Why are acquired connective tissue diseases considered autoimmune diseases?

Acquired connective tissue diseases are classified as autoimmune diseases because they result from the immune system reacting against the body's own components as if they were foreign substances.1

Evidence supporting this classification includes:

• Presence of Autoantibodies: Patients typically exhibit abnormally high levels of immunoglobulins (antibodies) in their blood, specifically directed against their own serum proteins and tissues.1
• Immune Complex Formation: Antigen-antibody complexes are frequently found at sites of tissue damage, where they can trigger inflammatory responses and tissue injury.1
• Cellular Aggregation: Sites of damage often contain accumulations of lymphocytes and plasma cells, which are the cells responsible for producing these antibodies.1
• Treatment Response: These conditions often respond favorably to corticosteroids and other medications that inhibit antibody production or suppress the immune system.12
• Associated Disorders: They are frequently linked to other conditions known or suspected to arise from an aberrant immune response.1