Autoimmune Markers

OVERVIEW

• numerous autoimmune markers will overlap between conditions and varying specificity and sensitivity

MARKERS

Antinuclear Antibodies (ANA)

• low specificity -> SLE and other autoimmune diseases

Rheumatoid factor

• IgG vs IgM
• low specificity
  • -> RA
  • -> mixed cryoglobulinaemia
  • -> subacute bacterial endocarditis
  • -> any chronic antigenic stimulation

Anticardiolipin

• low specificity
  • -> antiphospholipid syndrome
  • -> SLE
  • -> other autoimmune diseases
  • -> viral illnesses

Anti-DNA and Anti-Smith

• -> SLE

Anti-Ro and La

• -> SLE with congenital heart block
• -> Sjögren syndrome

Anti-centromere

• -> limited cutaneous scleroderma (CREST)

Anti-ribonuclear protein

• -> SLE
• -> mixed connective tissue disorder
• -> undifferentiated connective tissue disorder

C3 and C4

• -> falls in: SLE, autoimmune chronic active hepatitis
• -> rise in: biliary obstruction, nephrotic syndrome, acute phase response

Antineutrophil Cytoplasmic Antibody (ANCA)

• -> c-ANCA: Granulomatosis with polyangiitis (GPA) > polyarteritis nodosa
• -> p-ANCA: polyarteritis nodosa > Granulomatosis with polyangiitis (GPA)
• -> drug therapy: penicillin, sulphonamides, quinolones, phenytoin, thiazides

Antiglomerular Basement Membrane

• -> Goodpasture syndrome

Anti-smooth muscle

• -> autoimmune disease
• -> chronic active hepatitis
• -> EBV

Anti-mitochondrial

• -> primary biliary cirrhosis
• -> chronic active hepatitis
• -> idiopathic cirrhosis

Anti-gliadin, Anti-endomseal, Anti-transglutaminase

• -> Coeliac disease

Anti-intrinsic factor and Parietal Cell Antibody

• -> Pernicious anaemia

Anti-TSH receptor

• -> autoimmune thyroid disease (Graves disease and Hashimoto thyroiditis)

Anti-acetylcholine receptor protein and Muscle-specific receptor tyrosine kinase (MuSK) antibody

• -> MG