Pascolizumab (SB 240683) is a humanized anti-IL-4 mAb developed originally by GlaxoSmithKline and currently in development at Protein Design Laboratories, Inc. Pascolizumab blocks the interaction of IL-4 with its receptor, thereby inhibiting the early events of asthma, including TH2 cell differentiation, eosinophilia, and IgE up-regulation. This evidence concerns the gene IL4 and asthma.