The role of autoantibodies in the pathogenesis and diagnosis of autoimmune diseases

1. Big picture

Autoantibodies are antibodies directed against the body’s own antigens. In systemic autoimmune diseases they have two major roles:

1. Pathogenic role: they directly cause tissue injury, thrombosis, receptor stimulation/blockade, complement activation, or immune-complex disease.
2. Diagnostic role: they help identify the autoimmune disease, predict organ involvement, monitor activity, and guide prognosis.

Core exam idea: Autoantibodies are clinically useful, but a positive autoantibody alone is not a diagnosis. Always interpret them together with symptoms, organ involvement, inflammatory markers, complement levels, urine findings, imaging, and sometimes biopsy.

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