MPO and Parkinson disease: MPO is generally considered a myeloid specific gene with expression restricted to bone marrow myeloid precursors, but the human MPO (hMPO) gene can escape this restriction in some stress situations, such as in macrophages in cardiovascular disease [20,21,22,23,24,25], microglia, astrocytes and neurons in Alzheimer’s Disease (AD) [26,27,28] and in astrocytes and neurons in PD [29,30,31,32].