CHEMOKINES IN SEASONAL ALLERGIC RHINITIS

Monocyte chemotactic and activating factor/monocyte chemoattractant pr otein-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 histamin e release from basophils. We questioned whether a relationship exists between the levels of these chemokines and various inflammatory mediat ors released from mast cells, eosinophils, and basophils as assessed i n nasal secretions obtained from patients during the allergy season an d out of season. Samples were assessed Sor MCAF/MCP-1, RANTES, MIP-1 a lpha, IL-8, histamine, tryptase and eosinophil cationic protein (ECP) in three subject groups: subjects with allergic rhinitis (n = 18), ato pic subjects without rhinitis (n = 9), and healthy individuals (n = 6) . Statistically significant differences were apparent only in the subj ects 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 d ecreased 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 sympt omatic 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 f rom 6.3 +/- 1.5 to 89 +/- 15.5 ng/ml (p < 0.001), ECP increased from 2 0.6 +/- 6.4 to 237.1 +/- 50.2 ng/ml (p < 0.001), and tryptase increase d 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 rh initis, contributing to the attraction of the proinflammatory cells an d mediator release, which might be very important during the late phas e of the allergic reaction. Furthermore, the ratio of certain chemokin es, such as MCAF/MCP-1 and IL-8 may reflect the magnitude of the react ion, as does the presence of histamine and ECP.