Immunology: Autoimmune and Autoinflammatory diseases 1 + 2 Flashcards
Definition of autoinflammatory disease
Immunopathology in the absence of a pathogen, caused by the innate immune system.
Definition of autoimmune disease
Immunopathology in the absence of a pathogen, caused by the adaptive immune response
Definition of monogenic and polygenic immune diseases
single gene mutation vs multiple gene mutations causing the disease
What is the difference between an autoinflammatory disease Vs an autoimmune disease?
Autoinflammatory disease is immunopathology in the absence of a pathogen caused by the innate immune response, whereas autoimmune diseases are caused by the adaptive immune response.
A 19 year old Italian man presents to his GP with fevers lasting for 2-4 days, with abdominal pain, chest pain, arthritis and a rash. His white cells, CRP, ESR and amyloid A are raised. What is the most likely diagnosis?
Familial Mediterranean fever
monogenic auto-inflammatory disease
A 19 year old Italian man presents to his GP with fevers lasting for 2-4 days, with abdominal pain, chest pain, arthritis and a rash. His white cells, CRP, ESR and amyloid A are raised. How should this patient be treated?
- Colchicine: Binds to tubulin in neutrophils and disrupts neutrophil functions, including migration and chemokine secretion.
- Anakinra: Interleukin 1 receptor antagonist
- Etanercept: TNF alpha inhibitor
A 19 year old Italian man presents to his GP with fevers lasting for 2-4 days, with abdominal pain, chest pain, arthritis and a rash. His white cells, CRP, ESR and amyloid A are raised. What complications may arise in this patient?
Amyloidosis, leading to nephrotic syndrome and renal failure (Familial Mediterranean fever)
What is Colchicine?
An anti-gout medication that binds to tubulin in neutrophils and disrupts neutrophil functions, including migration and chemokine secretion. It is also used to treat familial Mediterranean fever.
An example of a monogenic auto-inflammatory disease
Familial Mediterranean Fever
-TRAPS
Outline the pathophysiology of autoinflammatory diseases
-Local factors at sites predisposed to disease lead to activation of innate immune cells such as macrophages and neutrophils, with resulting tissue damage
What monogenic mutations cause auto-inflammatory disease?
- NLRP3: Gain of function mutation. Increased NALP3/Cryopyrin causes increased activity of the inflammasome complex
- MEFV mutation: Decreased pyrin-Marenostrin causes increased activity of the inflammasome complex (ie neutrophil activation). Pyrin-Marenostrin is a protein expressed mainly in neutrophils
What is the inflammasome complex?
Causes increased interleukin 1, NFKappaB and apoptosis
Outline the pathophysiology of autoimmune disease
- Aberrant T cell and B cell responses in primary and secondary lymphoid organs lead to breaking of tolerance (Of self) with development of immune reactivity towards self-antigens (autoreactive T cells) and formation of organ-specific auto-antibodies.
- HLA associations are common in polygenic subtype
- Auto-antibodies are present.
What is ALPS-1/APECED?
- Auto-immune polyendocrine syndrome type 1
- Auto-immune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome
What is the pathophysiology of ALPS-1/APECED?
- Defect in AIRE (Auto-immune regulator)
- Defect in AIRE leads to failure of central tolerance (Autoreactive T cells and B cells)
- AIRE is a transcription factor involved in development of T cell tolerance in the thymus. It upregulates expression of self-antigens by thymic cells. Promotes T cell apoptosis.
A 6 year old boy presents to his GP with fatigue dizziness, fever, muscle aches and spasms in the muscles around the mouth. His blood pressure is 64/40 Lab investigations reveal a potassium of 6mmol/l, a serum calcium of 1.5mmol/l and a low PTH. What is the most likely diagnosis?
-Addisons and Hypoparathyroidism secondary to APS1/APECED (Auto-immune polyendocrine syndrome)
-An 11 year old boy presents to A&E with fatigue, dizziness and fever. Further investigation reveals blood pressure of 50/45 and hyperkalaemia. A blood test shows presence of antibodies for IL17 and IL22. What is the most likely diagnosis?
-Addison’s secondary to APECED
An example of monogenic auto-immune disease
- APS-1/APECED (Auto-immune polyendocrine syndrome type 1/ Auto-immune polyendocrinopathy Candidiasis ectodermal dystrophy syndrome)
- ALPS (Auto-immune lymphoproliferative syndrome)