<qa>  What is the specificity of IL-5?Interleukin IL-5 is a cytokine specifically focused on the development, differentiation, recruitment, activation and survival of the eosinophil. The specificity of IL-5 has raised the possibility that blocking its activity, using humanized monoclonal antibodies, may be useful therapy for eosinophilic bronchitis. Such an antibody SB-240563 has been introduced for clinical trial. The investigators will compare its effect versus placebo in patients with prednisone-dependant symptomatic eosinophilic bronchitis with or without asthma before and after a reduction in prednisone dose to identify if it has a prednisone-sparing effect. 