Cluster of Differentiation 123 (CD123), also known as Interleukin-3 Receptor, plays an important role in regulating the immune system by transmitting interleukin-3 signals, thereby promoting proliferation and differentiation of hematopoietic stem cells. CD123 has been noted to be expressed by myeloid precursors, macrophages, dendritic cells, mast cells, basophils, and megakaryocytes.