Immune System Disorders

Flashcards for key vocabulary related to immune system disorders, including immunodeficiencies, autoimmunity, and hypersensitivities.

Immunodeficiency

Lack of a properly functioning immune system.

Autoimmunity

Immune responses directed toward self.

Hypersensitivity

Excessive or inappropriately directed immune responses, sometimes including autoimmunity.

Primary Immunodeficiency

Immunodeficiency present from birth and genetic in nature.

Secondary Immunodeficiency

Acquired immunodeficiency due to infections, chronic illnesses, medications, or environmental factors.

Autoimmune Disorder

Failure of self-tolerance leading to immune responses against tissues, resulting in chronic conditions.

Autoantibodies

Antibodies that suggest autoimmune disease is present or likely to develop.

Monoclonal Antibodies

Highly specific antibodies directed against the specific immune system component causing the problem in autoimmune disorders; often referred to as biologics.

Hypersensitivity

Inappropriate, exaggerated immune response to harmless antigens, sometimes self-antigens.

Allergy (Type I Hypersensitivity)

Involves overproduction of IgE antibodies directed against harmless substances (allergens) and excessive histamine production.

Sensitization

Initial exposure to an allergen required for IgE production in Type I hypersensitivity.

Systemic Anaphylaxis

A system-wide allergic reaction that can be rapidly fatal, leading to throat swelling, fluid in lungs, and shock.

Wheal and Flare

Raised lesion (wheal) and reddened area (flare) measured in allergy challenge tests.

Desensitization immunotherapy

Injections of allergen in a controlled setting over months to trigger IgG production to 'soak up' allergen before it interacts with IgE.

Hygiene Hypothesis

Theory suggesting that reduced exposure to microbes in industrialized countries contributes to increased allergies.

Type II Hypersensitivity

"Cytotoxic" reactions involving IgG binding to cell surfaces, triggering complement system or NK cells to destroy antibody-bound cells.

ABO Blood Transfusion Reactions

Occur when antibodies are made against carbohydrate chains (A or B) found on red blood cells of different blood types, leading to cell destruction if the wrong type is transfused.

Hemolytic Disease of the Newborn

Triggered by Rh incompatibility between mother and fetus; Rh-negative mothers carrying Rh-positive babies are at risk.

Rhogam

Anti-Rh factor given to Rh-negative mothers to prevent them from making antibodies against Rh+ fetal antigens.

Type III Hypersensitivity

Immune complex formation of soluble antigens + IgM/IgG antibodies, which deposit in tissues and trigger complement/inflammation.

Type IV Hypersensitivity

Delayed hypersensitivity involving T cells reacting to harmless substances or self-antigens, with onset 12-72 hours after exposure.