Process of Altering Immune Function

A comprehensive set of flashcards covering key concepts related to the immune system, altered immunity, hypersenstitivity reactions, autoimmunity, and other related topics from the provided lecture notes.

What is the main consequence of failure in host defense mechanisms?

Impaired ability to mount an immune defense, leading to increased risk of disease and death.

What does altered immunity result from?

Failure of host defense mechanisms, hypersensitivity, autoimmunity, and alloimmunity.

What is hypersensitivity?

Inappropriate immune responses that may be excessive.

Define autoimmunity.

Inappropriate immune response to the body's own tissues.

What is alloimmunity?

Reactions directed at tissue antigens from other individuals of the same species.

What is antigenic variation?

The ability of pathogens to change their antigens to evade detection by the immune system.

Why do people suffer from the same cold multiple times?

Pathogens can evade detection by going into latency.

How does Mycobacterium tuberculosis evade immune destruction?

It uses immune cells as host cells to prevent destruction.

What characterizes primary immunodeficiency?

Often caused by genetic mutations impairing immune responsiveness.

What is secondary immunodeficiency?

Immunodeficiency resulting from another disease.

List factors involved in immunodeficiency.

Defective humoral function, deficient phagocyte numbers, altered T lymphocyte signaling, and altered cytokine production.

What results from insufficient immune response?

Overwhelming infections may occur.

What is X-linked agammaglobulinemia also known as?

Bruton disease.

What is common variable immune deficiency (CVID)?

Hypogammaglobulinemia with normal B-cell numbers but impaired function.

What characterizes selective IgA deficiency?

Low levels of IgA with a normal number of B cells.

Describe severe combined immune deficiency.

A complete lack of immune defense involving both T and B cells.

What is the DiGeorge anomaly?

Condition characterized by an underdeveloped thymus and decreased circulating T cells.

What is the result of X-linked hyper-IgM syndrome?

Absent IgA and increased IgM, with non-functional T cells.

What is Wiskott-Aldrich syndrome?

A condition involving eczema, immune deficiency, and hemolytic anemia.

Describe ataxia-telangiectasia.

A rare disorder with increased sensitivity to radiation and ataxia.

What is chronic granulomatous disease?

A primary immunodeficiency characterized by impaired phagocytosis.

What are hypersensitivity reactions?

Disorders that result from excessive immune responses to allergens.

What are common triggers for type I hypersensitivity reactions?

Inhaled allergens, certain foods, and insect stings.

What is anaphylaxis?

A severe systemic allergic reaction that can be life-threatening.

List four major types of hypersensitivity reactions.

Type I, Type II, Type III, and Type IV reactions.

What is hypersensitivity classified based on?

Activated immune cells and the mechanism of damage.

What is the main immune cell involved in Type I hypersensitivity?

IgE mediated response involving mast cells and basophils.

Describe the symptoms of type I immediate hypersensitivity reactions.

Symptoms can include itching, swelling, and respiratory distress.

What is the role of mast cells in hypersensitivity reactions?

Mast cells release chemical mediators that cause tissue injury.

What are common allergens associated with type I hypersensitivity?

Pollen, dust, certain foods like peanuts and shellfish.

Define the sensitization phase in type IV hypersensitivity reactions.

The initial phase where an antigen is presented to T lymphocytes leading to memory cell formation.

What does the elicitation phase in type IV hypersensitivity reactions involve?

Memory T lymphocytes responding to previously recognized antigens.

What is autoimmune disease?

A failure of the immune system to distinguish between self and non-self, leading to tissue damage.

Give an example of organ-specific autoimmune disease.

Graves disease affecting the thyroid gland.

What is systemic lupus erythematosus (SLE)?

An autoimmune disease characterized by antibodies against multiple body tissues.

What might trigger autoimmunity?

Inadequate clearance of self-reactive lymphocytes or foreign mimicking self-antigens.

What are alloantigens?

Proteins that vary between individuals, prompting an immune response in another individual.

What is graft rejection?

An immune response against transplanted tissue due to incompatible MHC molecules.

How does graft-versus-host disease (GVHD) occur?

Donor T lymphocytes attack recipient tissues because they recognize them as foreign.

What are the two types of reactions in type IV hypersensitivity?

Direct cell-mediated cytotoxicity and delayed hypersensitivity reactions.

What is hypersensitivity caused by?

An exaggerated immune response to allergens.

Describe the main feature of type II antibody-mediated hypersensitivity.

It's a tissue-specific response where antibodies target and destroy cells.

What should be done to prevent type II hypersensitivity reactions?

Avoidance of the offending antigen, such as specific medications.

What is vasodilation related to in immediate hypersensitivity?

Initial reaction from mast cell degranulation leading to increased blood flow.

What happens during a type III immune complex-mediated reaction?

Antigen-antibody complexes activate complement, causing tissue damage.

What is a common condition associated with type III reactions?

Serum sickness following exposure to horse serum.

How does GVHD present clinically?

Characterized by rash, diarrhea, and liver dysfunction.

What role do regulatory T cells play in autoimmunity?

They suppress autoreactive lymphocytes and help regulate the immune response.

What is one method used for allergy testing?

Skin prick test to identify specific allergens.

What treatment can be effective for type I hypersensitivity reactions?

Venom immunotherapy for insect stings.

How is Rh isoimmunization related to type II hypersensitivity?

It results from an immune response to Rh antigens in a naive individual.

What is contact dermatitis?

A delayed hypersensitivity reaction resulting from skin exposure to an allergen.

Identify a factor that impacts the likelihood of graft acceptance.

The matching of MHC molecules between donor and recipient.

What does the presence of alloantibodies lead to in graft rejection?

Rapid hyperacute rejection of transplanted tissue.

Outline the importance of matching in allografts.

To reduce the risk of an immune response against transplanted tissue.

Why are grafts from monozygotic twins generally accepted?

They have identical genetic composition, leading to similar MHC molecules.

What impact does a decrease in neutrophils have on immune defense?

Increased susceptibility to bacterial infections.

What occurs with decreased macrophage numbers?

Impaired phagocytosis and antigen presentation.

What is the effect of reduced plasma cell numbers?

Decreased antibody production.