Given that platelets have been reported in extravascular compartments in allergic animal models (19) and have been found in the BAL fluid of patients with asthma (2), the aims of the present study were, first, to examine the compartmental location of platelets and quantify them in the airways of subjects with asthma and, second, to assess the active recruitment of platelets in a mouse model of allergic inflammation and the influence of platelet CCR3, CCR4, and CXCR4 chemokine receptors. This evidence concerns the gene CCR4 and asthma.