Chronic inflammation is responsible for auto-immune, and other, diseases. In pathogenic inflammatory diseases, high levels of immune cells (macrophages, neutrophils, and TH1 cells) migrate from the blood to the tissue over a prolonged period of time. Most articles recently published on this subject focus on inhibiting TH1 migration. Yet, TH1 cells do not directly cause tissue damage. What cells are activated by TH1 cytokines, and what do these cells do to cause damage?