A mystery is why the injured and diseased CNS would ever produce a neurotoxic reactive astrocyte. Although A1s are not directly toxic to bacteria, they do secrete many classical complement cascade components that are expected to greatly enhance clearance of bacteria by the immune system. Similarly, future studies should address whether A1s can recognize and kill virally-infected neurons in order to prevent spread of CNS viral infections, and whether A1s might control CNS immune response by recruiting or killing specific infiltrating immune cell types. Whatever the answers, new drugs that prevent A1 formation, promote A1 reversion, or block the A1 neurotoxin, hold great potential to treat a variety of chronic neurological diseases and acute CNS injuries.
