Antibodies and Associated Conditions

Polymyositis

ANA

Anti Jo-1 (myositis-specific antibody)

**Anti-signal recognition protein (most specific for polymyositis)

Dermatomyositis

ANA

Anti Jo-1 (myositis-specific antibody)

**Anti-Mi-2 antibody (most specific for dermatomyositis)

Systemic lupus erythematosus (SLE)

Screening: ANA (anti-nuclear antibodies)

Antiphospholipid antibodies (increased risk of arterial & venous thrombosis)

Specific: anti-double-stranded DNA & **anti-Smith (most specific)

Drug-induced lupus

ANA

Hallmark: anti-histone antibodies

Antiphospholipid syndrome

Antiphospholipid antibodies

Anticardiolipin antibodies (false negative for Syphilis: positive RPR/VDRL & negative FTA-ABS)

Sjogren syndrome

ANA

Best initial tests: antiSS-A (Ro) & antiSS-B (La)

Scleroderma (Systemic sclerosis)

ANA

Limited: anti-centromere antibodies

Diffuse: anti-SCL-70 (anti-topoisomerase) antibodies

Rheumatoid arthritis

Screening: RF

Specific: anti-CCP (cyclic citrullinated peptide)

Granulomatosis with polyangiitis (Wegener's granulomatosis)

C-ANCA (antineutrophil cytoplasmic antibodies)

Microscopic polyangiitis

P-ANCA (antineutrophil cytoplasmic antibodies)

Myasthenia gravis

Acetylcholine receptor antibodies

Anti-MuSK (muscle-specific kinase) antibodies: may be positive in in AChR-negative patients with myasthenia gravis

Hashimoto thyroiditis

Antithyroglobulin antibodies

Antithyroid peroxidase antibodies

Graves disease

TSH (thyrotropin) receptor antibodies

Ulcerative colitis

P-ANCA (antineutrophil cytoplasmic antibodies)

Crohn's disease

Antibodies vs. saccharomyces cerevisiae (ASCA)

Primary biliary cirrhosis/cholangitis (PBC)

anti-mitochondrial antibodies (AMA)

Primary sclerosing cholangitis (PSC)

P-ANCA (antineutrophil cytoplasmic antibodies)

Celiac disease

Preferred initial test: Transglutaminase IgA antibodies

Endomysial IgA antibodies