Immuno - autoimmune and autoinflamm disease Flashcards
Graves disease - pathophysiology?
anti-TSH receptor antibodies –> activation of TSH receptor that is not responsive to -ve feedback
What type of hypersensitivity disorder is Graves disease
Type II
- antibodies against self –> receptor activation
Which thyroiditis is associated with high T4? and which one with low T4?
High T4 = De Quervains (painful)
Low T4 = Hashimoto’s (anti-TPO)
Hashimoto’s thyroiditis - clinical Fx
Features of hypothyroidism (constipation, lethargy, cold intolerance)
GOITRE - irregular!
Why is there goitre in hashimoto’s thyroiditis?
Lymphocyte infiltration of the thyroid due to binding of autoantibodies
Which autoantibody is associated with Hashimoto’s
Anti-THRYOGLOBULIN
WHY is measuring anti-thyroid antibodies a bit shit
LOADS of women>65yo with antithyroid antibodies without any thyroid disease..only a small proportion actually have hypothyroidism
Low TSH. Normal T3/T4. What is the Dx and what is the significancd
Subclinical hyperthyroidism - may progress to primary hyperthyroidism, esp if they have anti-TPO +ve
Pathophysiology of T1DM? Therefore what type of hypersensitivity is it?
CD8+ T cells recognise auto antigens on beta cells
Type IV - t cell mediated
What auto antigens are recognised by T-cells in T1DM?
GAD65
IA2 (islet antigen 2)
Antibodies seen in T1DM
anti-islet cell
anti-GAD
anti-insulin
anti-IA2
Clinical Fx of B12 deficiency
- Degeneration of cord
- Optic neuropathy
- Peripheral neuropathy
Pernicious anemia - what is it?
- Autoantibodies to gastric parietal cells + intrinsic factor
B12 malabsorption –> deficiency –> neurological Fx
Case: drooping eyelids + weakness on repetitive activity + Sx worse at end of day
Dx?
Myasthenia gravis
Myasthenia gravis = pathophysiology
Anti-AChR antibodies
Therefore ACh can’t bind and muscle cell is not depolarised –> no contraction
Special test for Dx of Myaesthenia gravis
Tension test
Myasthenia gravis - what type of hypersensitivity disorder is it?
Type II - antibody against a self antigen
Good pasture’s syndrome - what is the offending antibody?
Antibody vs alpha3 subunit of Type IV collagen
Immunohistochemistry for anti-GBM: what is a +Ve result?
linear IgG deposition along GBM
Best antibody for detecting rheumatoid arthritis
Anti-CCP
Name 2 genetic predispositions to rheumatoid arthritis?
1) HLA DR4 + 1 subtypes
2) PAD2 and 4 PMs
How does HLA affect susceptibility of RA?
Certain alleles of HLA DR4 and HLA DR1 bind to ARTHRITOGENIC PEPTIDES + CITRULLINATED PEPTIDES w high affinity
What infection is associated with rheumatoid arthritis? why?
P gingivalis - gum infection
It expresses PAD enzyme?! thus promotes citrullination
How does PAD polymorphism –> RA development?
PAD2 and 4 = involved in citrullination of arginine
Certain polymorphisms are associated with increased activity –> high load of citrullinated proteins
What is rheumatoid factor
Antibody directed against Fc region of IgG.
This antibody is an IgM
B cell involvement in Rheumatoid arthritis - give 2 ways
1) Type 2 response = anti-CCP activity –> complement, NK and macrophage activation
2) Type 3 response = immune complexes formed (by Anti-CCP and RF) + deposited –> complement activation
How is the point affected (macroscopically) in RA
Increased synovial fluid volume
Inflamed synovial tissue -> panes formation which invades cartilage + adj tissue
4 diseases assoc with ANA +ve
SLE
Sjogren’s
Scleroderma
Dermatomyositis
ANA +ve - is this result specific to autoimmune disease?
NO it is often found in normal individuals
Which cells are used to test for ANAs?
Hep2 cells