1. Determination of the effect of anti-IgE therapy on FcεRI expression and basophil responses. We will first confirm that anti-IgE therapy causes a reduction in the FcεRI level on basophils and then analyze whether this occurs at a transcriptional level. We will confirm that the therapy causes a reduction in basophil response to cross-linkage of FcεRI and then determine whether it also affects basophil response induced by non-IgE stimuli. The effect of the therapy on the FcεRI level on skin mast cells will also be investigated.