Characteristics and Disease Progression of Mixed Connective Tissue Disease and Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease in which the immune system
produces antibodies against the body's healthy cells and tissues. These antibodies, called
autoantibodies, contribute to the inflammation of various parts of the body and can cause
damage to organs and tissues. Mixed connective tissue disease (MCTD) is another autoimmune
disease that overlaps in terms of signs and symptoms with three other connective tissue
diseases, including SLE. In both SLE and MCTD, the immune system appears to be abnormally
activated by small nuclear ribonucleoprotein (snRNP) autoantigens. Furthermore, lung tissue,
in particular, appears to be affected by the immune response induced by snRNP autoantigens.
The causes of SLE and MCTD remain unknown. However, it is likely that a combination of
genetic, environmental, and possibly hormonal factors work together to cause the diseases.
Past studies suggest that several different genes may be involved in determining a person's
likelihood of developing SLE or MCTD, which tissues and organs are affected, and the severity
of the disease. The purpose of this study is to characterize immune system abnormalities,
genetic components, and disease progression in people with SLE and MCTD.

Participants will attend up to four study visits, at intervals of at least 3 months, over the
course of this study. Each study visit will include questionnaires, a physical exam, and
possibly blood and/or urine collection. At the end of the study period, participants may
choose to continue or discontinue participation.

Inclusion Criteria:

- Patients with known rheumatic diseases including systemic lupus erythematosus,
rheumatoid arthritis, connective tissue disease, undifferentiated connective tissue
disease

Exclusion Criteria:

- Poor venous access, unstable medical problems or significant cardiopulmonary disease,
anemia, leukopenia, thrombocytopenia, anticoagulation therapy, recent significant
changes in medication or pregnacy. Patient cannot be taking large dose of
corticosteroids (above 30mg per day) or cytotoxic drugs (cyclophosphamide,
azathiprine, cyclosporine, methotrexate).