Allergic rhinitis to ragweed pollen: I. Reassessment of the effects of immunotherapy on cellular and humoral responses

This work presents a double-blind, placebo-controlled study of 27 patients with allergic rhinitis to ragweed who received preseasonal desensitization immunotherapy [IT] with alum-precipitated aqueous ragweed extracts. We reassessed the following parameters in relation to clinical responses: clinical scores, nasal reactivity to a provocative dose of ragweed causing a 75% fall in airflow rate (PD 75 ), ragweed IgE and IgG, and ragweed-induced basophil histamine release (BHR). First, the nasal PD 75 correlated with the severity of nasal symptoms ( p p 75 ( p p p p r =0.80; p p 75 ; r =0.64; p