SERPINB4 and asthma: To clarify the underlying mechanism of how IL-4 and/or IL-13 generates asthma-like phenotypes by acting on airway epithelial cells, we studied IL-4/IL-13–inducible genes in those cells using a DNA microarray and found that SCCA1 and SCCA2 are downstream molecules of IL-4/IL-13 (Figure 3) [18].