Immunological Investigation of Multisystem Autoimmune Disease Flashcards
Why are autoimmune diseases more common in women?
Oestrogen effects peripheral tolerance
What conditions are antinuclear antibody (ANA) associated with?
SLE (>95%) Drug-induced LE (95%) MCTD (95%) RA (50%) Sjogren's (60%) Scleroderma (60%) Dermatomyositis (15%)
Old age (>40%) Chronic inflammation (>30%) Neoplasia (around 10%) Chronic active hepatitis (70%) PBC (25%) Normaility (3-5%)
How useful is ANA in SLE and why?
sensitivity etc
High sensitivity (95%) Very Low specificity
- High negative predictive value
- Low positive predictive value
Good for ruling out ANA
4 different patterns of ANA staining are seen using flourescent test.
What are they?
Homogeneous:
Speckled Pattern Staining:
Nucleolar staining:
Peripheral/Membranous staining:
What is ANA Homogeneous pattern staining?
-Present where there are autoantibodies directed against chromosomal autoantigens
(double/single-stranded DNA or histone proteins)
What is ANA speckled pattern staining?
-Where there are autoantibodies directed against non-chromosomal nuclear proteins (which are physically distinct from the nucleic acids in the nucleus)
What is ANA nucleolar staining?
-Where autoantibodies are directed solely against nucleolar RNA
What is ANA Peripheral/Membranous staining?
-Where staining is confined to the nuclear membrane
How is the human nucleus effected by autoimmune disease?
The human nucleus contains numerous potential autoantigens (double-stranded DNA, single-stranded DNA, histone proteins, the nucleolus, and non-histone nuclear proteins). Autoantibodies are produced against different nuclear autoantigens in different connective tissue diseases. In some conditions, SLE particularly, autoantibodies can be produced against a range of nuclear autoantigens. This results in different staining patterns on testing when visualised down a microscope, the different patterns resulting from autoantibodies binding to autoantigens which vary in their physical distribution in the nucleus.
Homogeneous staining results from autoantibodies being directed against 1 or more of 3 nuclear autoantigens.
Name these autoantigens
Where do you see them?
Double stranded DNA
(dsDNA)
-SLE (60-90%)
-Some autoimmune liver disease
Single stranded DNA
(ssDNA)
-Non-specific
-Many inflammatory disorders
Histone proteins
- drug induced lupus
- other connective disorders
List the autoantigens which produce a speckled pattern of staining when relevant autoantidobies are present
Ro La Sm RNP Scl-70 Jo-1 Centromere
Ro is present in which diseases?
Sjogren's (60-70%) SLE (30-40%) SCLE RA Scleroderma Neonatal lupus
Nucleolar pattern ANA’s are usually directed against what?
What diseases are these common in?
Nucleolus specific RNA
- Scleroderma, systemic sclerosis and overlap syndromes (60-70%)
- Clinical varients (limited cutaneous, diffuse cutaneous)
- A range of variant-specific antibodies (e.g. fibrillarin, PM-Scl)
Peripheral/Membranous ANA
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Peripheral/Membranous ANA staining is seen where autoantibodies are being produced against what?
What diseases is this seen in?
dsDNA
SLE
Some autoimmune liver diseases