1 / 20

Autoantibodies in PM and DM

Autoantibodies in PM and DM. Autoantibodies: >90% Positive ANA: 60-80% More in overlap Low in IBM Defined antibodies: 50% Myositis-specific antibodies: 35-40% Most common Ab (Jo-1): 20%. Myositis-Specific Antibodies. High disease specificity Appear prior to disease onset

etenia
Download Presentation

Autoantibodies in PM and DM

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Autoantibodies in PM and DM • Autoantibodies: >90% • Positive ANA: 60-80% • More in overlap • Low in IBM • Defined antibodies: 50% • Myositis-specific antibodies: 35-40% • Most common Ab (Jo-1): 20%

  2. Myositis-Specific Antibodies • High disease specificity • Appear prior to disease onset • Absence does not exclude • Assist in diagnosis and classification

  3. Established Myositis-Specific Autoantibodies • Anti-synthetases 25% • Anti-Jo-1 20% • Non-Jo-1 4 - 8% • Anti-Mi-2 5 - 10% • Anti-SRP 5% • “signal recognition particle” • (Anti-PM-Scl) 5 - 10%

  4. Anti-Synthetases: Indirect Immunofluorescence Anti-Jo-1 Anti-OJ Anti-PL-12

  5. Anti-Synthetase Syndrome Myositis 95% Interstitial Lung Disease 70-90% Arthritis 50-90% Raynaud’s Phenomenon 60% Fevers 85% Recurrences 60% Mechanic’s Hands 70%

  6. Anti-Mi-2: Indirect Immunofluorescence

  7. Anti-Mi-2: Clinical Picture • High specificity for myositis • low sensitivity • Relative specificity for dermatomyositis • Adults and children • Rash often prominent

  8. Anti-SRP: Indirect Immunofluorescence

  9. Signal Recognition Particle Autoantibodies • Acute onset • Severe weakness • No skin involvement • Biopsy may lack inflammation • Immune-mediated necrotizing myopathy

  10. DIAGNOSIS and the Myositis Autoantibodies • High specificity, Low sensitivity • Define patient subgroups • May help when extra-muscular features predominate

  11. Inclusion Body Myositis • Older age of onset • Slow Progression • Longer duration to diagnosis • Distal involvement: IBM>PM/DM • Forearm flexors • Quadriceps • Lesser degree of CreatineKinase elevation

  12. HISTOLOGIC FEATURES INCLUSION BODY MYOSITIS • Light Microscopy • Rimmed vacuoles with basophilic granules • Eosinophilic inclusions • Electron Microscopy • Inclusion bodies with microtubular filaments

  13. Histopathology of IBMDalakas: Rheum Dis Clin NA 28:779,2002 Endomysial Inflammation Sourrounding Non-necrotic fibers

  14. Inclusion Body Myositis: Rimmed Vacuoles

  15. IBM PathologyDalakas Rheum Dis Clin NA 28:779,2002 Rimmed vacuoles; Basophilic Granules EM: Tubulofilaments

  16. Extra-Muscular Manifestations • Systemic • Pulmonary • Interstitial Lung Disease • Respiratory Muscle Weakness • Aspiration • Infection • Toxicity • Cardiac • GI

  17. Malignancy and Myositis • 32% DM, 15% PM • Risk greatest in 1st year • Increased risk in those age >45 • May have paraneoplastic course • Ovarian cancer overrepresented • Colon, lung, pancreatic, breast, lymphoma • Risk is higher with anti-p155/140 • lower with other myositis antibodies

  18. Differential Diagnosis of Idiopathic Inflammatory Myopathy • Other myopathies (dystrophy, metabolic) • Neuropathies (ALS, Myasthenia gravis) • Drug-induced myopathies • Infectious myopathies • Endocrine myopathies (hypothyroidism, Cushing’s syndrome)

  19. DRUG-INDUCED MYOPATHY • D-Penicillamine • Zidovudine • Lipid Lowering Agents • Colchicine • L-Tryptophan • Drugs of Abuse • Endocrine • Chloroquine

  20. Suggested Reading • Primer on the rheumatic diseases • For greater depth: • Miller FW: Inflammatory Myopathies: Polymyositis, Dermatomyositis, and Related Conditions (Chapter 75). In: Koopman et al, Arthritis and Allied Conditions

More Related