Iraq Dust is Respirable Sharp Metal-Laden and Induces Lung Inflammation with Fibrosis in Mice via IL-2 Upregulation and Depletion of Regulatory T Cells

摘要

Soldiers returning from Iraq have reported respiratory symptoms. Lung biopsies show constrictive bronchiolitis and vascular remodeling with polarizable crystals. We hypothesized that ground surface dust may be a contributing factor to Iraq Afghanistan War Lung Injury (IAW-LI) and analyzed soil grab samples from Camp Victory, Iraq to determine if particle sizes are respirable. Samples contain particles 2.5 micron in size and have sharp edges. Trace metals (including titanium), calcium and silicon are present. Mice with airway instillation of dust have polarizable crystals and septate inflammation. CD4+CD25+FOXP3+ regulatory T cells are decreased in spleen and thymus from mice exposed to dust. IL-2 is elevated from bronchoalveolar lavage taken from dust-exposed mice. Respirable Iraq dust leads to lung inflammation in mice similar to that seen in patients, particularly regarding polarizable crystals which, appear to be titanium.