CD68 and amyotrophic lateral sclerosis: In this study we show, by using immunochemical methods, that COX-2, CB2 and P2X7 immunoreactivity are localised mainly in activated microglial cells/macrophages in ALS and also MS cord, and that it is co-localised with the microglial cell/macrophage markers CD68, [26], and ferritin [27].