(University of Bonn) The chemotactic protein CCL17 attracts immune cells to where they are currently needed. Doctors have long known: A high level of this substance in the body indicates an allergic reaction. A team of scientists led by the University of Bonn has now discovered a completely new function: CCL17 also influences signal transmission in the brain. There may even be a molecular link to autism. The results have now been published in the journal Glia.