CCL13 and myeloid sarcoma: However, the only surface marker that differs significantly between patients with MS + CIS and SC + RIS is the HERV H3 Env on the nonclassical monocyte population, and HERV H3 Env only correlates significantly with the monocyte chemoattractant protein (MCP)‐4 ratio, which does not differ significantly between any of the five patient groups.