Q: Which of the following equations best represents the formation of an antigen-antibody complex in Type III hypersensitivity?

$$\text{Ag} + \text{Ab} \rightarrow \text{Ag-Ab complex}$$

Question 1

Which of the following best describes a primary immunodeficiency?

Accepted Answer

A genetically based disorder present at birth that limits immune function.

Question 2

A patient develops severe anemia after a second pregnancy due to maternal antibodies attacking fetal red blood cells. Which hypersensitivity type is this?

Accepted Answer

Type II (Cytotoxic) hypersensitivity

Question 3

Which of the following is a key feature of Type I hypersensitivity reactions?

Accepted Answer

IgE antibodies bind to mast cells, leading to degranulation upon allergen exposure.

Question 4

A patient receives a blood transfusion and develops fever, chills, and lower back pain within hours. What is the most likely cause?

Accepted Answer

Hemolytic transfusion reaction due to incompatible blood type (Type II hypersensitivity)

Question 5

Which of the following equations best represents the formation of an antigen-antibody complex in Type III hypersensitivity?

Accepted Answer

$$	ext{Ag} + 	ext{Ab} ightarrow 	ext{Ag-Ab complex}$$

Question 6

Which of the following is an example of a secondary immunodeficiency?

Accepted Answer

HIV infection leading to AIDS

Question 7

A patient with multiple sclerosis experiences T cell–mediated destruction of myelin. Which hypersensitivity type is involved?

Accepted Answer

Type IV (Delayed) hypersensitivity

Question 8

Which of the following best explains why a person with type O blood can donate to any ABO blood type?

Accepted Answer

Type O blood lacks A and B antigens, so recipient antibodies do not react.

Question 9

Which of the following is a real-world example of a nonautoimmune Type IV hypersensitivity reaction?

Accepted Answer

Tuberculin skin test (PPD test)

Question 10

Which of the following best describes the mechanism of action for monoclonal antibody immunotherapies in cancer treatment?

Accepted Answer

They target and bind specific antigens on cancer cells, marking them for immune destruction.

Question 11

Which of the following is NOT a feature of systemic anaphylaxis?

Accepted Answer

It is always limited to a single tissue or organ.

Question 12

Which of the following autoimmune diseases is primarily associated with Type III hypersensitivity?

Accepted Answer

Systemic lupus erythematosus

Question 13

A patient develops a rash after wearing latex gloves for several days. Which immune mechanism is most likely responsible?

Accepted Answer

Type IV (Delayed) hypersensitivity

Question 14

Which of the following best describes the difference between autoimmunity and allergy?

Accepted Answer

Autoimmunity targets self-tissues, while allergy targets harmless foreign antigens.

Question 15

Which of the following is a plausible outcome if a patient with type A blood receives type B blood?

Accepted Answer

Hemolytic transfusion reaction due to anti-B antibodies attacking donor cells.

Question 16

Which of the following best describes the role of complement proteins in Type II hypersensitivity?

Accepted Answer

They are activated by antibodies bound to cell surfaces, leading to cell lysis.

Question 17

Which of the following is a characteristic of Type IV hypersensitivity reactions?

Accepted Answer

They are mediated by T cells and manifest 12–72 hours after antigen exposure.

Question 18

Which of the following is a correct statement about the mnemonic 'ACID' for hypersensitivity types?

Accepted Answer

A = Allergy (Type I), C = Cytotoxic (Type II), I = Immune complex (Type III), D = Delayed (Type IV)

Question 19

Which of the following best explains why a person with DiGeorge syndrome is more susceptible to infections?

Accepted Answer

They have an underdeveloped or absent thymus, leading to low T cell numbers.

Question 20

Which of the following is a real-world example of a Type I hypersensitivity reaction?

Accepted Answer

Allergic rhinitis (hay fever)

Immune System Disorders: Immunodeficiencies, Autoimmunity, and Hypersensitivities

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