ALTERED HUMAN MONOCYTE MACROPHAGE FUNCTION AFTER EXPOSURE TO DIESEL EXHAUST PARTICLES/

The relationship between immune defense mechanisms and environmental p ollutants has been a focus of intensive research during the last decad e. In animal experiments, diesel exhaust particles (DEP) have been sho wn to exert adjuvant effects on the IgE response against aeroantigens and to compromise broncho-pulmonary immune defense. Important target c ells are monocytes/alveolar macrophages which display the important fu nctions of phagocytosis, antigen-presentation and modulation of inflam matory processes. To further evaluate the influence of DEP upon these cells, we investigated whether exposure to suspended DEP would change the phagocytic capacity and the tumor necrosis factor alpha (TNF-alpha ) release of human peripheral monocytes/alveolar macrophages. Our resu lts demonstrated a dose-dependent reduction of phagocytosis (p < 0.001 ) and an additional increase of an ongoing TNF-alpha response (p < 0.0 05). These findings may help to link exposure to environmental polluta nts to such biologic effects as increased susceptibility to broncho-pu lmonary disease or facilitated sensitization against aeroallergens.