Immune Pathophysiology Flashcards
1) What is the most common cause of immunodeficiencies?
2) When are they often diagnosed (in life)?
1) Most are inherited diseases. They are often X-linked and are mutations which affect cytokines
2) Early in life, due to recurrent infections
What are the different mechanism that lead to B-cell deficiencies?
Dysfunction in B-cell maturation and proliferation.
Some lead to depletion of all Igs and other only lead to depletion of certain isotypes.
The deficiency can lead to increased risk of EC bacteria
Mention some types of immunodeficiencies (besides B-cell deficiency)?
T-cell: Severe. The problem is often related to the TCR or cytokine production
Complement: Dysfunctional complement proteins
Phagocytosis: Problems related to phagocytosis of microorganisms.
Can a patient present with more that one type of immunodeficiency?
Yes, there is a combined T- and B-cell deficiency which is really severe and fatal within a couple of years
What is a type 1 hypersensitivity reaction and what are some common allergens?
An IgE-mediated abnormal immune response. Some common allergens are pollen, food or medicine
Which cells are associated with a type 1 hypersensitivity reaction?
T2H: Is activated by the allergen
B-cells: Class-switch to IgE production
Mast cells: Are induced to release Histamine (granules) when bound to IgE
Eosinophils and basophils are also involved later in the process
What characterizes the primary and secondary phase of a type 1 reaction?
Primary: Vasodilation -> increased vascular permeability -> edema (due to histamine)
Secondary: Eosinophils infiltration and inflammation
What is anaphylaxis?
Systemic release of histamine which lead to massive vasodilation, hypotension and airway edema.
Mention 3 kinds (diseases) of type 1 reactions
Allergic rhinitis, food allergies and urticarial rash
What types of immune reactions can be responsible for initiation a type 2 hypersensitivity reaction?
Anitbody cellular dysfunction: Binding of antibody to cell makes it dysfunctional
Anitbody mediated cell cytotoxicity: Lysis of cells
Complement-antibody complex formation: Complex are deposited in EC tissue
Compelment
What is a type 3 hypersensitivity reaction?
When antigen-antibody complexes are formed and blood vessel and then subsequently are deposited in the epithelium where it induces inflammation. The inflammation leads to tissue damage.
What is a type 4 hypersensitivity reaction?
T-cell mediated response which is delayed compared to the others. Examples are allergic contact dermatitis.
What is an autoimmune disease?
When the immune system reacts against self-antigens. The reaction can be either systemic or local.
The etiology of autoimmune diseases are unknown. But some suggest what?
That it is a combination of environmental and genetics factors. The diseases are thought to be triggered by a exogenous agent.
What is covered by the three mechanism mentioned below in relation to autoimmune diseases:
1) Breakdown of T-cell anergy
2) Sequestered antibodies
3) Molecular mimicry
1) Some autoimmune diseases a related to dysfunction of T-cell anergy
2) Some antigens are hidden and when they are reintroduced it triggers a reaction
3) Some substances trigger autoimmunity since their epitodes are very similar to self-antigens
