Chapter 12: Disorders of the Immune Responses Including HIV/AIDS

Question 1

Learning Objectives

Answer 1

By the end of class, the student will be able to
Define autoimmune diseases as primary or secondary.
Differentiate the four categories of autoimmune disorders.
Define four types of hypersensitivity disorders and treatment.
Discuss the pathophysiology of HIV infection and AIDS.

Question 2

Immunodeficiency

Answer 2

absolute or partial loss of normal immune response

Question 3

Primary Immunodeficiency

Answer 3

inherited- the underlying genetic defect is present as birth

Question 4

Secondary Immunodeficiency

Answer 4

develop sometime later in life in response to another disease entity or condition.

ex: malnutrition, acquired immunodeficiency syndrome [AIDS])or neoplastic (cancerous) diseases like lymphoma
or it can be from immunosuppressive therapy like corticosteroids or some transplant rejection medications.

Depending on the extent of any or all of the components that are compromised dictates the severity of the immunodeficiency.

Question 5

4 major categories of immune mechanisms

Answer 5

Humoral or antibody-mediated immunity (B lymphocytes)

Cell-mediated immunity (T lymphocytes)

The complement system

Phagocytosis (neutrophils and macrophages)

Question 6

Immunodeficiency and Infectious Organisms Table

Answer 6

B cell–mediated immunodeficiency disorders:
- affect antibody production which inhibits the ability of the immune system to defend against bacterial infections and toxins that circulate in body fluids
- affecting the IgM and IgG. Also enter the body through the mucosal surface of the respiratory or gastrointestinal tract (would involve IgA).
- examples: strep pneumoniae, staph aureaus, h influenzae

T cell–mediated immunodeficiency disorders:
- caused by problems with the T-cell receptor (TCR) complex, defective cytokine production, and defects in T-cell activation.
- impairs the immune systems ability to protect against fungal, protozoan, viral, and intracellular bacterial infections.
- ex: herpes virus and salmonella.

Combined T- and B-cell immunodeficiency disorders:
- affect all aspects of immune system and its function.
- bunch of bacteria listed and ALL the viruses.
- ((complement system and phagocytic cells)) are important components of innate immunity and can also be targeted in immunodeficiency disorders. Deficiencies in complement proteins can lead to enhanced susceptibility to infectious diseases and autoimmune disorders like SLE or lupus. People with phagocytic disorders are extremely susceptible to bacterial and fungal infections.
—-
Most of the b cell effects relate to bacterial issues

Question 7

Hypersensitivity Disorders

Answer 7

Excessive or inappropriate activation of the immune system

Question 8

Types of hypersensitivity

Answer 8

Type I IgE-mediated disorders
Type II Antibody-mediated disorders
Type III Complement-mediated immune disorders
Type IV T-cell–mediated disorders

Question 9

Type I hypersensitivity

Answer 9

Type I/IgE-mediated reactions:
- develop rapidly with exposure to an antigen. (the antigens are referred to asallergens)
– can be Environmental, medical, and pharmaceutical allergens, pollen proteins, house dust mites, animal dander, foods, household chemicals, and pharmaceuticals like penicillin.
– Exposure to the allergen can be through inhalation, ingestion, injection, or skin contact.
- Depending on the portal of entry, type I reactions may be localized to a specific area of the body (e.g., contact dermatitis) or it can be systemic causing significant disease (e.g., asthma) or life-threatening anaphylaxis.

Allergic Response:
Helper T –>
IgE (B lymphocyte) –>
Mast cell: degranulation  histamine, leukotrienes –>
Eosinophils (WBCs) migrate to the site –>
Prostaglandins

Histamines lead to increased vasodilation, lowererd BP, increased HR, vascular
Permeability (airway swelling)

Local: hives rash (urticaria),
Rhinitis, asthma