Vascular changes in inflammation — MCQs

10 questions

A 2-year-old boy has a history of recurrent bacterial infections, especially of his skin. When he has an infection, pus does not form. His mother reports that, when he was born, his umbilical cord took 5 weeks to detach. He is ultimately diagnosed with a defect in a molecule in the pathway that results in neutrophil extravasation. Which of the following correctly pairs the defective molecule with the step of extravasation that molecule affects?

Two weeks after undergoing low anterior resection for rectal cancer, a 52-year-old man comes to the physician because of swelling in both feet. He has not had any fever, chills, or shortness of breath. His temperature is 36°C (96.8°F) and pulse is 88/min. Physical examination shows a normal thyroid and no jugular venous distention. Examination of the lower extremities shows bilateral non-pitting edema that extends from the feet to the lower thigh, with deep flexion creases. His skin is warm and dry, and there is no erythema or rash. Microscopic examination of the interstitial space in this patient's lower extremities would be most likely to show the presence of which of the following?

A 47-year-old man presents as a new patient at an outpatient clinic. He has never seen a physician before, but was motivated by his 40-year-old brother's recent heart attack and seeks to optimize his health. In particular, he read that uncontrolled atherosclerosis can lead to a heart attack. Which molecule is downregulated in response to the advent of atherosclerosis?

While playing in the woods with friends, a 14-year-old African-American male is bitten by an insect. Minutes later he notices swelling and redness at the site of the insect bite. Which substance has directly led to the wheal formation?

An 8-year-old boy is shifted to a post-surgical floor following neck surgery. The surgeon has restricted his oral intake for the next 24 hours. He does not have diarrhea, vomiting, or dehydration. His calculated fluid requirement is 1500 mL/day. However, he receives 2000 mL of intravenous isotonic fluids over 24 hours. Which of the following physiological parameters in the boy’s circulatory system is most likely to be increased?

A 48-year-old male dies in the intensive care unit following a severe Streptococcus pneumoniae pneumonia and septic shock. Autopsy of the lung reveals a red, firm left lower lobe. What would you most likely find on microscopic examination of the lung specimen?

A student is experimenting with the effects of nitric oxide in the body. He used a variety of amino acid isolates and measured the resulting nitric oxide levels and the physiological effects on the body. The amino acids function as substrates for nitric oxide synthase. After supplement administration, blood vessels dilated, and the systemic blood pressure decreased. Which of the following amino acids was used in this study?

A 67-year-old woman is admitted to the hospital because of a 2-day history of fever, headache, jaw pain, and decreased vision in the right eye. Her erythrocyte sedimentation rate is 84 mm per hour. Treatment with methylprednisolone is initiated but her symptoms do not improve. The physician recommends the administration of a new drug. Three days after treatment with the new drug is started, visual acuity in the right eye increases. The beneficial effect of this drug is most likely due to inhibition of which of the following molecules?

A 4-year-old Caucasian boy is brought by his mother to the pediatrician with a red and swollen elbow. He was playing outside a few days prior to presentation when he fell and lightly scraped his elbow on the sidewalk. He was born at 34 weeks' gestation and was in the neonatal ICU for 2 days. His temperature is 102.1°F (38.9°C), blood pressure is 105/65 mmHg, pulse is 110/min, and respirations are 20/min. On exam, he has a swollen, erythematous, fluctuant, and exquisitely tender mass on his right elbow. There is expressible purulence coming from his wound. A peripheral blood smear in this patient would most likely reveal which of the following findings?

Q10

A 32-year-old man who recently emigrated from Somalia comes to the physician because of a 4-week history of fever, cough, and chest pain. He has had a 5-kg (11-lb) weight loss over the last 3 months despite no changes in appetite. His temperature is 38.1°C (100.6°F). Physical examination shows enlarged cervical lymph nodes. The lungs are clear to auscultation. The results of an interferon-γ release assay are positive. An x-ray of the chest shows bilateral mediastinal lymphadenopathy. A transbronchial needle aspiration biopsy of a mediastinal lymph node is performed; a photomicrograph of the specimen is shown. The structure indicated by the arrow is most likely comprised of which of the following types of cells?

Vascular changes in inflammation US Medical PG Practice Questions and MCQs

Question 1: A 2-year-old boy has a history of recurrent bacterial infections, especially of his skin. When he has an infection, pus does not form. His mother reports that, when he was born, his umbilical cord took 5 weeks to detach. He is ultimately diagnosed with a defect in a molecule in the pathway that results in neutrophil extravasation. Which of the following correctly pairs the defective molecule with the step of extravasation that molecule affects?

A. E-selectin; transmigration
B. LFA-1 (integrin); tight adhesion (Correct Answer)
C. ICAM-1; margination
D. E-selectin; tight adhesion
E. PECAM-1; transmigration

Explanation: ***LFA-1 (integrin); tight adhesion*** - This patient's symptoms (recurrent bacterial infections, lack of pus formation, and delayed umbilical cord separation) are classic for **Leukocyte Adhesion Deficiency type 1 (LAD-1)**. - **LAD-1** is caused by a defect in the **CD18 subunit** of **β2 integrins**, including **LFA-1** and **Mac-1**, which are crucial for the **tight adhesion** of neutrophils to endothelial cells. *E-selectin; transmigration* - **E-selectin** mediates the initial **rolling** of leukocytes along the endothelial surface, not transmigration. - A defect in E-selectin would impair rolling, but the primary defect in LAD-1 is in tight adhesion. *ICAM-1; margination* - **ICAM-1** (Intercellular Adhesion Molecule-1) is an endothelial ligand that binds to integrins on leukocytes, facilitating **tight adhesion** and transmigration, not margination. - **Margination** refers to the movement of leukocytes to the periphery of the blood vessel lumen. *E-selectin; tight adhesion* - **E-selectin** is involved in the initial **rolling** phase of extravasation by binding to sialyl Lewis X on leukocytes. - It does not primarily mediate **tight adhesion**, which is facilitated by integrins binding to ICAM-1. *PECAM-1; transmigration* - **PECAM-1** (Platelet Endothelial Cell Adhesion Molecule-1) is primarily involved in **transmigration** (diapedesis), where leukocytes pass between endothelial cells. - While important for extravasation, the characteristic findings of LAD-1 point to a defect earlier in the pathway, specifically tight adhesion.

Question 2: Two weeks after undergoing low anterior resection for rectal cancer, a 52-year-old man comes to the physician because of swelling in both feet. He has not had any fever, chills, or shortness of breath. His temperature is 36°C (96.8°F) and pulse is 88/min. Physical examination shows a normal thyroid and no jugular venous distention. Examination of the lower extremities shows bilateral non-pitting edema that extends from the feet to the lower thigh, with deep flexion creases. His skin is warm and dry, and there is no erythema or rash. Microscopic examination of the interstitial space in this patient's lower extremities would be most likely to show the presence of which of the following?

A. Neutrophilic, protein-rich fluid
B. Lymphocytic, hemosiderin-rich fluid
C. Lipid-rich, protein-rich fluid (Correct Answer)
D. Protein-rich, glycosaminoglycan-rich fluid
E. Acellular, protein-poor fluid

Explanation: ***Lipid-rich, protein-rich fluid*** - The presentation of bilateral non-pitting edema extending to the thigh, with deep flexion creases, in a patient post-**low anterior resection** for rectal cancer, strongly suggests **lymphedema**. - Lymphedema results from impaired lymphatic drainage, leading to the accumulation of **protein-rich fluid**, **macromolecules**, and **adipose tissue** in the interstitial space, which eventually becomes lipid-rich due to chronic inflammation and fibroblasts stimulating adipogenesis. *Neutrophilic, protein-rich fluid* - This description is characteristic of **inflammatory edema** or **purulent exudate**, typically seen in infections. - The patient's lack of fever, chills, erythema, or warmth makes an infectious or acute inflammatory process unlikely. *Lymphocytic, hemosiderin-rich fluid* - **Hemosiderin deposits** are indicative of chronic **venous insufficiency** or recurrent hemorrhages, leading to red blood cell extravasation and breakdown. - While lymphocytes can be present in chronic inflammation, the primary issue here is lymphatic obstruction, not venous stasis or bleeding. *Protein-rich, glycosaminoglycan-rich fluid* - While lymphedema is indeed **protein-rich**, the primary accumulation in mature lymphedema involves **adipose tissue** and fibrosis. - **Glycosaminoglycans** accumulate significantly in conditions like **myxedema** (hypothyroidism), which was ruled out by the normal thyroid examination. *Acellular, protein-poor fluid* - This describes a **transudate**, typically seen in conditions like **heart failure**, **liver cirrhosis**, or **nephrotic syndrome** where there's an imbalance of hydrostatic and oncotic pressures. - The edema in this case is **non-pitting**, suggesting a higher protein content and tissue changes characteristic of lymphatic dysfunction, not systemic fluid overload leading to protein-poor fluid.

Question 3: A 47-year-old man presents as a new patient at an outpatient clinic. He has never seen a physician before, but was motivated by his 40-year-old brother's recent heart attack and seeks to optimize his health. In particular, he read that uncontrolled atherosclerosis can lead to a heart attack. Which molecule is downregulated in response to the advent of atherosclerosis?

A. Tumor necrosis factor
B. Serotonin
C. Nitric oxide (Correct Answer)
D. Interleukin 1
E. Thromboxane A2

Explanation: ***Nitric oxide*** - **Nitric oxide (NO)** is a potent **vasodilator** and **anti-inflammatory** molecule produced by endothelial cells. In atherosclerosis, endothelial dysfunction leads to reduced NO bioavailability. - Decreased NO production contributes to vasoconstriction, increased platelet aggregation, and enhanced smooth muscle cell proliferation, all of which promote **atherosclerotic plaque formation** and progression. *Tumor necrosis factor* - **Tumor necrosis factor-alpha (TNF-α)** is a **pro-inflammatory cytokine** that plays a significant role in the pathogenesis of atherosclerosis. - It is **upregulated** in response to atherosclerotic plaque formation, contributing to endothelial activation, leukocyte recruitment, and smooth muscle cell proliferation. *Serotonin* - **Serotonin (5-hydroxytryptamine)** is primarily known for its role as a neurotransmitter but also acts as a **vasoconstrictor** and promotes platelet aggregation. - While it can be released from activated platelets in the context of vascular injury, it is not consistently **downregulated** in atherosclerosis; rather, its effects can contribute to disease progression. *Interleukin 1* - **Interleukin-1 (IL-1)**, particularly IL-1β, is a major **pro-inflammatory cytokine** critically involved in the immune response in atherosclerosis. - It is **upregulated** in atherosclerotic plaques, contributing to systemic inflammation, endothelial dysfunction, and vascular smooth muscle cell activation. *Thromboxane A2* - **Thromboxane A2 (TXA2)** is a potent **vasoconstrictor** and **platelet aggregator** produced by activated platelets. - Its levels are **increased** in atherosclerosis, contributing to hypercoagulability and increased risk of thrombotic events like myocardial infarction.

Question 4: While playing in the woods with friends, a 14-year-old African-American male is bitten by an insect. Minutes later he notices swelling and redness at the site of the insect bite. Which substance has directly led to the wheal formation?

A. IFN-gamma
B. IL-4
C. IL-22
D. Histamine (Correct Answer)
E. Arachidonic acid

Explanation: ***Histamine*** - **Histamine** is a key mediator released by **mast cells** and basophils during immediate hypersensitivity reactions, such as an insect bite. - It causes vasodilation, increased vascular permeability, and itching, leading to the characteristic **wheal and flare** response. *IFN-gamma* - **IFN-gamma** is primarily involved in **Type IV hypersensitivity** (delayed-type) reactions and viral/intracellular bacterial defense. - It would not directly cause immediate wheal formation from an insect bite. *IL-4* - **IL-4** is crucial for **Th2 differentiation** and IgE production, which is involved in allergic reactions. - While essential for the underlying allergic response, it does not directly cause the acute wheal formation. *IL-22* - **IL-22** is involved in host defense, particularly against extracellular bacteria, and plays a role in tissue repair and inflammation, especially in epithelial tissues. - It is not a primary mediator of immediate hypersensitivity reactions or wheal formation. *Arachidonic acid* - **Arachidonic acid** is a precursor to eicosanoids (prostaglandins, leukotrienes), which mediate later phases of inflammation and pain. - While contributing to the overall inflammatory response, it does not directly cause the initial, rapid wheal formation.

Question 5: An 8-year-old boy is shifted to a post-surgical floor following neck surgery. The surgeon has restricted his oral intake for the next 24 hours. He does not have diarrhea, vomiting, or dehydration. His calculated fluid requirement is 1500 mL/day. However, he receives 2000 mL of intravenous isotonic fluids over 24 hours. Which of the following physiological parameters in the boy’s circulatory system is most likely to be increased?

A. Interstitial oncotic pressure
B. Interstitial hydrostatic pressure
C. Capillary wall permeability
D. Capillary oncotic pressure
E. Capillary hydrostatic pressure (Correct Answer)

Explanation: ***Capillary hydrostatic pressure*** - Giving 2000 mL of intravenous isotonic fluids when the calculated requirement is 1500 mL/day leads to a **positive fluid balance** and **fluid overload**. - This excess fluid directly increases the **intravascular volume**, thereby raising the **capillary hydrostatic pressure**, which pushes fluid out of the capillaries. *Interstitial oncotic pressure* - This pressure is primarily determined by the **protein concentration** in the interstitial fluid. - While fluid overload can dilute interstitial proteins, it generally does not directly increase interstitial oncotic pressure; rather, it might decrease it due to fluid movement. *Interstitial hydrostatic pressure* - As fluid moves out of the capillaries due to increased capillary hydrostatic pressure, the **interstitial hydrostatic pressure** will also increase. - However, the primary driving force for this change, and thus the most direct consequence of fluid overload, is the increase in capillary hydrostatic pressure. *Capillary wall permeability* - This parameter refers to the ease with which substances, including fluid and proteins, can cross the capillary wall. - Fluid overload does not typically affect **capillary wall permeability** unless there is an underlying condition causing inflammation or damage to the capillary endothelium. *Capillary oncotic pressure* - This pressure is mainly determined by the **protein concentration** within the capillaries. - In a state of fluid overload with isotonic fluids, the plasma proteins are diluted, leading to a **decrease** in capillary oncotic pressure, not an increase.

Question 6: A 48-year-old male dies in the intensive care unit following a severe Streptococcus pneumoniae pneumonia and septic shock. Autopsy of the lung reveals a red, firm left lower lobe. What would you most likely find on microscopic examination of the lung specimen?

A. Eosinophilia in the alveolar septa
B. Fragmented erythrocytes
C. Collagen whorls
D. Vascular dilation and noncaseating granulomas
E. Alveolar exudate containing neutrophils, erythrocytes, and fibrin (Correct Answer)

Explanation: ***Alveolar exudate containing neutrophils, erythrocytes, and fibrin*** - This describes the **red hepatization** stage of lobar pneumonia, which follows congestion and is characterized by a firm, red lung due to capillary congestion and extravasation of red blood cells, neutrophils, and fibrin into the alveoli. - The presence of **Streptococcus pneumoniae pneumonia** and the macroscopic finding of a **red, firm left lower lobe** are consistent with this stage of acute inflammation where inflammatory cells and plasma proteins fill the alveolar spaces. *Eosinophilia in the alveolar septa* - **Eosinophilia** in the lung is typically associated with allergic reactions, parasitic infections, or certain drug-induced lung diseases, not acute bacterial pneumonia. - The primary inflammatory cell in acute bacterial pneumonia, especially in the early stages, is the **neutrophil**. *Fragmented erythrocytes* - **Fragmented erythrocytes** (schistocytes) are typically seen in microangiopathic hemolytic anemias, such as thrombotic thrombocytopenic purpura or disseminated intravascular coagulation. - While septic shock can lead to DIC, fragmented erythrocytes are not the characteristic microscopic finding within the lung parenchyma itself for bacterial pneumonia. *Collagen whorls* - **Collagen whorls** are characteristic of conditions like silicosis, where they form within the lung parenchyma as part of a fibrotic response to inhaled silica particles. - This finding is indicative of chronic restrictive lung disease, not acute bacterial pneumonia. *Vascular dilation and noncaseating granulomas* - **Noncaseating granulomas** are the hallmark of diseases such as sarcoidosis, Crohn's disease, or foreign body reactions. - While vascular dilation can occur in inflammation, the presence of noncaseating granulomas would point away from an acute bacterial pneumonia and towards a granulomatous inflammatory process.

Question 7: A student is experimenting with the effects of nitric oxide in the body. He used a variety of amino acid isolates and measured the resulting nitric oxide levels and the physiological effects on the body. The amino acids function as substrates for nitric oxide synthase. After supplement administration, blood vessels dilated, and the systemic blood pressure decreased. Which of the following amino acids was used in this study?

A. Histidine
B. Tyrosine
C. Methionine
D. Arginine (Correct Answer)
E. Leucine

Explanation: ***Arginine*** - **Arginine** is the direct precursor to **nitric oxide (NO)** through the action of **nitric oxide synthase (NOS)**. - The production of NO leads to **vasodilation** and a subsequent decrease in **systemic blood pressure**, which aligns with the observed effects. *Histidine* - **Histidine** is a precursor for **histamine**, which can cause vasodilation, but it is not the direct substrate for **nitric oxide synthase**. - Its primary role in NO synthesis is indirect, unlike arginine. *Tyrosine* - **Tyrosine** is a precursor for **catecholamines** like dopamine, norepinephrine, and epinephrine, which are involved in various physiological responses but not directly in **nitric oxide synthesis**. - While catecholamines can affect blood pressure, their synthesis does not involve **nitric oxide synthase (NOS)** as a substrate. *Methionine* - **Methionine** is an essential amino acid primarily involved in **methylation reactions** and the synthesis of other sulfur-containing compounds. - It does not directly serve as a substrate for **nitric oxide synthase** in the production of nitric oxide. *Leucine* - **Leucine** is a branched-chain amino acid (BCAA) primarily involved in **protein synthesis** and muscle metabolism. - It does not serve as a substrate for **nitric oxide synthase** to produce nitric oxide.

Question 8: A 67-year-old woman is admitted to the hospital because of a 2-day history of fever, headache, jaw pain, and decreased vision in the right eye. Her erythrocyte sedimentation rate is 84 mm per hour. Treatment with methylprednisolone is initiated but her symptoms do not improve. The physician recommends the administration of a new drug. Three days after treatment with the new drug is started, visual acuity in the right eye increases. The beneficial effect of this drug is most likely due to inhibition of which of the following molecules?

A. Leukotriene D4
B. Interleukin-4
C. Complement component 5
D. Interleukin-6 (Correct Answer)
E. Thromboxane A2

Explanation: ***Interleukin-6*** - The patient's symptoms (fever, headache, jaw pain, decreased vision, elevated ESR) are classic for **giant cell arteritis (GCA)**. GCA involves transmural inflammation of medium to large arteries, often affecting the temporal artery and ophthalmic artery. - **Tocilizumab**, a monoclonal antibody that targets the **IL-6 receptor**, is an approved treatment for GCA, especially in cases unresponsive to corticosteroids or for steroid-sparing effects. Its efficacy in improving vision and reducing inflammation supports its action on IL-6. *Leukotriene D4* - **Leukotriene D4** is a potent bronchoconstrictor and mediator in allergic and asthmatic responses. - Inhibitors of leukotriene D4, such as montelukast, are used to treat **asthma** and **allergic rhinitis**, not vasculitis like GCA. *Interleukin-4* - **Interleukin-4** is a key cytokine in the **Th2 immune response**, promoting B-cell activation, **IgE production**, and allergic inflammation. - Drugs targeting IL-4 (or its receptor) are used in conditions like **atopic dermatitis** and **asthma**, not GCA, which is primarily a Th1-mediated inflammatory disease. *Complement component 5* - **Complement component 5 (C5)** is a central molecule in the **complement cascade**, playing a role in inflammation and cell lysis. - While the complement system can be involved in various inflammatory conditions, specific C5 inhibition is primarily seen with drugs like **Eculizumab** for paroxysmal nocturnal hemoglobinuria or atypical hemolytic uremic syndrome, which are distinct from GCA. *Thromboxane A2* - **Thromboxane A2** is a potent vasoconstrictor and platelet aggregator, primarily produced by platelets. - Its inhibition, typically by **aspirin**, is used for **antiplatelet effects** in cardiovascular disease and stroke prevention, not for the direct treatment of large vessel vasculitis or to rapidly resolve visual loss in GCA.

Question 9: A 4-year-old Caucasian boy is brought by his mother to the pediatrician with a red and swollen elbow. He was playing outside a few days prior to presentation when he fell and lightly scraped his elbow on the sidewalk. He was born at 34 weeks' gestation and was in the neonatal ICU for 2 days. His temperature is 102.1°F (38.9°C), blood pressure is 105/65 mmHg, pulse is 110/min, and respirations are 20/min. On exam, he has a swollen, erythematous, fluctuant, and exquisitely tender mass on his right elbow. There is expressible purulence coming from his wound. A peripheral blood smear in this patient would most likely reveal which of the following findings?

A. Absence of dark blue cytoplasmic staining upon nitroblue tetrazolium administration
B. Neutrophils with peroxidase-negative granules
C. Neutrophils with pale cytoplasm without granules
D. Neutrophils with abundant peroxidase-positive granules (Correct Answer)
E. Macrocytic erythrocytes and acanthocytes

Explanation: ***Neutrophils with abundant peroxidase-positive granules*** - This patient presents with a **typical acute bacterial skin and soft tissue infection** (abscess) following minor trauma. This is a **normal, age-appropriate scenario** in a healthy child. - In response to acute bacterial infection, the peripheral blood smear would show **normal, mature neutrophils with abundant peroxidase-positive (myeloperoxidase-positive) granules**. This is the **standard appearance of healthy, functioning neutrophils** responding to infection. - Additional findings might include **leukocytosis** with a **left shift** (increased band forms), but the neutrophils themselves would have normal morphology with prominent azurophilic (primary) and specific (secondary) granules that stain positive for peroxidase. - This is the expected finding in any patient with an acute bacterial infection and a normal immune system. *Absence of dark blue cytoplasmic staining upon nitroblue tetrazolium administration* - The **nitroblue tetrazolium (NBT) test** is a specialized diagnostic test for **Chronic Granulomatous Disease (CGD)**, where neutrophils cannot produce a respiratory burst due to defective NADPH oxidase. - However, this patient shows **no clinical evidence of CGD**: this is a **first-time infection** (not recurrent), occurring after **significant environmental exposure** (playing outside, scraping elbow on sidewalk), and the infection is responding as expected to inflammation. - Additionally, NBT testing is a **functional assay**, not a routine finding on peripheral blood smear examination. *Neutrophils with peroxidase-negative granules* - **Myeloperoxidase deficiency** is a rare neutrophil disorder where granules lack myeloperoxidase enzyme. - There is **no clinical indication** for this diagnosis in a child with a straightforward post-traumatic bacterial infection. - Most patients with myeloperoxidase deficiency are **asymptomatic** or have only mild infection susceptibility. *Neutrophils with pale cytoplasm without granules* - **Hypogranular or agranular neutrophils** are seen in **Chediak-Higashi syndrome** (which includes oculocutaneous albinism and neurologic abnormalities) or **myelodysplastic syndromes**. - This patient has an **acute infection with normal inflammatory response**, making these conditions extremely unlikely. - Chediak-Higashi syndrome would present with additional features like partial albinism and easy bruising. *Macrocytic erythrocytes and acanthocytes* - **Macrocytic erythrocytes** suggest vitamin B12/folate deficiency, liver disease, or hypothyroidism. - **Acanthocytes** (spur cells) are associated with severe liver disease, abetalipoproteinemia, or neuroacanthocytosis. - These red blood cell abnormalities are **completely unrelated** to this patient's presentation of acute bacterial skin infection.

Question 10: A 32-year-old man who recently emigrated from Somalia comes to the physician because of a 4-week history of fever, cough, and chest pain. He has had a 5-kg (11-lb) weight loss over the last 3 months despite no changes in appetite. His temperature is 38.1°C (100.6°F). Physical examination shows enlarged cervical lymph nodes. The lungs are clear to auscultation. The results of an interferon-γ release assay are positive. An x-ray of the chest shows bilateral mediastinal lymphadenopathy. A transbronchial needle aspiration biopsy of a mediastinal lymph node is performed; a photomicrograph of the specimen is shown. The structure indicated by the arrow is most likely comprised of which of the following types of cells?

A. Natural killer cells
B. B cells
C. Fibroblasts
D. Neutrophils
E. Macrophages (Correct Answer)

Explanation: ***Macrophages*** - The photomicrograph shows a **granuloma**, characterized by collections of **epithelioid histiocytes** (modified macrophages) and **multinucleated giant cells**, which are essentially fused macrophages. - This morphology, coupled with the clinical picture of fever, cough, weight loss, positive interferon-γ release assay, and mediastinal lymphadenopathy in a patient from an endemic area, is highly suggestive of **tuberculosis**, a classic granulomatous disease. *Natural killer cells* - Natural killer cells are part of the innate immune system and are primarily involved in **killing virally infected cells** and **tumor cells**. - They are not the primary cellular component forming the characteristic structure of a granuloma. *B cells* - B cells are responsible for **antibody production** and antigen presentation. - While B cells may be present in the periphery of a granuloma, they do not form the core epithelioid and giant cell components. *Fibroblasts* - Fibroblasts produce **collagen** and the extracellular matrix, playing a role in **scar formation** and the fibrotic wall that can surround chronic granulomas. - They do not constitute the primary cellular components of the inflammatory core of a granuloma. *Neutrophils* - Neutrophils are typically associated with **acute inflammation** and bacterial infections, characterized by pus formation. - They are not the predominant cell type in the organized structure of a **granuloma** found in tuberculosis.

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