Innate and adaptive immunity in amyotrophic lateral sclerosis: Evidence of complement activation

►Complement immunoreactivity is significantly higher in ALS than control tissue. ►More activated microglia are found in slow than rapid progressing ALS patients. ►Influx of adaptive immune cells is observed in ALS spinal cord and motor cortex ►More dendritic cells are found in rapid than slow progressing ALS patients. ►Based on our findings we propose a positive feedback loop driven by C1q.