Abstract
The aim of this study was to determine the relative production of chemokines interleukin-8 (IL-8), regulated on activation, normal T-cell expressed and secreted (RANTES) and monocyte chemotactic protein-1 (MCP-1) by intrinsic and extrinsic asthmatics. Nine intrinsic asthmatics, 10 extrinsic asthmatics, five nonatopic and five atopic controls underwent bronchoalveolar lavage (BAL). Total BAL cells were cultured in the presence or absence of lipopolysaccharide. Chemokines were measured in BAL cell supernatants and in cell-free bronchoalveolar lavage fluid (BALF) by enzyme-linked immunoabsorbent assay (ELISA). BAL cell cytospins were stained immunohistochemically for chemokines. BAL cells from asthmatics produced more IL-8 than controls (statistically significant for extrinsic asthma). RANTES was elevated in the BAL cell supernatants of four out of nine intrinsic asthmatics as compared to nonatopic controls (not statistically significant). RANTES levels in the BAL cell supernatants of extrinsic asthmatics were all low. MCP-1 production by BAL cells was similar in all groups. Immunostaining of BAL cell cytospins showed the macrophage to be the predominant positive-staining cell type and correlated well with supernatant data. Measurement of chemokines in BALF showed significantly elevated IL-8 in intrinsic asthma compared to nonatopic controls, but no increase in extrinsic asthmatics relative to atopic control RANTES was elevated in three out of nine BALFs from intrinsic asthmatics compared with nonatopic controls (not statistically significant). MCP-1 was not elevated above control levels in BALF of either asthma group. These results suggest an up-regulation in the production of interleukin-8 and regulated on activation, normal T-cell expressed and secreted, but not monocyte chemotactic protein-1 (MCP-1), by macrophages in the bronchoalveolar lavage of asthmatic subjects. In addition, the data suggest that regulated on activation, normal T-cell, expressed and secreted, may be differentially produced by macrophages in atopic and nonatopic asthma.
