For example, interleukin 31 is derived from TH2 cells, macrophages, mast cells, and mast cells in atopic dermatitis lesions with higher interleukin 31 immunoreactivity than normal skin.33 Interleukin 23, secreted by dendritic cells and macrophages, has been documented to be an important cytokine to control inflammation in peripheral tissues. Here, IL31 is linked to atopic eczema.