S100A9 and myeloid sarcoma: The numbers of T cells (CD3), cytotoxic T cells (CD8), B cells (CD20), plasma cells (CD138), microglia/macrophages (KiM1P), and early activated macrophages (MRP14) were quantified within MS lesions of different demyelinating stages and the normal-appearing white matter of LOMS and NOMS patients.