PRTN3 and cutaneous mastocytosis: In CM, neutrophil proteins in plasma [including neutrophil primary granule proteins, neutrophil elastase, myeloperoxidase and proteinase 3 (PRTN3)] are associated with disease (14) and it has been hypothesized that neutrophil products contribute to CM pathology, with elastase damaging the endothelium (77, 78), and inflammatory factors such as TNF [reviewed in (79)] and ROS [reviewed in (80)] increasing expression of the iRBC adhesion receptor, ICAM-1 (81) on endothelial cells to promote parasite adhesion.