Histamine and Serotonin Stimulate Eotaxin Production by a Human Lung Fibroblast Cell Line

Histamine and serotonin are important inflammatory mediators in the pathophysiology of asthma, and asthmatic patients have higher plasma histamine and serotonin levels than nonasthmatic control subjects. Eotaxin, a potent eosinophil-specific chemotactic factor, is increased in the lower respiratory tract of allergic patients. Recently, lung fibroblasts have been reported to produce eotaxin and are suggested to be the major cellular source of eotaxin. We postulated that lung fibroblasts might release eotaxin in response to histamine or serotonin. To test this hypothesis, we evaluated the potential of histamine or serotonin to induce the release of eotaxin by the human fetal lung fibroblast cell line, HFL-1. HFL-1 released eotaxin in response to histamine and serotonin in a dose- and time-dependent manner (p < 0.05). Histamine or serotonin treatment of HFL-1 augmented the expression of eotaxin mRNA. Eosinophil chemotactic activity by HFL-1 supernatant fluids was inhibited by anti-human eotaxin-neutralizing antibody. These findings lead to the hypothesis that lung-fibroblast-derived eotaxin may in part be responsible for the eosinophil infiltration observed in allergic disease of the airways.