Alterations in Immune Function

Vocabulary practice flashcards covering hypersensitivity types I-IV, pharmacological interventions, epinephrine administration, and autoimmune mechanics.

Hypersensitivity

A normal immune response that is inappropriately triggered, excessive, and produces undesirable effects on the body when encountering a 'harmless' environmental molecule.

Antigen

A protein or carbohydrate structure that the immune system recognizes as foreign, triggering an immune response.

B-lymphocytes

Lymphocytes that produce specific antibodies or immunoglobulins to bind, neutralize, or destroy matching antigens.

Cytotoxic T-cells (CD8)

T-lymphocytes equipped with T-cell receptors that are toxic to specific cells.

Helper T-cells (CD4)

T-lymphocytes that assist other immune cells, including B-cells.

Type I Hypersensitivity

An immediate, IgE-mediated reaction occurring within 15 to 20 minutes after exposure to an antigen in a previously sensitized individual.

Mast Cell Degranulation

The process in Type I hypersensitivity where antigen binding to attached IgE antibodies triggers mast cells to dump intracellular contents, primarily histamine, into tissues.

Histamine

An inflammatory chemical mediator released by mast cells that causes potent vasodilation, increased vascular permeability, bronchial smooth muscle constriction, and stimulation of irritant receptors.

Type I Hypersensitivity Clinical Manifestations

Summary of mediator activities and resulting manifestations including stuffy nose, lower blood pressure, skin wheals, edema, runny nose, breathing difficulties, wheezing, and pruritus.

Type II Hypersensitivity

A cytotoxic or antibody-mediated response where IgG or IgM antibodies attach to cell-surface antigens, causing direct cell destruction via lysis or phagocytosis.

Erythroblastosis Fetalis

A Type II hypersensitivity disorder occurring when an Rh-negative woman becomes sensitized to Rh-positive fetal blood cells, causing maternal antibodies to attack fetal red blood cells in a subsequent Rh-positive pregnancy.

Type III Hypersensitivity

An immune complex-mediated reaction where soluble IgG or IgM antigen-antibody complexes deposit into tissues, activating complement and recruiting neutrophils that release tissue-damaging enzymes.

Arthus Reaction

A localized Type III hypersensitivity pathology occurring in the skin following immune complex deposition and resultant local inflammation.

Type IV Hypersensitivity

A cell-mediated, delayed reaction involving no antibodies, driven by helper and cytotoxic T cells releasing cytokines and activating macrophages.

Haptens

Small, incomplete antigens that penetrate the skin and bind to serum proteins to form complete antigens recognized by antigen-presenting cells.

Summary of Hypersensitivity Types

Comparison chart of hypersensitivity reactions listing immune reactants, antigen forms, activation mechanisms, and clinical examples for Types I through IV.

Antihistamines

Medications that manage allergic responses by stabilizing mast cells to block mediator release or acting as antagonists at H1 and H2 histamine receptors.

Epinephrine

An adrenergic agonist and sympathomimetic agent acting on alpha and beta receptors to cause vasoconstriction, bronchodilation, and inhibition of mast cell mediator release during anaphylaxis.

EpiPen Administration Technique

Step-by-step instructions for auto-injector delivery: hold blue to sky, pull blue cap off, place orange tip at 90 degrees against outer thigh, swing and push into thigh until clicking, hold for 3 seconds, and massage area for 10 seconds.

Central Tolerance

The immunological process where self-reactive T and B lymphocytes are recognized and eliminated within primary lymphoid tissues and organs.

Peripheral Tolerance (Anergy)

A protective mechanism that functionally inactivates self-reactive lymphocytes that escape central tolerance.

Antigenic Mimicry

A mechanism of autoimmunity where foreign bacterial or viral antigens resemble self-antigens, leading the immune system to mistakenly attack self-tissues following an infection.

Immunosenescence

The gradual decline in immune system function associated with advancing age, serving as a risk factor for autoimmune conditions.