Infusion of stimulated platelets restores pulmonary eosinophil and lymphocyte recruitment in sensitized mice depleted of platelets. Sham- and OVA-sensitized mice were exposed to allergen, and BAL fluid was obtained 24 hours after the third day of challenge and analyzed for eosinophil (A) and lymphocyte (B) numbers. In some groups, mice were rendered thrombocytopenic with the administration of busulfan. Selected groups of thrombocytopenic mice were intravenously administered WPs, FUSPs, or FSPs. (A, inset) Dose-response curve of platelet depletion compared with eosinophil recruitment. n = 4-6 animals per group. Data are expressed as mean ± SEM. ^*P < .05; ^**P < .01.