Learning Objective
Identify key autoantibodies and associate them with their respective autoimmune diseases for diagnostic interpretation on examinations and clinical practice.
Important Autoantibodies and Associated Disorders
| Autoantibody | Associated Disease/Condition |
|---|---|
| Anti-postsynaptic ACh receptor | Myasthenia gravis |
| Anti-presynaptic voltage-gated Ca²⁺ channel | Lambert-Eaton myasthenic syndrome |
| Anti-β₂ glycoprotein I | Antiphospholipid syndrome |
| Antinuclear antibody (ANA) | Screening marker; commonly seen in SLE |
| Anticardiolipin, lupus anticoagulant | SLE, antiphospholipid syndrome |
| Anti-dsDNA, anti-Smith | Highly specific for SLE |
| Antihistone | Drug-induced lupus |
| Anti-U1-RNP (ribonucleoprotein) | Mixed connective tissue disease |
| Rheumatoid factor (IgM against IgG Fc) | Rheumatoid arthritis |
| Anti-cyclic citrullinated peptide (anti-CCP) | More specific to rheumatoid arthritis |
| Anti-Ro/SSA, Anti-La/SSB | Sjögren syndrome |
| Anti-Scl-70 (anti-DNA topoisomerase I) | Diffuse scleroderma |
| Anticentromere | Limited scleroderma (CREST syndrome) |
| Anti-synthetase (e.g., Anti-Jo-1), Anti-SRP, Anti-Mi-2 | Polymyositis/dermatomyositis |
| Antimitochondrial | Primary biliary cholangitis |
| Anti-smooth muscle, Anti-LKM-1 | Autoimmune hepatitis |
| MPO-ANCA (p-ANCA) | Microscopic polyangiitis, EGPA, UC, PSC |
| PR3-ANCA (c-ANCA) | Granulomatosis with polyangiitis |
| Anti-phospholipase A2 receptor | Primary membranous nephropathy |
| Anti-hemidesmosome | Bullous pemphigoid |
| Anti-desmoglein | Pemphigus vulgaris |
| Antithyroglobulin, Anti-TPO | Hashimoto thyroiditis |
| Anti-TSH receptor | Graves disease |
| IgA anti-endomysial, IgA anti-tissue transglutaminase | Celiac disease |
| Anti-glutamic acid decarboxylase | Type 1 diabetes mellitus |
| Antiparietal cell, Anti-intrinsic factor | Pernicious anemia |
| Anti-GBM (anti-glomerular basement membrane) | Goodpasture syndrome |
Activity
Key Exam Tips
- Anti-dsDNA and anti-Smith = specific for SLE
- Anti-CCP = most specific for RA
- c-ANCA (PR3) → Wegener (GPA)
- p-ANCA → microscopic polyangiitis/EGPA
- Anti-TPO + antithyroglobulin → Hashimoto
- Anti-endomysial or anti-TTG → celiac disease
