In vivo nasal challenge with diesel exhaust particles enhances expression of the CC chemokines rantes, MIP-1 alpha, and MCP-3 in humans

Diesel exhaust particles (DEP) enhance allergic inflammation by increasing in vivo IgE and cytokine production in the human upper respiratory mucosa. CC chemokines have been shown to play an important role in inflammation. We examined whether DEP could alter the production of CC chemokines by cells residing in the human nasal mucosa. At both 6 and 24 h following intranasal DEP challenge, the levels of nasal RANTES, MIP-1 alpha, and MCP-3 were sig nificantly elevated compared to baseline. In contrast, DEP did not enhance levels of Eotaxin at any time, demonstrating that the action of DEP was not simply a global effect on all CC chemokines. Challenge with saline resulte d in no significant change in expression of any chemokine at any time. Chal lenge with DEP also resulted in an increase in total cell counts in nasal l avage fluids. Increases in lymphocyte, monocyte/macrophage, and neutrophil cells were observed but there was no change in eosinophil cell numbers. In contrast, there was a significant enhancement of ECP protein levels in wash es performed 6 to 24 h after DEP challenge. Elevated specific nasal chemoki ne expression following exposure to DEP likely participates in the inflamma tion, cellular infiltration, and increase in IgE observed in the absence of allergen. (C) 2000 Academic Press.