SELP and myeloid sarcoma: We have previously shown that platelet-derived 5-HT and PAF (Table 1) boosts the differentiation of pathogenic Th1 and Th17 cells during the early stages of MS and EAE (Ponomarev, 2018), while at later stages of the disease, platelets become depleted in granule content but upregulate adhesion molecules such as CD62P to form aggregates with lymphocytes (Starossom et al., 2015).