These findings together with monocyte derived macrophages/microglia morphology and increased TNF-α immunoreactivity in a few mononuclear cells of unknown origin in the anterior horn in ALS support the idea that monocyte derived macrophages/microglia at end-stages of ALS have cytotoxic properties [25, 34, 35, 37]. This evidence concerns the gene TNF and amyotrophic lateral sclerosis.