For instance, neurotoxic reactive A1 astrocytes can be induced by activated microglia 31, astrocytes remove cell debris when microglial phagocytic activity is impaired 32, and microglia can be reprogrammed by astrocyte-derived interleukin-3 (IL-3) to ameliorate the pathology of Alzheimer's disease 33. This evidence concerns the gene IL3 and early-onset autosomal dominant Alzheimer disease.