Myalgic encephalomyelitis, also referred to as chronic fatigue syndrome (ME/CFS), is a debilitating condition with unknown etiology that is characterized by excessive and persistent fatigue with physical or mental exertion, often accompanied by flu-like symptoms, and not relieved by rest. Previous clinical studies suggest that infections caused by intracellular pathogens, such as Epstein-Barr virus, may elicit ME/CFS. Therefore, predisposition to the development of ME/CFS may be associated with an impairment of the immune system.
Hepatitis is an inflammation of the liver caused most commonly by hepatitis viruses. Cytotoxic T cells have essential roles in patients with viral hepatitis. Virus-specific cytotoxic T cells can recognize viral antigens of infected liver cells in collaboration with T helper cells. Despite this function in viral hepatitis, the cytotoxic T cell response is nearly undetectable in patients with chronic hepatitis B or C infections.
Autoimmune disorders develop when the body’s immune system does not distinguish between the body’s own cells and antigens. The destruction by the immune system of normal tissues is the basis of autoimmune diseases. The search for effective treatments or cures for autoimmune disorders depends on understanding the factors involved in immune cell function.