01 Answers Study Guide Qs Type I Hypersensitivity 24-06-10 (copy)

Type I Hypersensitivity

Exaggerated immune response causing damage

Mast cells

Located in connective tissues and mucus membranes; Basophils are in circulation

Eosinophils

Play a role in late stage of Type I hypersensitivity, activated to secrete major basic protein which activates mast cells

IL-5

Promotes activation, production, and recruitment of eosinophils

IgE

Required for Type I hypersensitivity response; IL-4 is needed for B cells to switch to IgE; Takes 12-14 days for IgE antibodies to be generated

IgE location

On mast cells bound to FcεR in non-atopic patients; On mast cells and in circulation in atopic patients and those with parasitic infections

IL-4

Cytokine required for Th0 cell to differentiate to Th2 cell

Reciprocal regulation of Th1 and Th2 cytokines

IFNγ downregulates Th2 cytokines; IL-4 downregulates Th1 cytokines

Hygiene hypothesis

Hygienic environment affects development of Th1 cytokines in response to infectious agents

Desensitization

A therapeutic intervention that aims to reduce sensitivity to allergens by exposing the patient to increasing doses of the allergen to generate plasma cells secreting IgG instead of IgE.

Anti-IgE antibodies

Therapeutic interventions that prevent IgE from binding to FcεR on mast cells, reducing the allergic response.

Sodium cromoglycate

A therapeutic intervention that stabilizes mast cells to prevent degranulation.

Anti-histamine

A therapeutic intervention that prevents histamine from binding to its receptor, reducing mucus secretion, vasodilation, and vascular permeability.

5-lipoxygenase inhibitor

Blocks the activity of 5-lipoxygenase, inhibiting the formation of leukotrienes.

Leukotriene receptor antagonist/blocker

Inhibits the binding of leukotrienes to their receptors.

Steroids

Therapeutic interventions that inhibit PLA2, leukotriene, and prostaglandin formation, preventing eosinophil attraction, increased vascular permeability, and smooth muscle contraction.

Anti-IL-5 antibody

Blocks circulating IL-5, preventing its binding to IL-5R and the production, recruitment, and activation of eosinophils.

Anti-IL-5 receptor antibody

Prevents the binding of IL-5 to its receptor, inhibiting eosinophil production, recruitment, and activation.

Anti-IL-4 antibody

Minimizes the differentiation of naïve T cells to Th2 cells, reducing the production of IL-5 and IL-4 cytokines.

Skin Test

A medical procedure used to determine allergens causing symptoms by introducing different allergens into the skin and observing reactions.

Wheal and Flare

Clinical terms used to describe the manifestation of local edema and local erythema in response to allergens introduced into the skin.

Anaphylaxis

A severe, potentially life-threatening allergic reaction that can occur rapidly after exposure to an allergen.