Patho_notes_2d_immunity_disorders_II

Hypersensitivity

An exaggerated immune response to an antigen, classified into four types: Type I (Immediate), Type II (Ab-mediated cytotoxicity), Type III (Immune complex mediated), and Type IV (cell-mediated, delayed).

Type I Hypersensitivity

Immediate hypersensitivity reaction involving IgE and mast cells, leading to conditions like anaphylaxis and allergic reactions.

Mast cell degranulation

The process in which mast cells release histamine and other chemicals in response to an allergen, causing allergic symptoms.

Immune complex

Aggregation of antibodies and antigens that can deposit in tissues and trigger inflammation, characteristic of Type III hypersensitivity.

Type II Ab-mediated cytotoxicity

A form of hypersensitivity where antibodies bind to cell surfaces and trigger destruction via various immune mechanisms.

Cell-mediated, delayed type hypersensitivity (Type IV)

An immune response where T cells mediate chronic inflammation and tissue damage, often seen in infections and transplant rejections.

Opportunistic infections

Infections that occur more frequently and are more severe in individuals with weakened immune systems, such as those with SCID or AIDS.

AIDS-related complex (ARC)

A stage of HIV infection characterized by the presence of some symptoms like swollen lymph nodes and fatigue, but not yet full-blown AIDS.

Systemic lupus erythematosus (SLE)

An autoimmune disease affecting multiple organs, often diagnosed by specific criteria including the presence of anti-nuclear antibodies.

Type III hypersensitivity

A hypersensitivity reaction characterized by the formation of immune complexes that deposit in tissues, leading to inflammation and damage.

B-cell deficiencies

Genetic conditions where the body lacks adequate B cells, leading to immunodeficiency and increased vulnerability to infections.

SCID (Severe Combined Immunodeficiency)

A genetic disorder resulting in the absence of both T and B lymphocytes, leading to life-threatening infections.

Thymus dysfunction

A condition where the thymus gland, essential for T cell maturation, does not function properly, affecting immune responses.

Kaposi's sarcoma

A type of cancer that can occur in AIDS patients, characterized by the abnormal growth of blood vessels.

Autoimmune disease

A disorder where the immune system mistakenly attacks the body's own cells and tissues, which can be confined to a single organ or be systemic.

Positive anti-nuclear antibody

An indicator of autoimmune conditions, particularly systemic lupus erythematosus, where the immune system targets nuclear components.