CXCL8 and amyotrophic lateral sclerosis: We measured their systemic inflammatory markers, serum Spp1, and cytokine levels (interferon‐γ, interleukin [IL]‐1β, IL‐6, IL‐8, IL‐10, tumor necrosis factor‐α, and IL‐17A), investigated correlations between Spp1 levels and clinical features, and evaluated ALS survival rates according to Spp1 levels.