CXCR4 and myeloid sarcoma: While on one side the present study shows an early pregnancy-induced up-regulation of the CxCR4, TNFAIP3, SOCS2, and NR4A2 transcripts in MS patients, on the other side data reveal a pregnancy-related down-regulation of the same genes, in healthy controls, as well as in MS patients after the achievement of a healthy gene expression profile.