Immune cells, pictured here in bright teal, occupy the epithelial layers between the skin surface and its stem cells and act as a system regulator. (Photo by: Fuchs lab) Researchers have discovered a regulatory circuit connecting the skin surface to stem cells via Langerhans immune cells (LCs) that act as immune system regulators. They published their results in Science. This circuit acts like a “rheostat” that continuously fine-tunes the stem cells’ response to the environme