Interleukin 13 (IL-13) is a cytokine, which is secreted from a lot cell types, but mostly from Th2 cells, which participate in allergic inflammation and disorder. This way IL-13 has similarities with IL-4, but it is believed to be better in the physiologic changes caused by allergic inflammation in a lot of tissues.
IL-13 has anti-inflammatory ability. It inducts enzymes called Matrix MetalloProteinases. They are essential to provoke removal of exhausted parenchymal inflammatory cells into the airway lumen where happens the removal. IL-13 also makes those MMP participate in process that defends against excessive allergic inflammation that bias to asphyxiation.
Interleukin 13 makes changes in hematopoietic cells, but this aftermath is less significant than that of IL-4.