S100A9 and myeloid sarcoma: Increased abundance of a myeloid cell subset in peripheral blood of early MS patients with a phenotype corresponding to classical monocytes with pro-inflammatory markers (markers associated with M1 macrophage polarization, CD86, CD64, CD32), regulatory markers (markers related to M2 macrophage polarization, CD206, CD209, PD- L1) and a high expression of S100A9 have been recently shown by Colloume et al.