Immunodeficiency Flashcards
What is primary immunodeficiency?
Immunodeficiency caused by a genetic defect
What is secondary immunodeficiency?
Caused by:
- infection with agents that deplete immune cells
- malnutrition
- immunosuppressive drugs
What type of deficiences cause primary immunodeficiency?
- Antibody deficiencies
- Combined deficienies
- Disorders of immune regulation
- Phagocytic cell disorders
- Complement deficiencies
what causes congential agammaglobulimemia?
- Defects in expression of pre B-cell receptor or signalling
- Causes lack of circulating B lymphocytes
What are the diagnostic criteria for congential agammaglobulinemia?
- No IgA, M, D or E
- No tonsils
- Tiny lymph nodes
who is typically affected by congential agammaglobulinemia?
Men
How is congential agammaglobulinemia treated?
With regular transfusions of pooled human IgG
What causes common immunodeficiency?
Defects in B cell terminal maturation, causes reduced plasma cell numbers
What is the most common primary immunodeficiency?
Selective IgA deficiency
What causes hyper-IgM syndrome?
Defect in B cell class switch recombination
What happens in hyper-IgM syndrome?
- IgM levels in serum elevated
- Other antibody isotopes only present in trace amounts
What causes severe combined immuodeficiency?
- Defects in T cell development
- So neither T-cell dependent antibody responses nor cell mediated immunity
What causes DiGeorge anomaly?
Defective thymus development
What happens in IPEX?
- Mutations in Foxp3 gene encoding transcription factor vital for regulatory T cells
- Self-reactive T cells are free to cause autoimmune disease
What happens ALPS?
- Mutations in Fas prevent normal triggering of apoptosis in lymphcytes
- Uncontrolled lymphocyte proliferation
What happens in FHL?
- Mutations in one of several genes causes defective release of lytic granules
- lymphocytes expand in response to infection but can’t mount cytotoxic response but release IFN-gamma
What are immunodeficiency syndromes?
Heterogeneous group of disorders, both immune and extra immune manifestations
What causes chronic granulomatous disease?
Defective NADPH oxidase enzyme
What happens in CGD?
- Superoxide cannot be produced
- Microbes persist in phagosomes
- Granulomas form to control infection
How do glucocorticoids act as immune suppressants?
- Reduce secretion of inflammatory cyotkines
- Prevent mast cell degranulation
- Reduces T cell activation
