The autoimmune diseases

Autoimmune diseases occur when the body produces antibodies against its own tissue. Systemic lupus erythematosus is characterized by the production of antibodies against the cell nucleus (antinuclear antibodies, or ANA) and the deposition of antibodies, complement and immune complexes in various tissues. Rheumatoid arthritis involves the production of ANAs, as well as rheumatoid factor. Deposition of antibodies in the joint can cause a localized inflammatory reaction. Juvenile rheumatoid arthritis occurs in children and adolescents and is similar to adult rheumatoid arthritis. Sjogren's syndrome is caused by the production of antibodies to tear ducts, salivary glands and other glands. Scleroderma (systemic sclerosis) also involves the production of antibodies against the cell nucleus and nucleolus. Polymyositis is characterized by an infiltration of muscle tissue by lymphocytes, which results in inflammation.