Type 1 hypersensitivity Flashcards
How do small molecule drugs contribute to allergic reactions?
Small molecule drugs can trigger allergic reactions by either crossing biological membranes or being directly injected into the circulation. They can react with endogenous proteins to form antigenic structures that the immune system recognizes.
What is required for IgE production in allergic reactions?
For IgE production, naïve T lymphocytes must be programmed to a Th2 phenotype, and B lymphocytes must undergo a class switch from IgM to IgE production.
Where are mast cells located in the body?
Mast cells are tissue-dwelling effector cells found in connective tissue and mucosal surfaces, with a perivascular distribution.
What is the primary function of mast cells?
Mast cells respond to parasites, allergens, and some bacteria. Upon activation, they release mediators that cause plasma extravasation, tissue oedema, bronchoconstriction, and leukocyte recruitment.
What types of diseases are associated with mast cells?
Mast cells are associated with diseases such as asthma, urticaria, angioedema, rhinitis, parasite infections, autoimmune diseases, and more.
How do mast cell mediators affect the body?
Mast cell mediators initiate both early and late inflammatory events, including the activation of sensory nerves, which release neurotransmitters like substance P, causing neurogenic inflammation.
What is the main role of basophils in allergic reactions?
Basophils, which develop in the bone marrow and circulate in the blood, migrate to sites of allergic inflammation and release mediators, playing a role in the allergic response.
How are mast cells and basophils similar and different?
Both mast cells and basophils contain abundant cytoplasmic granules that store pre-formed mediators. However, basophils are less understood and have distinct differences compared to mast cells, particularly in their migration patterns and functions.
What is anaphylaxis, and how is it triggered?
Anaphylaxis is a severe, life-threatening allergic reaction characterized by fast onset and can be triggered by allergens via any route of contact, such as food, drugs, or insect stings. Direct delivery methods like injection or stings tend to cause more severe reactions.
What distinguishes small molecule drugs from fully antigenic proteins in terms of allergic reactions?
Small molecule drugs become allergenic when they react with endogenous proteins to create an antigenic form, whereas fully antigenic proteins are inherently capable of provoking an immune response without needing such a chemical reaction.
How do small molecule drugs overcome biological barriers to trigger allergic reactions?
Small molecule drugs can cross biological membranes or be directly injected into the circulation, bypassing initial immune system barriers and activating allergic responses.
How do mast cells contribute to allergic inflammation?
Upon activation, mast cells release mediators that cause plasma extravasation, tissue oedema, bronchoconstriction, and recruit other leukocytes, leading to inflammatory responses in allergic reactions.
How do mast cells mediate neurogenic inflammation?
Mast cell activation causes the release of mediators that activate sensory nerves, leading to axon reflexes. These reflexes release peptidergic neurotransmitters like substance P, which contribute to neurogenic inflammation.
What role do basophils play in allergic reactions?
Basophils, though less understood than mast cells, migrate to sites of allergic inflammation and release mediators that contribute to the allergic response.
How do basophils differ from mast cells in terms of their function and understanding?
Basophils have similarities to mast cells but remain enigmatic and are less well understood. They share the role of releasing mediators during allergic reactions but differ in their migration and activation patterns.
What is the typical onset and severity of anaphylaxis, and how is it triggered?
Anaphylaxis has a fast onset and can be triggered by allergens via any route, including food, drugs, or insect stings. Direct routes like injections or stings tend to cause more severe reactions, leading to life-threatening responses.
