Skin damage immune response. Computer artwork showing the body's immune response to pathogens (red dots) entering through a skin wound (upper centre). A blood vessel full of red blood cells is shown at bottom. The presence of the pathogenic foreign bodies has stimulated neutrophil white blood cells (pink) to migrate through the blood system to the affected area and out of the blood vessel towards the pathogens. Here they are releasing hypochlorous acid (HClO, small circles) to kill the pathogens.