IL4 and Autoimmunity: Even though the different tolerogenic dendritic cell (tDC) populations used in clinical trials for autoimmunity thus far, including T1D, are mainly of the myeloid lineage (12–15), it has far from conclusively-demonstrated that they represent a completely-pure myeloid-derived lineage, following ex vivo generation, in the widely-used granulocyte-macrophage colony-stimulating factor (GM-CSF) + interleukin-4 (IL-4) cell culture medium (20).