Immunopathology: Hypersensitivity Overview

An exaggerated or inappropriate immune response that damages the host's tissues.

An immediate hypersensitivity reaction mediated by IgE, activating mast cells.

Hypersensitivity reaction mediated by IgG, targeting cell-surface or matrix antigens, using complement and Fc receptors for attack.

Hypersensitivity reaction mediated by IgG directed against soluble antigens, forming immune complexes that trigger inflammation.

T cell-mediated hypersensitivity. Subdivided into three groups causing damage via macrophages (TH1), eosinophils (TH2), or cytotoxic T cells (CTL).

High-affinity receptors for IgE on mast cells, eosinophils, and basophils; crucial for Type I hypersensitivity.

Triggered by cross-linking FcεRI receptors via allergens bound to IgE antibodies.

Eosinophils, attracted by eotaxin, are a key player in allergic asthma.

Eosinophils release specific molecules during activation.

Allergic reactions and susceptibility are inheritable and greatly influenced by the surrounding environment.

An allergic reaction causing inflammation through the release of chemicals when allergens interact with IgE-sensitized mast cells.

Hay fever; an allergic reaction in the nasal passages and conjunctiva triggered by airborne allergens.

A severe and potentially life-threatening allergic reaction affecting the whole body, leading to low blood pressure and difficulty breathing.

Family history increases the likelihood of developing allergies. Conversely, if neither parent has allergies, the likelihood decreases.

Exposure to infectious agents early in life tends to promote a TH1 response, reducing the risk of allergies.

An immune reaction where antibodies target cells or tissues, leading to their destruction.

A condition where the immune system destroys red blood cells, leading to anemia.

A type of anemia caused by the immune system attacking red blood cells.

A condition where a mother's antibodies attack her baby's red blood cells due to Rh incompatibility.

Destruction of cells by activating a complement cascade via antibody binding.

A process where antibodies trigger the destruction of targeted cells by other immune cells.

An incompatibility between the blood types of a mother and her child, due to different Rh factors.

The amount and way allergens enter the body determine the type of IgE-mediated allergic reaction.

A local type III hypersensitivity reaction, slower than Type I, maximal at 4-8 hours, and more diffuse.

Hypersensitivity reaction involving IgG antibodies forming immune complexes that trigger inflammation.

A lung condition triggered by inhaled antigen complexes with IgG, leading to type III hypersensitivity.

T cell-mediated hypersensitivity reaction, maximal 48-72 hours later.

Cell that takes up antigen, processes it, and displays relevant fragments on MHC class II to T cells.

A type of T cell activated by APC-presented antigen, producing cytokines to stimulate other immune cells.

Low-affinity receptor for IgG, crucial for Type III hypersensitivity, slower than type I.

An allergic reaction triggered by IgE antibodies, activating mast cells and releasing mediators.

Immune response where antibodies target cells for destruction, often by complement or other cells.

Immune response where antigen-antibody complexes deposit in tissues, triggering inflammation and damage.

Immune reaction where T cells trigger inflammatory responses and tissue damage, often recruiting macrophages.

Clumping of activated macrophages in response to persistent antigens, often in chronic infections.

Secretion of signaling molecules by immune cells to regulate immune responses and inflammation.

A type of immune response that takes 48-72 hours or 21-28 days to manifest.

An allergic reaction to contact with certain substances, like organic chemicals or poison ivy, that takes time to show up.

A delayed hypersensitivity skin test reaction to certain antigens like tuberculin, that causes local induration.

A collection of immune cells, including macrophages and giant cells, that forms in response to persistent antigens or foreign bodies, leading to hard tissue.

TH1 cells influence immune response.

Immune response mediated by T-cells and takes a few days to develop, unlike immediate hypersensitivity.

Granulomas can be formed by inert foreign materials or microorganisms like mycobacteria that cause cell-mediated immunity.