EPO and myeloid sarcoma: Additionally, increased blood and cerebrospinal fluid levels of LIF (Mashayekhi & Salehi, 2011), IL-11 (Zhang et al., 2015), CNTF (Massaro et al., 1997) and IL-6 (Wullschleger et al., 2013) have been found in MS patients, thus raising the possibility of them affecting the response to EPO.