Suppressor of cytokine signaling 3 (SOCS3) is central in negatively regulating signal transducer and activator of transcription (STAT) 3, STAT4, STAT1 and STAT5 signaling after stimulation with IL-6, IL-11, IL-27, etc. Kubo et al. found that SOCS3 mRNA expression is increased in eosinophils and CD4+ T cells in asthma and nonasthmatic eosinophilic bronchitis. This evidence concerns the gene STAT4 and asthma.