Question 1

Which of the following best describes a Type I hypersensitivity (anaphylactic) reaction?

Accepted Answer

It is an immediate reaction mediated by IgE antibodies binding to mast cells, causing degranulation and release of histamine.

Question 2

A patient receives a blood transfusion with the wrong blood type and develops fever, chills, and hemoglobinuria. Which immune mechanism is primarily responsible for this reaction?

Accepted Answer

Type II cytotoxic hypersensitivity

Question 3

Which of the following best explains the hygiene hypothesis?

Accepted Answer

Reduced exposure to microbes in early childhood leads to increased susceptibility to allergies and autoimmune diseases.

Question 4

A newborn develops jaundice and anemia due to maternal antibodies attacking fetal red blood cells. This is an example of:

Accepted Answer

Hemolytic disease of the newborn, a Type II cytotoxic reaction

Question 5

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

Accepted Answer

Deposition of antigen-antibody complexes in tissues, leading to inflammation

Question 6

A patient develops a red, itchy rash after contact with poison ivy. Which immune mechanism is responsible?

Accepted Answer

Type IV delayed cell-mediated hypersensitivity

Question 7

Which of the following best describes an allograft?

Accepted Answer

A tissue graft between two individuals of the same species who are not genetically identical

Question 8

Which of the following is a privileged site in the human body?

Accepted Answer

The cornea

Question 9

Which of the following best explains why immunosuppressive drugs are used in transplant recipients?

Accepted Answer

To prevent the recipient's immune system from attacking the transplanted tissue

Question 10

Which of the following is a potential side effect of immunosuppressive therapy in transplant patients?

Accepted Answer

Increased risk of infections and cancer

Question 11

Which of the following statements about HIV structure is correct?

Accepted Answer

HIV is a retrovirus with RNA genome and uses reverse transcriptase to synthesize DNA.

Question 12

Which of the following best describes the role of gp120 and gp41 in HIV infection?

Accepted Answer

They are viral proteins that facilitate fusion with the host T helper cell membrane.

Question 13

A patient with HIV is asymptomatic but has persistent lymphadenopathy. According to the stages of HIV infection, this patient is in:

Accepted Answer

Stage 1

Question 14

Which of the following is a criterion for the diagnosis of AIDS?

Accepted Answer

CD4+ T cell count below 200 cells/\mu L

Question 15

Which of the following best explains why HIV is difficult to eradicate from the body?

Accepted Answer

HIV integrates its genome into host DNA and has a high mutation rate.

Question 16

Which of the following is a real-world example of a Type IV cell-mediated autoimmune disease?

Accepted Answer

Type I diabetes mellitus

Question 17

Which of the following best describes the benefit of the normal microbiome for the immune system?

Accepted Answer

It helps train the immune system and prevents colonization by pathogens.

Question 18

A patient with dysbiosis is treated with a fecal transplant. What is the primary goal of this therapy?

Accepted Answer

To restore a healthy balance of gut microbiota

Question 19

Which of the following best describes the difference between pluripotent and multipotent stem cells?

Accepted Answer

Pluripotent stem cells can differentiate into any cell type, while multipotent stem cells are limited to a specific lineage.

Question 20

Which of the following is a challenge in developing an effective HIV vaccine?

Accepted Answer

HIV rapidly mutates, leading to antigenic variation.

Diseases of the Immune System: Hypersensitivities, Autoimmunity, Transplantation, and HIV/AIDS

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