Diagnosis of Autoimmune Disease Flashcards
Define: Sensitivity
How good the test is at identifying people with the disease
Define: Specificity
How good the test is at defining people without the disease.
What is the positive predictive value?
The proportion of people with a positive result that have the disease.
What is the negative predictive value?
The proportion of people with a negative result that don’t have the disorder.
What is a non-specific diagnostic test?
Inflammatory marker
What is a specific diagnostic test?
HLA typing, autoantibody testing.
What are ESR and CRP ? (not what they are abbreviations of)
Non- specific markers of systemic inflammation.
What does ESR stand for?
Erythrocyte sedimentation response.
What makes both ESR and CRP?
Liver
Why is ESR measured? (Inflam agents)
Inflammatory agents released by liver –> plasma thicker = Inflammatory level.
Why is CRP measured?
It is like complement, rapidly used up. Can use that to check inflammatory level.
What other markers rise with systemic inflammation?
Ferritin and Fibrinogen.
What are the other markers of systemic inflammation?
Haptoglobin, Albumin, Complement.
What do anti-nuclear antibodies do?
Engulf own leukocyte nuclei.
Examples of Extractable Nuclear Antigens include?
> Ro and La = Proteins involved in transcription of DNA.
dsDNA
Ribonuclear Protein = Involved in transcription and translation.
What can ANA detection diagnose?
Lupus
What type of cell is used in ANA detecting?
Fibrocyte type cells - prominent nuclei
What are the steps of ANA detection?
> Fibrocyte cells onto slide
Serum from pt, if auto-antibodies present –> bind to nuclei
To see binding, use flourescent marker - binds to Fc portion of IgG.
What is Rheumatoid Factor (RF) ?
An autoantibody directed against Fc portion of IgG.
What disease is RF commonly found?
Rheumatoid Arthritis
What other disease is RF found in?
Polyclonal stimulation of B cells (chronic infection).
What is ACPA (Anti-citrullination protein antibody) a useful prognostic marker for?
RA
What do pt’s with +ACPA have?
More severe and erosive disease
In ANCA (Anti-neutrophilic cytoplasmic testing) what is used as a ANA substrate?
Granulocytes.
What glows up with cytoplasmic ANCA?
Cytoplasm
What glows with peri-nuclear ANCA?
Nucleus
What is a disease flare?
+ve ANCA in a ANCA -ve pt.
What autoantibody is found in primary biliary sclerosis?
Anti-mitochondria antibody
What autoantibody is found in autoimmune hepatitis?
Anti smooth-muscle and anti-liver/kidney/microsomal antib’s.
Are Type 1 diabetes autoantibodies pathogenic or non?
Non - mostly.
In later Type 1 diabetes what happens to the autoantibodies?
Disappear as the disease progresses
In early Type 1 what happens to the autoantibodies?
Increases as the disease progresses
What is destroyed in Type 1 diabetes?
B islet cells
