Interestingly, a significant correlation was found between the level of response to Amantadine and Pemoline -pharmacological treatments of fatigue- and the reduction in serum levels of interleukin 1-beta (IL-1β) and interleukin 6 (IL-6) in MS patients (Bertolone et al., 1993). This evidence concerns the gene IL6 and myeloid sarcoma.