CXCL8 and myeloid sarcoma: In summary, we found lower serum levels of CXCL8 and CXCL10 in RRMS patients in comparison to controls, inverse association of concentration of CXCL8 with anti-EBNA IgG, and decreased peripheral production of CXCL8 in relapse, which may be explained by compensatory anti-inflammatory counter-regulation mechanisms in MS, and further studies are required to precisely define these mechanisms.