Immunology

Question 1

What is transplantation?

Answer 1

The process of taking cells, tissue, or organs and placing them in another person.

Question 2

What is an Allograft?

Answer 2

Transplantation from one person to another.

Question 3

What is an Autograft?

Answer 3

Transplantation from the same person to the same person.

Question 4

What is a major complication of transplantation?

Answer 4

Graft rejection.

Question 5

What must the host’s immune system do for a transplant to succeed?

Answer 5

Recognize the transplant as ‘self’.

Question 6

Which immune cells help in recognizing foreign antigens during transplantation?

Answer 6

T-lymphocytes.

Question 7

What guides T-lymphocytes in distinguishing self from non-self?

Answer 7

HLA proteins on cell surfaces.

Question 8

What happens when B and T lymphocytes encounter unfamiliar peptides?

Answer 8

They attack the cells.

Question 9

How does the risk of rejection change with HLA similarity?

Answer 9

It decreases with greater HLA similarity between donor and recipient.

Question 10

What are primary immunodeficiency disorders (PIDDS)?

Answer 10

Abnormalities in the immune system that are inherited or congenital.

Question 11

What causes most PIDDS?

Answer 11

Deficiencies in the signaling pathway affecting cytokines, receptors, and metabolic pathways.

Question 12

What are secondary immunodeficiency disorders?

Answer 12

Disorders that are acquired later in life.

Question 13

What is often associated with PIDDS?

Answer 13

Autoimmunity.

Question 14

Name an example of a primary immunodeficiency disorder.

Answer 14

Selective deficiency of IgG, IgA, and IgM.

Question 15

What is DiGeorge syndrome?

Answer 15

Congenital thymic aplasia.

Question 16

What is a hereditary deficiency of complement proteins?

Answer 16

An example of a primary immunodeficiency disorder.

Question 17

What are hypersensitivity disorders?

Answer 17

Excessive or elevated responses from an active immune system that causes injury to the host tissue.

Question 18

How many types of hypersensitivity disorders are there?

Answer 18

Four types (Type I-IV).

Question 19

What are the four hypersensitivity reactions or types

Answer 19

Type 1 (IgE) mediated hypersensitivity disorders

Type 2 Antibody-Mediated disorders

Type 3 Immune complement mediated disorders

Type 4 T- Cell mediated hypersensitivity disorder

Question 20

What are autoimmune diseases?

Answer 20

Autoimmune diseases occur when the body cannot distinguish its own cells from foreign cells, leading to attacks on normal cells.

Question 21

What causes autoimmune diseases?

Answer 21

The exact cause is unknown, but both genetic and environmental factors play a role.

Question 22

Does gender affect autoimmune diseases?

Answer 22

Yes, Gender can have an effect on the type of autoimmune disorder.

Question 23

What is the pathophysiology of autoimmune diseases?

Answer 23

Autoimmune diseases involve the immune system mistakenly attacking the body’s own tissues, causing chronic inflammation and tissue damage.

Question 24

What are autoantibodies?

Answer 24

Autoantibodies are antibodies produced by the immune system that target and attack a person’s own tissues and antigens.

Question 25

What are common elements in autoimmune pathophysiology?

Answer 25

Common elements include autoantibodies, T-cell dysfunction, and molecular mimicry.

Question 26

How are autoimmune diseases diagnosed?

Answer 26

Diagnosis is based on evidence of autoimmunity indicated by history, physical, and serologic findings.

Question 27

What are typical symptoms of autoimmune diseases?

Answer 27

Typical symptoms include fatigue, joint pain and swelling, skin problems, abdominal pain or digestive issues, recurring fever, and swollen glands.

Question 28

What causes Type I hypersensitivity?

Answer 28

It is an IgE-mediated allergic reaction to harmless antigens (e.g., pollen, dust, food). Mast cells and basophils release histamine, leading to symptoms.

Question 29

What are the phases and symptoms of Type I hypersensitivity?

Answer 29

Initial phase (5–60 min): Vasodilation, vascular leakage, smooth muscle contraction. Secondary phase (2–8 hrs): Eosinophil infiltration. Symptoms: Hives, runny nose, asthma, atopic dermatitis, or life-threatening anaphylaxis.

Question 30

What are the main mechanisms of Type II hypersensitivity?

Answer 30

Complement-activated cell destruction (e.g., MAC). ADCC: Natural killer cells destroy targets via IgG. Complement-mediated inflammation (e.g., neutrophil degranulation). Receptor modulation: Antibodies alter receptor function (e.g., Graves' disease).

Question 31

What characterizes Type II hypersensitivity?

Answer 31

IgG/IgM antibodies attack antigens on host cells, leading to cell destruction or dysfunction. Seen in conditions like pemphigus vulgaris and Graves' disease.

Question 32

What causes Type III hypersensitivity?

Answer 32

Immune complexes (antigen-antibody) form in the bloodstream, deposit in tissues, activate complement, and trigger inflammation.

Question 33

What are the clinical effects of Type III hypersensitivity?

Answer 33

Causes vasculitis in autoimmune diseases like SLE and glomerulonephritis, affecting organs like kidneys, skin, lungs, and joints.

Question 34

What are the subcategories of Type IV hypersensitivity?

Answer 34

IVa: Macrophage activation (e.g., eczema). IVb: Eosinophil activation (e.g., delayed hypersensitivity). IVc: Cytotoxic T-cell response (e.g., hepatitis). IVd: Neutrophil activation (e.g., AGEP).

Question 35

What defines Type IV hypersensitivity, and what are the symptoms?

Answer 35

T-cell-mediated tissue damage, with symptoms like skin reactions (contact dermatitis), organ-specific inflammation, and tuberculin test responses.