A number of cytokines, including histamine-releasing factors (HRFs), have a role to play in
IgE-mediated asthma. However, the influence of HRF in allergic rhinitis without asthma
remains to be revealed. This article presents a double-blind, placebo-controlled study on the
role of HRF in ragweed-allergic rhinitis and its modulation by natural pollen exposure and
specific immunotherapy (IT). Twenty-seven patients allergic to ragweed were randomly
assigned to receive either preseasonal alum-precipitated aqueous extracts of ragweed or …