autoantibodies in rheumatologic disease

Pathology: - antinuclear antibody - systemic lupus erythematosus - 95% sensitivity, poor specificty - also systemic sclerosis, Sjogren syndrome, MCTD - anti-double-strand DNA antibody - systemic lupus erythematosus - 60% sensitivity - at levels > 800 IU/mL virtually diagnostic of SLE - correlates with disease activity, especially renal disease - anti-Smith antibody - systemic lupus erythematosus - 30% sensitivity, 99% specificity - most specific lab test for SLE; does not correlate with disease activity - anti-U1 RNP antibody - mixed connective tissue disease (MCTD) - systemic lupus erythematosus - 100% sensitivity - high titers (> 1:10,000) seen with MCTD do not correlate with disease activity - anti-Ro/SSA antibody - Sjogren's syndrome 70% sensitivity - systemic lupus erythematosus - subacute cutaneous lupus erythematosus - risk for neonatal lupus erythematosis (rash & conduction block) - scleroderma - rheumatoid arthritis - anti-La/SSB antibody - Sjogren's syndrome 70% sensitivity - risk for neonatal lupus erythematosis (rash & conduction block) - scleroderma - rheumatoid arthritis - ribosomal P antibody in serum - 15% sensitivity for SLE - associated with CNS lupus & lupus hepatitis - anti-Scl-70 antibody - diffuse scleroderma 10-30% sensitivity - associated with pulmonary fibrosis - anti-centromere antibody - CREST syndrome 10-30% sensitivity, cutaneous lupus - associated with pulmonary hypertension - anti-proteinase-3 antibody (cANCA) - Wegener's granulomatosus 90% sensitivity for active disease - anti-myeloperoxidase antibody (pANCA) - microscopic polyangiitis 80% sensitivty - Churg-Strass syndrome 60% sensitivity - atypical pANCA seen with inflammatory bowel disease - anti-Jo-1 antibody - polymyositis 20-30% sensitivity - antisynthetase syndrome - associated with interstitial lung disease - anti-SRP antibody - polymyositis (found in 5% of patients with myositis) - immune-mediated necrotizing myopathy with muscle fiber necrosis - minimal inflammation - anti-Mi-2 antibody - dermatomyositis (rare) - anti-TIF1-gamma - dermatomyositis (70% sensitivity, 90% specificity) - also juvenile dermatomyositis - increased risk for malignancy - anti-MDA-5 antibody - dermatomyositis (rare) - interstitial lung disease, cutaneous ulcers, Gottron papules - poor prognosis - rheumatoid factor - rheumatoid arthritis 70% sensitivity, not specific - Sjogren's syndrome - cryoglobulinemia, others - anti-cyclic citrullinated peptide - rheumatoid arthritis 70% sensitivity, 95% specificity - more specific than rheumatoid factor - anti-histone antibody - drug-induced lupus 95% sensitivity - cryoglobulins - vasculitis (type 2 cryoglobulinemia) - hepatitis C - multiple myeloma - systemic lupus erythematosus - rheumatoid arthritis - cytoplasmic 5' nucleotidase 1A Ab - inclusion body myositis

Specific

autoantibodies in systemic lupus erythmatosus (SLE)

General

rheumatology

References

Medical Knowledge Self Assessment Program (MKSAP) 16. 18, 19. American College of Physicians, Philadelphia 2012, 2018, 2022 - Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022

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