represented a stimulus for OFR and IL-12 production, but quartz resulted as a greater inductor. Conclusions: We conclude that Si exposure might be a risk factor for ANCA-associated vasculitis, possibly enhancing endothelial damage by phagocyte generation of oxygen free radicals and Th1 differentiation by an excessive IL-12 phagocyte production. Frequency of TBC was significantly higher in vasculitis patients. ANCA was not frequent in the preliminary examination of people with previous professional exposure or patients with TBC, but the number of samples evaluated is too small to allow conclusions. Q 2000 Elsevier Science B.V. All rights reserved.