IL5 and asthma: Interestingly, the master transcription factor for the differentiation and activation of the Th2 cell subset, i.e., GATA binding protein 3 (GATA3), was significantly less expressed in both asthma groups compared with healthy controls, while expression of interleukin 4 (IL-4), IL-5, and IL-13 were below the detection limit for all samples.