Exam 1 Practice Questions

A 25-year-old male presents with a bacterial infection. Describe the sequence of events from the initial infection to the resolution of the infection by the immune system. Include the roles of both the innate and adaptive immune responses.

Recognition of pathogen, activation of innate immune cells, antigen presentation, activation of adaptive immune cells, pathogen clearance, resolution.

Which of the following best describes the interaction between the innate and adaptive immune systems during an infection?

The innate immune system provides immediate defense and presents antigens to the adaptive immune system, which then generates a specific response.

Which of the following immune cells is derived from a common myeloid progenitor and what is its primary function?

Neutrophil; phagocytosis.

A patient with a genetic mutation lacks the cytokine IL-7. Which of the following immune cell types would be most affected by this deficiency?

B cells.

Which of the following statements correctly differentiates the roles of activated CD4 and CD8 T cells?

CD4 T cells help activate other immune cells, while CD8 T cells directly kill infected cells.

A 22-year-old female presents with a high fever, chills, and a productive cough. A sputum culture confirms a bacterial infection. Which of the following steps is the first in the immune system’s response to this infection?

Recognition of pathogen-associated molecular patterns (PAMPs) by toll-like receptors (TLRs)

A 35-year-old male presents with symptoms of a viral infection. Which of the following best describes how the innate and adaptive immune systems work together to generate an effective immune response?

Innate immune cells recognize the virus and produce cytokines to activate adaptive immune cells, which then target the virus specifically.

Which of the following correctly compares the innate and adaptive immune responses?

Innate immune response has no memory and is non-specific, while adaptive immune response has memory and is highly specific.

patient with a genetic mutation lacks functional IL-5. Which of the following immune cells would be most affected by this deficiency?

Eosinophils

A 40-year-old male presents with recurrent infections and is diagnosed with a deficiency in phagocyte function. Which of the following receptors is most likely involved in this deficiency?

Fc receptor

A 45-year-old man with end-stage renal disease receives a kidney transplant from his sister. What type of graft is this considered?

Allograft

A 30-year-old woman with severe burns undergoes a skin graft procedure using tissue from her thigh to cover wounds on her arm. What type of graft is this?

Autograft

A patient is scheduled for a corneal transplant. Which of the following tests is MOST important to perform prior to the procedure to ensure graft compatibility?

Tissue typing is not necessary for corneal transplants

A 50-year-old man receives a heart transplant. Two weeks after the procedure, he develops fever, fatigue, and signs of heart failure. Biopsy shows lymphocytic infiltration and myocyte damage. What type of rejection is this most likely?

Acute cellular rejection

A patient receives a kidney transplant and experiences rapid graft failure within hours of the procedure. Laboratory tests reveal preformed antibodies against donor HLA antigens. Which type of hypersensitivity reaction best describes this scenario?

Type II hypersensitivity

A bone marrow transplant recipient develops skin rash, diarrhea, and liver dysfunction 3 weeks after the procedure. What is the most likely diagnosis?

Graft-versus-host disease

A patient with cystic fibrosis undergoes a lung transplant. Six months later, she develops progressive dyspnea and declining lung function. Biopsy shows obliterative bronchiolitis. What type of rejection is this most likely?

Chronic rejection

A patient is being evaluated for a liver transplant. Which of the following tests is MOST important in determining the likelihood of finding a compatible donor?

ABO blood typing

A 55-year-old man receives a heart transplant. Prior to the transplant, which of the following tests is MOST important to predict the risk of hyperacute rejection?

Cross-matching

A patient develops chronic rejection of a transplanted kidney. Which of the following histological findings is MOST characteristic of this condition?

Arterial intimal fibrosis

bone marrow transplant recipient develops acute graft-versus-host disease (GVHD). Which of the following cells are primarily responsible for initiating this condition?

T cells from the donor

A 24-year-old man presents to the emergency department with a 2-day history of productive cough and fever. His temperature is 39.2°C (102.6°F). Shortly after arrival, he begins to shiver and complains of feeling "very cold," despite his elevated core temperature. Which of the following best explains the mechanism underlying his current symptoms?

Pyrogen-induced PGE₂ has raised the hypothalamic set point above his current core temperature

A 68-year-old man presents with recurrent pneumonia. He has a history of chronic lymphocytic leukemia (CLL) but is not currently on treatment. Which mechanism best explains his increased susceptibility to infections?

Hypogammaglobulinemia

A 45-year-old woman with rheumatoid arthritis on long-term methotrexate therapy develops severe herpes zoster. Which component of the immune system is most likely compromised by methotrexate?

T cells

A 30-year-old man with HIV presents with Pneumocystis jirovecii pneumonia. His CD4 count is 150 cells/μL. Which mechanism best explains the loss of CD4 T cells in HIV infection?

Chronic immune activation and exhaustion

A 55-year-old man who underwent splenectomy for trauma 10 years ago presents with severe sepsis caused by Streptococcus pneumoniae. Which immune function is most compromised in asplenic individuals?

Phagocytosis of encapsulated bacteria

A 40-year-old woman with myeloproliferative leukemia develops recurrent sinopulmonary infections. Which mechanism best explains her increased susceptibility to infections?

Neutropenia

A 25-year-old man presents with persistent oral candidiasis and weight loss. HIV testing is positive, and his CD4 count is 300 cells/μL. Which HIV protein plays a crucial role in viral entry into CD4 T cells?

gp120

A 60-year-old man with diabetes mellitus type 2 presents with recurrent skin and soft tissue infections. Which aspect of immune function is most likely impaired in poorly controlled diabetes?

Neutrophil function

A 3-year-old child presents with severe measles infection complicated by pneumonia. Which mechanism best explains the immunosuppression associated with measles virus infection?

Depletion of memory T and B cells

A 35-year-old woman with HIV presents with cryptococcal meningitis. Her CD4 count is 50 cells/μL. Which HIV-related mechanism most directly contributes to the depletion of uninfected bystander CD4 T cells?

Fas-mediated apoptosis

A 28-year-old woman with newly diagnosed HIV presents with oral thrush. Her CD4 count is 400 cells/μL. Which mechanism best explains the early susceptibility to opportunistic infections in HIV, even before severe CD4 depletion?

Depletion of tissue-resident memory CD4 T cells

A 25-year-old woman presents with recurrent skin abscesses and pneumonia. Flow cytometry reveals absent expression of CD18 on leukocytes. Which condition is most likely?

Leukocyte adhesion deficiency type 1

A 4-year-old boy presents with recurrent sinopulmonary infections and absent tonsils. Flow cytometry reveals absent CD19+ cells. Which condition is most likely?

X-linked agammaglobulinemia

A 25-year-old woman presents with recurrent Neisseria meningitidis infections. Laboratory tests show normal immunoglobulin levels and T cell counts, but decreased serum bactericidal activity. Which condition is most likely?

MAC deficiency

A 2-year-old girl presents with recurrent severe bacterial and fungal infections, partial albinism, and abnormal giant granules in her leukocytes. Which condition is most likely?

Chediak-Higashi syndrome

A 6-month-old boy presents with recurrent bacterial infections, chronic diarrhea, and failure to thrive. Flow cytometry reveals absent T cells and B cells. Which condition is most likely?

Severe combined immunodeficiency

A 10-year-old boy presents with recurrent sinopulmonary infections, eczema, and thrombocytopenia. He has a history of bloody diarrhea in infancy. Which condition is most likely?

Wiskott-Aldrich syndrome

A 20-year-old woman presents with recurrent respiratory infections and low serum IgG, IgA, and IgM levels. B cell numbers are normal, but they fail to differentiate into plasma cells. Which condition is most likely?

Common variable immunodeficiency

A 3-year-old boy presents with recurrent severe infections with catalase-positive organisms and poor wound healing. Neutrophil oxidative burst assay shows absent respiratory burst. Which condition is most likely?

Chronic granulomatous disease

A 2-year-old boy presents with recurrent skin abscesses, pneumonia, and eczema. He has a characteristic facies with a broad nasal bridge and retention of primary teeth. IgE levels are markedly elevated. Which condition is most likely?

Hyper IgE syndrome