IL18 and amyotrophic lateral sclerosis: IL-6 and IL-18 have been found upregulated in the CSF of ALS patients,70 and in a large progression study, IL-18 (but not IL-6) was consistently elevated across progression in the CSF of ALS patients.16 TNF-α is a 17 kDa major pro-inflammatory cytokine secreted by activated macrophages and is involved in the induction of cytokine production, phagocyte cell activation, activation or expression of adhesion molecules, and growth stimulation.188 TNF-α is reported upregulated in the CSF,72 and in serum,71 but not consistently associated with disease state.