Stimulating the body’s immune defenses against a tumor can reduce or eliminate it. However, in cancer immunotherapy, when immune checkpoint inhibitors unleash the immune system, severe autoimmunity can result. A hematological technique, extracorporeal photopheresis (ECP), could offer a solution. It reduces the therapy-induced inflammation without altering antitumor immunity. According to scientists at the Universities of Basel and Freiburg, the key lies in adiponectin, a hormone produced by fatty tissue.