Question 1

According to the Hygiene Hypothesis, what is the primary consequence of limited early-life exposure to microbes?

Accepted Answer

Overreaction of the immune system to harmless antigens, leading to allergies and autoimmune diseases

Question 2

Which of the following conditions is most directly associated with microbial imbalance (dysbiosis) caused by antibiotic use?

Accepted Answer

Crohn’s disease

Question 3

A patient develops an autoimmune disease after the immune system loses self-tolerance. Which process best describes this mechanism?

Accepted Answer

The immune system attacks the body’s own cells (self-antigens), damaging tissues and organs

Question 4

Which of the following best differentiates congenital from acquired immunodeficiencies?

Accepted Answer

Congenital immunodeficiencies are present at birth due to defective or missing genes, while acquired develop later due to infections, drugs, or cancers

Question 5

Which mechanism allows HIV to evade the host’s antibodies most effectively during infection?

Accepted Answer

HIV remains latent as a provirus in host cell DNA

Question 6

HIV originated from SIV in chimpanzees. Which real-world scenario most accurately describes how HIV crossed into the human population?

Accepted Answer

Contact with infected bushmeat in West/Central Africa around 1908

Question 7

During which phase of HIV infection does the CD4 T cell count drop below 200 cells, leading to severe immune system damage and opportunistic infections?

Accepted Answer

Phase 3 – AIDS indicator conditions

Question 8

A patient with HIV is found to have a severely weakened immune system. Which cell type is primarily destroyed by HIV, leading to this vulnerability?

Accepted Answer

CD4+ helper T cells

Question 9

Which of the following is NOT a recognized route of HIV transmission?

Accepted Answer

Airborne droplets

Question 10

A mother infected with HIV is concerned about transmitting the virus to her child. Which of the following is a possible route of transmission from mother to child?

Accepted Answer

Transplacental transmission

Question 11

Which combination of prevention and treatment strategies is currently recommended for HIV infection?

Accepted Answer

Condom use and HAART (highly active antiretroviral therapy)

Question 12

A patient is exposed to HIV and seeks immediate medical intervention. Which treatment is most appropriate in this scenario?

Accepted Answer

PEP (post-exposure prophylaxis)

Question 13

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

Accepted Answer

HIV rapidly mutates its surface proteins and remains latent as a provirus in host cell DNA

Question 14

A patient with Crohn’s disease is found to have a history of frequent antibiotic use. Which concept best explains the link between antibiotic use and Crohn’s disease?

Accepted Answer

Antibiotics cause dysbiosis, an imbalance in the gut microbiota

Question 15

Which formula would you use to calculate the CD4+ T cell percentage in a blood sample if you know the total lymphocyte count and the CD4+ T cell count?

Accepted Answer

$$ 	ext{CD4+ T cell percentage} = \frac{	ext{CD4+ T cell count}}{	ext{Total lymphocyte count}} 	imes 100 $$

Question 16

A patient’s CD4+ T cell count is measured at 180 cells/µL. According to the stages of HIV infection, which phase is the patient most likely experiencing?

Accepted Answer

Phase 3 – AIDS indicator conditions

Question 17

Which scenario best illustrates the application of the Hygiene Hypothesis in a real-world context?

Accepted Answer

Children exposed to diverse microbes early in life have reduced risk of allergies and autoimmune diseases

Question 18

Which of the following is an example of an acquired immunodeficiency?

Accepted Answer

AIDS resulting from HIV infection

Question 19

Which method is NOT recommended for preventing HIV transmission?

Accepted Answer

Sharing needles among drug users

Question 20

A patient is diagnosed with an autoimmune disease. Which of the following best describes the immune system’s response in this condition?

Accepted Answer

The immune system attacks self-antigens, leading to tissue and organ damage

Chapter 19: Immunological Disorders and HIV Infection

Study Guide - Practice Questions

Study Guide - Flashcards