Chemokines in seasonal allergic rhinitis.

Monocyte chemotactic and activating factor/monocyte chemoattractant protein-1 (MCAF/MCP-1), RANTES, and macrophage inflammatory protein (MIP)-1 alpha are chemokines known to activate basophils (MCAF/RANTES) and eosinophils (RANTES/MIP-1 alpha). IL-8 inhibits MCAF-induced histamine release from basophils. We questioned whether a relationship exists between the levels of these chemokines and various inflammatory mediators released from mast cells, eosinophils, and basophils as assessed in nasal secretions obtained from patients during the allergy season and out of season. Samples were assessed for MCAF/MCP-1, RANTES, MIP-1 alpha, IL-8, histamine, tryptase and eosinophil cationic protein (ECP) in three subject groups: subjects with allergic rhinitis (n = 18), atopic subjects without rhinitis (n = 9), and healthy individuals (n = 6). Statistically significant differences were apparent only in the subjects with symptoms as follows. MCAF/MCP-1 increased during the season from 336 +/- 47 pg/ml to 829 +/- 137 pg/ml (p < 0.001), whereas IL-8 decreased from a baseline of 1932 +/- 335 pg/ml to 1070 +/- 202 pg/ml (p < 0.028). The ratio of IL-8 to MCAF/MCP-1 decreased during the symptomatic season from the baseline of 6.66 +/- 1.06 seen during winter to 1.3 +/- 0.22 during ragweed season (p < 0.001). Histamine increased from 6.3 +/- 1.5 to 89 +/- 15.5 ng/ml (p < 0.001), ECP increased from 20.6 +/- 6.4 to 237.1 +/- 50.2 ng/ml (p < 0.001), and tryptase increased from 2.34 +/- 0.6 to 9.7 +/- 2.3 U/ml (p < 0.001). Most samples did not have detectable quantities of MIP-1 alpha or RANTES. We also found a correlation between the level of MCAF/MCP-1 and IL-8 and the level of histamine or IL-8 and ECP. Our results suggest that the chemokines MCAF/MCP-1 and IL-8 may participate in the pathogenesis of allergic rhinitis, contributing to the attraction of the proinflammatory cells and mediator release, which might be very important during the late phase of the allergic reaction. Furthermore, the ratio of certain chemokines, such as MCAF/MCP-1 and IL-8 may reflect the magnitude of the reaction, as does the presence of histamine and ECP.