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Anti-RNP Antibody
Related Subjects: |Ferritin |CEA |ESR |CRP |ALP |LDH |HbA1c |Alpha Fetoprotein |Anti-Hu ab |Biochemical Lab values
🧪 Antibodies to ribonucleoprotein (RNP) are often found in systemic rheumatic diseases. High titres, especially Anti-U1RNP, are a hallmark of Mixed Connective Tissue Disease (MCTD) and help differentiate it from other autoimmune conditions.
🔎 About
- Types of RNP Antibodies:
- 🧬 RNP (Ribonucleoprotein): Autoantibodies directed against nuclear proteins bound to RNA molecules.
- 🎯 U1RNP: Targets U1 small nuclear ribonucleoprotein (snRNP) involved in RNA splicing - most clinically relevant subtype.
- Association with Anti-Sm: May co-exist with Anti-Smith antibodies, particularly in SLE, giving a more complex autoimmune profile.
📈 Elevated In
- Mixed Connective Tissue Disease (MCTD):
- ✅ Seen in 95–100% of cases; virtually diagnostic when titres are high.
- 🌈 Clinical overlap with lupus, scleroderma, and polymyositis.
- Features: Raynaud’s phenomenon ❄️, arthritis 🤲, myositis 💪.
- Systemic Lupus Erythematosus (SLE):
- 🩺 Often present but less specific than in MCTD.
- Associated with milder disease (arthralgia, rashes) unless co-existing with Anti-Sm.
- Progressive Systemic Sclerosis (PSS):
- Occasional positivity, usually in overlap syndromes.
- ⚠️ Linked with pulmonary hypertension and interstitial lung disease.
📌 Clinical Significance
- 🔬 Diagnosis: High titres virtually define MCTD.
- 📉 Prognosis: Suggests chronic but manageable course, especially in MCTD.
- 📊 Monitoring: Serial titres sometimes used to follow activity in MCTD/SLE.
🧪 Testing
- 💡 Indirect Immunofluorescence (ANA screen): Characteristic speckled pattern suggests RNP positivity.
- 🧾 ELISA: Confirms and quantifies antibody levels; more specific for U1RNP.
📚 References
- UpToDate: Mixed connective tissue disease overview.
- Oxford Handbook of Rheumatology.
- ARUP Laboratory Test Directory – Anti-U1RNP.
| The content on this website is provided for educational and informational purposes only to support exam preparation (e.g., MLA, MRCP, USMLE) and learning. This is NOT medical advice, diagnosis, treatment, or professional guidance. It does not replace consultation with a qualified healthcare professional, official guidelines (e.g., NICE, GMC, BNF), or supervised clinical practice. Always verify information with current, authoritative sources. Makindo and its contributors accept no liability for any reliance on this content, including errors, omissions, or any resulting harm, loss, or consequences. By using this site, you agree to these terms. |
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