Phosphorylated Signal transducer and activator of transcription 6 (STAT6) dimers translocate to the nucleus and activate the transcription of several genes. In experimental models, targeted gene disruption of STAT6 inhibited airway hyperresponsiveness, airway inflammation, and fibrosis (Blease et al. 2002). STAT6 promotes transcription of the extracellular proteins C-C motif chemokine 11 (CCL11, Eotaxin) (Matsukura et al. 1999), Ig epsilon chain C region (IGHE) (Stütz & Woisetschlager 1999), Ig gamma-1 chain C region (IGHG1) (Warren et al. 1999) and Ig gamma-4 chain C region (IGHG4) (Hebenstreit et al. 2006).