A 35-year-old woman with CREST syndrome (limited systemic sclerosis) is most likely to test positive for which specific autoantibody, and what is its clinical correlation?
- A Anti-topoisomerase I (Scl-70) — associated with diffuse cutaneous SSc and pulmonary fibrosis
- B Anti-centromere antibody (ACA) — associated with limited SSc/CREST and pulmonary arterial hypertension (not diffuse fibrosis) ✓
- C Anti-RNA polymerase III antibody — associated with diffuse SSc and scleroderma renal crisis
- D Anti-U1 RNP — associated with mixed connective tissue disease
Explanation
Anti-centromere antibodies (ACA) target CENP-A, CENP-B, and CENP-C proteins of the kinetochore and are found in 70–80% of patients with CREST syndrome (Calcinosis, Raynaud's, Esophageal dysmotility, Sclerodactyly, Telangiectasia = limited cutaneous SSc). These patients have a lower risk of severe internal organ fibrosis but are at significantly increased risk of pulmonary arterial hypertension (PAH). Anti-Scl-70 targets DNA topoisomerase I and correlates with diffuse cutaneous involvement and interstitial lung disease. Anti-RNA Pol III associates with diffuse SSc and renal crisis.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
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