Autoimmune and Autoinflammatory diseases Flashcards
What is an auto-inflammatory diseae?
Activation of innate immune cells such as macrophages and neutrophils, with resulting tissue damage
What is an auto-immune disease?
(Activation of adaptive immune-response against self)
Activation of aberrant T cell and B cell responses in primary and secondary lymphoid organs lead to breaking of tolerance with development of immune reactivity towards self-antigens
Name two examples of (rare) monogenic auto-inflammatory diseaes
- Familial Mediterranean Fever
- TRAPS
Name examples of a Mixed pattern autoimmune/auto-inflammatory disease
- Axial spondyloarthritis
- Psoriatic arthritis
- Behcet’s syndrome
Name 3 examples of polygenic auto-inflammatory diseases
- Crohn’s disease
- UC
- Osteoarthritis
- Giant Cell arthritis
- Takayasu’s arteritis
Name 3 Examples of polygenic auto-immune diseases
- Rheumatoid arthritis
- Myaesthenia Gravis
- Pernicious anaemia
- Graves
- SLE
- PBC (Primary Biliary Cirrhosis)
- ANCA associated vasculitis
- Goodpasture disease
Name examples of Monogenic auto-immune diseases (rare)
ALPS
IPEX
What signaling pathway’s are commonly abnormal in monogenic auto-inflammatory diseases?
Abnormal signalling via key cytokine pathways involving TNF-alpha and/or IL-1 is common
What are typical clinical features of monogenic auto-inflammatory diseases?
periodic fevers
- inflammation – eg skin/joint/serosal/CNS
- high CRP
What kind of disease is Familial Mediterranean Fever?
What is the epidemiology + inheritence pattern ?
It is a monogenic auto-inflammatory disease
Autosomal recessive
Epidemiology in those of mediterranean descent (particularly armenian + jewish, turkish), varying prevalence with 1/4 carriers (armenian 1 in 500 have diseaes)
What is the pathophysiology of familial mediterranean fever?
Generally decreased regulation of neutrophils + increased neutrophil activation
Mutation in MEFV gene
MEFV gene encodes pyrin-marenostrin
Pyrin-marenostrin expressed mainly in neutrophils
Failure to regulate cryopyrin driven activation of neutrophils
What is the clinical presentation of someone with familial mediterranean fever?
All patients experience fever attacks lasting 1–3 days that recur over weeks to months
Most patients (95%) experience abdominal pain (peritonitis) and arthralgia (75%).
Other manifestation
- rash
- arthritis
- chest pain (pleurisy and pericarditis)
What is the main complicaiton of Familial Mediterranean Fever?
Risk of AA amyloidosis (with deposition in kidneys –> renal failure)
What lab finidngs would you find in an individual with Familial Mediterranean fever?
- High CRP
- High SAA (Serum Amyloid A)
+ test for MEFV mutation
How would you treat Familial Mediterranean fever?
What is the effect?
- Colchicine 500ug bd - binds to tubulin in neutrophils and disrupts neutrophil functions
including migration and chemokine secretion
- Anakinra (Interleukin 1 receptor antagonist)
- Etanercept (TNF alpha inhibitor)
What is IPEX ?
What types of disease is it
what does it stand for (abbreviation)
what is the inheritence pattern
What is the epidemiology
Immune dystregulation, polyendocrinopathy, enteropathy, X-linkey syndrome is a monogenic auto-immune disease with muation in the FOXP3 gene leading to disregulation of T-cell function
X-linked recessive disease
Rare (1 in 1.6 million)
What is the clinical presenation of IPEX?
Mutation in transcription factor FOXP3 → unchecked activation of T cells against host tissues
Diarrhoea, diabetes and dermatitis
Presenation in early infancy
- Lymphadenopathy and/or chronic lymphoid tissue hypertrophy (e.g., enlarged tonsils)
- Eczema (+/- other derm)
- Autoimmune endocrine conditions (e.g., hyperthyroidism or hypothyroidism, type 1 diabetes mellitus in male individuals)
- Enteropathy, manifesting as e.g., chronic diarrhea
How does a mutaiton in the FOXP3 gene lead to diseae?
FOXP3 =IPEX
Usually FOXP3 is an transcription factor improtant for development of CD25+ TREG cells
Mutation leading to
- unchecked activation of T cells against host tissue (no negaive regulation of T-cells)
- Autoreactive B-cells
What is ALPS?
What types of disease is it
what does it stand for (abbreviation)
what is the inheritence pattern
What is the epidemiology
Auto-immune lymphoproliferative syndrome is a monogenic auto-immune disease with defect in the apoptosis pathway of self-reactive lymphocytes
Autosomal Dominant disease (incomplete penetrance)
Rare (a few houndret cases worldwide)
What muation causes ALPS?
What is the pathophysiology?
Mutations within FAS pathway (E.g. TNFRSF6 -encodes FAS) →Disease is heterogeneous depending on the mutation
Leading to
Defect in apoptosis of lymphocytes → proliferation of self-reactive, antigen specific lymphocyte lineages
Autoimmune lymphoproliferative syndrome: an autosomal dominant disorder
Presentation: generalized adenopathy, hepatosplenomegaly, and autoimmunity
What is the clinical presenation of ALPS?
High lymphocyte numbers with large spleen and lymph nodes →CD4-CD8- T cells
- Auto-immune disease→ commonly auto-immune cytopenias
- Lymphoma
What role do gene mutations in HLA genes play in Polygenic auto-inflammatory vs. polygenic auto-immune diseases play?
Usually play a bigger role in auto-inmmune diseases, less relevant for auto-inflammatory diseases
Why are certain polygenic auto-inflammatory diseases (e.g. Crohn’s) are site-specific?
Local factors at sites predisposed to disease lead to activation of innate immune cells such
as macrophages and neutrophils, with resulting tissue damage