Snapshot A 40-year-old woman with a past medical history of thyroid disease reports having chronically dry eyes and dry mouth for the past year. She has used artificial tears with some improvement. She also reports having pain with sexual intercourse and has been forced to use lubrication. Physical exam reveals dry mucous membranes and bilateral swollen parotid glands. Upon laboratory evaluation, she is positive for antinuclear antibodies, anti-Ro, and anti-La antibodies. (Sjögren syndrome) Introduction Autoimmune Antibodies Disease Antibodies Systemic lupus erythematosus Antinuclear antibody high sensitivity Anti-double stranded DNA (dsDNA) high specificity helps monitor disease activity Anti-Smith highest specificity Anti-cardiolipin Lupus anticoagulant Antiphospholipid syndrome Anti-β2 glycoprotein Anti-cardiolipin Lupus anticoagulant Drug-induced lupus Anti-histonehigh specificity Sjögren syndrome Antinuclear antibody Rheumatoid factor Anti-ribonucleoprotein antibodies SS-A (anti-Ro) SS-B (anti-La) Mixed connective tissue disease Anti-U1-RNP (ribonucleoprotein) high specificity Scleroderma Anti-Scl-70 (anti-DNA topoisomerase I) high specificity Anti-centromere specific for limited scleroderma (CREST) Anti-RNA polymerase III Antinuclear antibody nucleolar pattern is specific for systemic sclerosis Dermatomyositis / Polymyositis Anti-synthetase (anti-Jo-1) Anti-helicase (anti-Mi-2) more specific for dermatomyositis Anti-signal recognition particle (SRP) more specific for polymyositis Other antinuclear antibody (ANA) positive diseases rheumatoid arthritis juvenile arthritis