NRP1 and myeloid sarcoma: The receptors for these ligands (NP1 and NP2) are expressed by OPCs in and around all types of MS lesions, as well as by astrocytes and microglia/macrophage, suggesting that it is the differential expression of Sema3A and 3F in different MS lesions which confers different OPC recruitment patterns and their subsequent capacity to remyelinate (Fig. 11).