Autoanticorpos

  • Imunoglobulinas circulantes que detetam antigénios self
  • Perfil contribui o fenótipo
  • Etiology/inciting event not completely understood
  • Autoimune é diferente de autoinflamatório
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Tabela completa com todos os anticorpos
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ANA
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  • Autoanticorpos que detetam componentes primariamente nucleares (DNA ou small nuclear ribonucleoproteins (snRNP)
  • Screening tool - good sensititvity (assay-dependent).
  • More harm than good - low disease specificity. Many false positives. Get a titer - Positive if >1:40 or 1:80 (better)
    • 1:40 prevalence 32%
    • 1:80 prevalence 13%
    • 1:160 prevalence 5%
    • 1:320 prevalence 3%
    • Conditions other than autoimmune CTD with positive ANA
      • Elderly person
      • Pregnant women
      • Relatives of patients with CTD
      • Other autoimmune disease (primary biliary cirrhosis, autoimmune thyroiditis)
      • Drugs (eg. procainamide, hydralazine)
      • Chronic infections
      • Neoplasms
      • Healthy persons
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  • Assays to identify ANA
    • Immunofluorescence
      • Directed against nuclear antigens on Hep-2 cells (human SCC tumor line)
      • High number of antigens, High sensitivity, high cost
      • Staining patterns
        • Homogenous - SLE
        • Peripheral - SLE
        • Speckled - MCTD, SLE, SSc, Sjogren
        • Nucleolar - SSc, SLE
        • Centromeric - CREST
    • ELISA
      • Solid phase immunoassay
      • Low number of antigens, low sensitivity, low cost
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dsDNA
  • Correlates well with nephritis
  • Tem título que traduz a atividade da doença
SSA (Ro)
  • Correlates well with photosensitivity, vasculitis
    • Com a exposição solar UVB os Ro são expostos na superfície da célula
  • Associado a Sjogren
  • 90% of La (+) are also Ro (+)
  • 50% of Ro (+) are also La (+)
Smith
  • Correlaciona com envolvimento renal e SNC
Ac Antihistonas
  • têm importância no lúpus sistêmico induzido por fármacos. Não tem importância no lúpus cutâneo! (Prof Margarida)
Anti RNP
  • Doença mista do tecido conjuntivo
Anticoagulante Lúpico ou Antifosfolípidos
  • Pedir APTT
Dermatomiosite
  • Anti-Mi-2
  • Anti-TIF1-gama
  • Anti-MDA5
  • Anti-NXP-2
  • Anti-SAE
Síndrome Anti-Sintetase
Esclerose Sistémica
  • Anti-topoisomerase-1 (Scl-70)
  • Anti-RNA polimerase III
  • Anti-centromero
ANCA