Environmental Risk Factors for the Anti-synthetase Syndrome

Background: * Like other complex diseases, autoimmune diseases are the result of numerous causes, including genetic and environmental factors. Some researchers believe that people who are susceptible to autoimmune disorders develop them when the body reacts to environmental or other factors by creating white blood cells that attack the body s own tissues, which then progresses to autoimmune diseases. These immune-triggered disorders can overlap with one another to some extent, but most autoimmune diseases have certain distinct triggers. * The autoimmune disorder myositis weakens the muscles and may cause other health problems. Environmental exposures associated with myositis include ultraviolet radiation, stressful life events and muscle overexertion, collagen implants, infections such as retroviruses and streptococci bacteria, and certain drugs and chemicals. Some individuals with myositis also produce proteins in the blood called autoantibodies that react with certain parts of the person s own cells, called synthetases, which are involved in making new proteins. A syndrome called the anti-synthetase syndrome, which includes myositis and lung disease, is associated with having the anti-synthetase autoantibodies. Researchers are interested in studying differences in environmental exposures in individuals with myositis. This study is being conducted to determine if persons with the anti-synthetase syndrome have had different environmental exposures before disease onset compared with other patients with myositis who do not have this syndrome and also compared with healthy volunteers. Objectives: \- To determine whether selected infectious and noninfectious environmental exposures are more common in individuals who have myositis with the anti-synthetase syndrome, compared with healthy volunteers. Eligibility: \- Individuals who have been diagnosed with myositis (with or without anti-synthetase autoantibodies), and healthy volunteers without autoimmune disorders. Design: * Participants will be screened with a full medical history and physical examination, and will provide blood, urine and house dust samples. * Participants will complete questionnaires about their medical history and the types of exposures they have had at work, at home, and elsewhere. Participants who have myositis will also be asked about certain infections, heavy exercise or physical exertion, sun exposure, tobacco and alcohol use, and stressful events prior to being diagnosed with the disease. Healthy volunteers will be asked about the same exposures before the date of diagnosis of disease of the myositis subject to which they have been matched. * Participants will receive a kit that contains instructions and a filter to be put onto their vacuum cleaner to collect house dust in the bedroom. This dust will be kept for possible future analyses of infectious or toxic agents based on the other results from the study. * Individuals with myositis will have other tests as clinically indicated, including lung function tests and imaging studies.