Diseases of the Immune System - Nelson

Question 1

What are the two branches of the Adaptive Immune System?

Answer 1

Humoral Immunity

Cellular Immunity

Question 2

What is the function of the immune system?

Answer 2

To protect against harmful microorganisms and cellular agents (malignant cells)

Question 3

Define Immunodeficiencies

Answer 3

Disorders with decrease or loss of immune function, either acquired or congenital

Question 4

What are Hypersensitivity Reactions and what are the 2 types of having TOO MUCH immunity?

Answer 4

Disorders with pathologic immune responses or reactions
Allergic Reactions
Autoimmune Reactions

Question 5

Type I Hypersensitivity

Answer 5

Too much IgE crosslinking in response to environmental antigen leading to mast cell and basophil release of histamine, causing synthesis of prostaglandins and leukotreines, such as hay fever, asthma, hives, food allergies, and eczema.

Question 6

Type II Hypersensitivity

Answer 6

IgG or IgM Mediated Autoimmunity due to antibodies that react against self, such as hemolytic disease of maternal antibodies reacting to fetal RBCs, Myasthenia Gravis (AChR antibodies), and Good Pasture’s Syndrome (Basement membrane antibodies causing nephritis).

Question 7

Type III Hypersensitivity

Answer 7

Immune complexes of antigen and antibody that get stuck in small vessels, such as the kidneys, joints, pleura and skin. Complement is activated to respond to the antigen-antibody complex and healthy tissues are destroyed in the process, which happens in Lupus (making antibody to own DNA) and RA (making antibody to antibody); serum sickness, necrotizing vasculitis.

Question 8

Type IV Hypersensitivity

Answer 8

Cell-mediated hypersensitivity caused by activated CD4+ Th1 T-Cells (autoimune or innocent bystander injury); Contact hypersensitivity, TB reactions, Granulomatous hypersensitivity

Question 9

Humoral Immunity

Answer 9

B-cells that protect extracellular spaces release antibodies into bodily fluids.

Question 10

Cell-Mediated Immunity

Answer 10

T-cells that survey surfaces of cells, looking for mutated cells or parasites.

Question 11

Define Innate Immunity

Answer 11

Pre-existing defense mechanisms present prior to infection

Question 12

Define Adaptive Immunity

Answer 12

Reactive immune mechanisms that are stimulated by microbes or other foreign antigens

Question 13

Function of B Lymphocytes

Answer 13

Neutralization of microbe, phagocytosis, complement activation

Question 14

Function of Helper T Lymphocytes (CD4+)

Answer 14

Activation of macrophages
Inflammation
Activation (proliferation and differentiation) of T and B lymphocytes

Question 15

Function of Cytotoxic T Lymphocytes (CD8+)

Answer 15

Killing infected cells

Question 16

Function of Regulatory T Lymphocytes

Answer 16

Suppression of Immune Response

Question 17

Function of Natural Killer cells

Answer 17

Killing infected cells

Question 18

Define Generative (Primary) Lymphoid Organs

Answer 18

Sites where T (Thymus) and B (Bone Marrow) lymphocytes mature

Question 19

Define Peripheral (Secondary) Lymphoid Organs

Answer 19

Site where the adaptive immune response is initiated (lymph nodes, spleen)

Question 20

Class I MHC Molecules

Answer 20

coded by HLA-A, HLA-B, and HLA-C genes and display antigens to CD8+ T-cells and NK cells

Question 21

Class II MHC Molecules

Answer 21

coded by HLA-DP, HLA-DQ, HLA-DR genes and display antigents to CD4+ T-cells

Question 22

What are two uses for HLA testing?

Answer 22

1) determine disease risk

2) transplantation workup

Question 23

What is light chain restriction?

Answer 23

Monoclonal B-cells typically express only one type of immunoglobulin, either kappa or lambda.

Question 24

How can monoclonal light chain restriction be detected?

Answer 24

Flow cytometry - should be 1.5 kappa to lambda
Serum protein electrophoresis
Immunofixation electrophoresis
Kappa and lambda in situ hybridization - staining looking for proportions

Question 25

What are the 5 pillars of cancer treatment?

Answer 25

``` Surgery Chemotherapy Radiation Therapy Molecular Targeted Therapy Imatinib and Trastuzumab Target cancer cells by homing in on specific molecular changes seen primarily in those cells Immunotherapy T-cells to attack the tumor ```

Question 26

Define Hypersensitivity Reactions

Answer 26

Sensitization to previous exposure to antigen and when re-exposed, pathologic immune reactions ensue with excessive, injurious reaction to the antigen

Question 27

What does a hypersensitivity reaction usually result from?

Answer 27

Imbalance between effector mechanisms of immune response and control mechanism to limit response

Question 28

What do eosinophils release in a type I hypersensitivity reaction?

Answer 28

Major Basic Protein and Eosinophil Cationic Protein = Toxic to epithelial cells

Question 29

Define Atopy

Answer 29

Predisposition of developing immediate hypersensitivity reactions; 50% correlated with positive family history; higher serum levels of IgE and more Il-4 producing Th2 cells

Question 30

Describe the immediate type I hypersensitivity reaction

Answer 30

Exposure to allergen --> Th2 response and IgE production --> IgE binds to Fc on Mast Cells --> Re-exposure to allergen leads to mast cell degranulation Causes: Vasodilation Vascular Leakage Smooth Muscle Spasm

Question 31

Describe the late phase type I hypersensitivity reaction

Answer 31

Eosinophil infiltration with neutrophils and T-cells Causes: Leukocyte Infiltration Epithelial Damage Bronchospasm

Question 32

Describe immediate hypersensitivity reactions with non-atopic allergies

Answer 32

Exercise or temperature induced, not mediated by T-cells or IgE

Question 33

Immediate Type I Hypersensitivity Systemic Anaphylaxis

Answer 33

Life threatening systemic allergic reaction with falling BP, vascular shock, bronchospasm, laryngeal edema and difficulty breathing due to massive mast cell activation

Question 34

What are the two mechanisms for T-cell Mediated Type IV Hypersensitivity?

Answer 34

CD4+ T-Cell Mediated Inflammation | CD8+ T-Cell Mediated Cytotoxicity

Question 35

Define Graulomatous inflammation

Answer 35

A distinctive pattern of chronic inflammation via strong activation of T-cells leading to activated macrophages resulting in tissue injury.

Question 36

What is a granuloma?

Answer 36

A focus of chronic inflammation consisting of a microscopic aggregation of macrophages that are transformed into epithelial-like cells called histiocytes; may also fuse to form multi-nucleated giant cells

Question 37

What causes granulomas to form?

Answer 37

Immune reactions or reaction to foreign material

Question 38

Foreign Body Granulomas

Answer 38

See foreign material within histiocytes or giant cells

Question 39

Caseating Granulomas

Answer 39

Granulomas that induce cell-mediated immune response with central necrosis; usually associated with infection (mycobacterial and fungal infections)

Question 40

Non-Caseating Granulomas

Answer 40

Granulomas that induce cell-mediated immune response without central necrosis (sarcoidosis, Crohn's disease)