RESPONSES OF ALVEOLAR MACROPHAGES TO POST-GULF-WAR AIRBORNE DUST FROMKUWAIT

The Kuwait oil fires of 1991 resulting from the Iraqi invasion created an unprecedented environmental pollution to which the population was exposed for a prolonged period. The impact of such pollution on human health, especially the respiratory system, needs to be adequately asse ssed, given the well known relationship between air pollution and resp iratory diseases. Alveolar macrophages (AM) are the main resident cell s in the bronchial lumen and are known to perform microbicidal and tum oricidal roles by releasing oxygen radicals and cytokines. The effects of the extracts and particles of the post oil fire airborne dust coll ected from air conditioner filters in the Ahmadi area of Kuwait in 199 1-1995 on the in vitro spontaneous and PMA-stimulated generation of su peroxide ions (O-2) from guinea pig AM and lipopolysaccharide (LPS)-st imulated tumor necrosis factor (TNF alpha) release from mouse AM were studied. Treatment of adherent AM with aqueous extract of the 1991 dus t (0.6-10 mg/mL) resulted in a dose-dependent inhibition of basal, as well as PMA-induced O-2 release. At lower concentrations, slight incre ases were seen. Fifty percent inhibition of O; release was achieved by extracts of 1-2.4 mg/mL of the dust and at 10 mg/mL the maximal inhib ition was 79-88%. At the same concentration range, the extract also in hibited the LPS-stimulated release of TNF alpha from mouse AM. These e ffects were more pronounced in the 1991 dust samples than in the 1992 and 1995 samples. No such effect was seen with the extract of silica ( SiO2) used as particulate control. All washed dust or SiO2 particulate s directly induced the release of both O-2 and TNF alpha from these ce lls. These results show that the post-oil fire airborne dust of Kuwait contained soluble pollutants that were capable of inhibiting the host defensive functions of the: AM and this may have possibly resulted in an increased susceptibility to respiratory infections and neoplasms a mong the exposed population. (C) 1998 Elsevier Science Ltd.