CD33 and myeloid sarcoma: Given that the role of CD33 rs3865444 in MS susceptibility was reported only in a single paper [19], we decided to perform a case-control study to evaluate the impact of this SNP on MS risk in the Slovak population and further examine whether its association with the disease is affected by the HLA-DRB1*15:01 allele as the single strongest MS genetic risk factor [40,41].