Antinuclear Antibodies (ANA) ANA or Anti-NucIear Antibody refers to antibodies against antigens in the nucleus → like dsDNA, centromeres, ribonucleoprotein. The immunofluorescence assay (IFA) is the main technique used to detect ANAs. Using fluorescence microscopy and serial dilution, a pattern and titer is reported. Positive ANA ≠ Autoimmune Disease! • +ANA can be seen in up to 33% of healthy adults, and should be interpreted in the context of other symptoms and physical exam findings • Titer: The higher the ANA titer, the more likely it will be clinically significant • Pattern: The ANA patterns are associated with different rheumatic diseases, but often not specific ANA Patterns and Associated Rheumatic Diseases: • Homogeneous: Systemic lupus erythematosus (SLE), Mixed connective tissue disease (MCTD), Drug-induced Lupus, Juvenile Idiopathic Arthritis (JIA) • Speckled: Systemic lupus erythematosus (SLE), Sjogren's Syndrome (SS), Polymyositis/Dermatomyositis (PM/DM), Systemic sclerosis or scleroderma (SSc) • Nucleolar: Diffuse systemic sclerosis/scleroderma, Polymyositis • Centromere: Limited systemic sclerosis/scleroderma • Peripheral: Systemic lupus erythematosus (SLE), Systemic sclerosis/scleroderma What diseases are associated with a +ANA? • Rheumatic Diseases: Lupus (SLE), Systemic Sclerosis (scleroderma), Rheumatoid Arthritis, Sjögren Syndrome, Myositis, Mixed Connective Tissue Disease (MCTD), Juvenile Idiopathic Arthritis, Drug-Induced Lupus • Non-Rheumatic Diseases: Malignancy, Lymphoproliferative Disorders, Infection, Autoimmune Thyroid, Autoimmune Hepatitis, Primary Biliary Cirrhosis, Drug-Induced, Inflammatory Bowel Disease, Interstitial Pulmonary Fibrosis, Multiple Sclerosis by Dr. Mithu Maheswaranathan @MithuRheum and Dr. Ann Marie Kumfer @AnnKumfer #Antinuclear #Antibodies #ANA #patterns #rheumatology #diagnosis #differential
