Abstract
To assess the role of crystal size in the biologic response, we quantitated the generation of reactive oxygen metabolites in human polymorphonuclear leukocytes (PMNs) or mononuclear leukocytes (MNs) with a chemiluminescence assay using 6 alpha-alumina preparations with average diameters of 0.6, 0.8, 3.2, 7.5, 28 and 68 μm on the basis of equal weights (1 mg/ml), and also on the basis of surface areas (100 cm2/ml). On an equal weight alumina particles induced PMN chemiluminescence in the following order of magnitude: 3.2 μm > 7.5 μm, 0.8 μm > 0.6 μm > 28 μm, 68 μm. The particulates induced MN cbemiluminescence: 3.2 μm > 0.8 pm > 0.6 μm > 7.5 μm > 28 μm, 68 μm. On the basis of identical surface areas, alumina elicited PMN chemiluminescence: 3.2 μm > 7.5 μm, 0.8 μm > 0.6 μm, 28 μm, 68 μm. The particulates induced MN chemiluminescence: 3.2 μm > 0.8 μm > 0.6 pm, 7.5 μm > 28 μm, 68 μm. The maximal effect of particle size on the alumina-induced production of reactive oxygen metabolites by human leukocytes was seen at around 3 μm.