Inflammation and Repair Practice Questions

Q: Which of the following cytokines stimulate acute phase reactants?

All of the options. ***All of the above*** - Acute phase reactants are stimulated by various **cytokines**, including IL-6, TNF-α, and IL-1, highlighting a coordinated immune response [1]. - The presence of multiple cytokines indicates that a range of **inflammatory processes** contributes to the activation of the acute phase response [1]. *IL-6* - While IL-6 is indeed a **key mediator** in acute phase reactions, it is not the only cytokine responsible for stimulating this response [1]. - Other cytokines like **TNF-α** and **IL-1** also play significant roles, making this option incomplete [1][2]. *TNF-a* - TNF-α is a crucial cytokine that can stimulate acute phase reactants, but it does not act alone in this process [2]. - The role of **multiple cytokines** (including IL-6 and IL-1) makes this option insufficient on its own [1]. *IL-1* - IL-1 is known to activate acute phase reactants, but similar to the others, it is **not the sole factor** and works in conjunction with other cytokines [2]. - Therefore, like TNF-α and IL-6, its contribution alone does not capture the complete picture [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 97-99. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 110-111.

Q: What is responsible for regeneration of liver cells?

HGF. **HGF** - **Hepatocyte growth factor (HGF)** is the primary growth factor responsible for stimulating hepatocyte proliferation and migration, playing a crucial role in **liver regeneration** after injury or resection. - It acts as a potent **mitogen** for hepatocytes, promoting their entry into the cell cycle and division. *VEGF* - **Vascular endothelial growth factor (VEGF)** is primarily involved in **angiogenesis**, the formation of new blood vessels. - While important for tissue repair, it does not directly stimulate the proliferation of liver cells themselves. *TGF-beta* - **Transforming growth factor-beta (TGF-β)** is generally considered an **inhibitor of cell proliferation** and a promoter of fibrosis in the liver. - It can suppress hepatocyte growth and promote the differentiation of stellate cells into myofibroblasts, leading to **scar formation**. *IFN-γ* - **Interferon-gamma (IFN-γ)** is a cytokine primarily involved in **immune responses** and has anti-proliferative and pro-apoptotic effects on various cell types. - It does not promote liver cell regeneration; instead, it can be involved in liver injury and fibrosis during chronic inflammation.

Q: What is the primary mediator of vasodilatation following endothelial damage?

Histamine. ***Histamine*** - Histamine is a ** potent vasodilator** released during endothelial damage, leading to increased vascular permeability and blood flow [1]. - It causes **smooth muscle relaxation** in the blood vessels, contributing to vasodilatation [1]. - Histamine is one of the most important mediators of acute inflammation, normally sequestered in intracellular granules and rapidly secreted by granule exocytosis from mast cells [2]. *TGF-3* - Transforming growth factor-beta 3 (TGF-3) primarily plays a role in **cell differentiation and inflammation**, rather than immediate vasodilatation. - It is not directly involved in the acute vascular response to endothelial injury. *IL-2* - Interleukin-2 (IL-2) is mainly associated with **T-cell proliferation** and activation in the immune response, not with vasodilatation. - Its effects are more related to **adaptive immunity** rather than direct vascular effects. *FGF* - Fibroblast growth factor (FGF) is involved in **angiogenesis** and tissue repair but does not induce immediate vasodilatation post-endothelial damage. - It primarily promotes **cell proliferation** and differentiation rather than causing direct vasodilatation. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 84-85. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 93-94.

Q: Normal time for wound healing to transition from proliferative to maturation phase after injury is?

3 weeks. ***4 weeks*** - The normal time for scar formation is generally around **4 weeks**, allowing for significant collagen deposition and remodeling [1]. - This timeframe signifies the transition from initial wound healing to the maturation phase where the scar solidifies. *2 weeks* - At 2 weeks, the healing is in the **inflammatory** and early proliferative phase, not fully developed into a scar. - Scar formation generally requires a longer duration for sufficient **collagen synthesis** and tissue remodeling. *3 weeks* - By 3 weeks, the wound is progressing, but it still lacks the **structural integrity** of a mature scar. - Scar formation typically reaches its recognizable stage by **4 weeks**, with formal remodeling continuing thereafter. *5 weeks* - While healing continues past 4 weeks, **5 weeks** is longer than the typical duration for initial scar formation, possibly suggesting delayed healing. - By this point, the scar should be present, but significant remodeling will still occur beyond this period. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 117-119.

Q: Leukocyte adhesion to endothelium is mediated by all except?

VCAM-4. ***VCAM 4*** - **VCAM-4** is not a recognized mediator for leukocyte adhesion; instead, **VCAM-1** plays a significant role in this process. - Adhesion is primarily mediated by interactions between leukocyte integrins and endothelial **selectins** and **VCAM-1** [1]. *E selectin* - **E selectin** is involved in the adhesion of leukocytes to endothelium, particularly during inflammation [1]. - It helps in the adhesion process during the **rolling** phase of leukocyte extravasation [2]. *L selectin* - **L selectin** is crucial for the initial adhesion of leukocytes to the **high endothelial venules** in lymphoid tissues [1]. - It facilitates leukocyte **homing** to lymphoid organs, aiding in a variety of immune responses. *VCAM 1* - **VCAM-1** is a key adhesion molecule that facilitates the binding of leukocytes to endothelial cells, particularly in inflammation [3]. - Interacts with the integrin **VLA-4** on leukocytes, promoting firm adhesion during the immune response. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, p. 87. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Migration in the tissues toward a chemotactic stimulus, pp. 86-87. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 87-89.

Q: All of the following statements are true regarding neutrophil extracellular trapping (NET) except for which of the following?

Mitochondrial DNA is seen. ***Mitochondrial DNA is seen*** - NETs (Neutrophil Extracellular Traps) are made primarily of **nuclear chromatin**, not mitochondrial DNA [2]. - The main purpose of NETs is to trap and kill pathogens, focusing on **nuclear genetic material** rather than mitochondrial components. *It is detected in blood during sepsis* - NETs can indeed be found in the **circulation during sepsis**, serving as a defense mechanism against infections. - Their presence in blood indicates an **active immune response**, particularly in severe systemic infections. *It is produced in response to bacterial infection* - NET formation is a known response to **bacterial infections**, as neutrophils deploy them to capture and neutralize pathogens. - This process helps in controlling infections, showcasing the importance of NETs in **innate immunity**. *It is chromatin with antibacterial enzymes* - NETs consist primarily of **decondensed chromatin**, embedded with **antimicrobial proteins** and enzymes to combat pathogens [1][2]. - This characteristic underscores their role in targeting and eliminating invading microorganisms effectively. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 91-92. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 92-93.

Q: What is the main feature of chemotaxis as observed in white blood cells?

Unidirectional locomotion of neutrophils. ***Unidirectional locomotion of neutrophils*** - **Chemotaxis** refers to the **directional movement** of cells, such as neutrophils, towards a chemical attractant. - This process is crucial for recruiting immune cells to sites of infection or inflammation. *Increased random movement of neutrophils* - While neutrophils do exhibit random movement, **chemotaxis** specifically describes **directed movement** along a chemical gradient, not merely an increase in random motion. - **Random movement** without a specific direction does not effectively guide immune cells to a specific target. *Increased adhesiveness to intima* - **Adhesion to the intima** (endothelial cells) is an initial step in the process of leukocyte extravasation, allowing cells to roll and stick to vessel walls. - However, it is primarily mediated by adhesion molecules and is distinct from the **directional migration** defined by chemotaxis. *Increased phagocytosis* - **Phagocytosis** is the process by which cells engulf pathogens or cellular debris. - While essential for immune function, it is a separate function that occurs **after** the cell has migrated to its target via chemotaxis.

Q: A 33-year-old man presents with a 5-week history of calf pain, swelling, and low-grade fever. Serum levels of creatinine kinase are elevated. A muscle biopsy reveals numerous eosinophils and he also has peripheral blood eosinophilia. Which of the following interleukins is primarily responsible for the increase in eosinophils in this patient?

IL-5. ***IL-5*** - **Interleukin-5 (IL-5)** is the **most potent and direct cytokine** responsible for the **differentiation, maturation, activation, and survival of eosinophils**. - IL-5 is produced primarily by **Th2 cells**, mast cells, and eosinophils themselves, and acts directly on eosinophil progenitors in the bone marrow. - In this patient with eosinophilic myositis (likely parasitic infection such as trichinosis), **IL-5 is the primary mediator** of the peripheral blood eosinophilia and tissue eosinophil infiltration. - **Clinical correlation:** Anti-IL-5 therapies (mepolizumab, reslizumab) are used to treat hypereosinophilic conditions, confirming IL-5's central role. *IL-4* - **Interleukin-4 (IL-4)** is produced by Th2 cells and mast cells and promotes the **differentiation of naive T cells into Th2 cells**. - While IL-4 initiates the Th2 immune response that eventually leads to IL-5 production, it does **not directly stimulate eosinophil production or recruitment**. - IL-4 is more involved in IgE class switching and allergic inflammation rather than direct eosinophil regulation. *IL-6* - **Interleukin-6 (IL-6)** is a pleiotropic cytokine involved in the **acute phase response**, inflammation, and hematopoiesis. - While it has broad effects on immune cells, it is **not primarily responsible** for eosinophil production or recruitment. - Elevated in many inflammatory conditions but not specific for eosinophilia. *IL-2* - **Interleukin-2 (IL-2)** is primarily involved in the **proliferation and differentiation of T lymphocytes** and activation of natural killer (NK) cells. - It plays no significant direct role in eosinophil production or recruitment. - More important for T cell-mediated immunity rather than eosinophilic responses.

Q: What is one of the primary functions of Interleukin-1 (IL-1)?

Acts as an endogenous pyrogen. ***Acts as an endogenous pyrogen*** - **Interleukin-1 (IL-1)** is a key **pro-inflammatory cytokine** that plays a central role in the body's response to infection and injury. - One of its primary functions is to act as an **endogenous pyrogen**, meaning it can induce **fever** by promoting prostaglandin synthesis in the hypothalamus, thereby raising the body's set point temperature. *Inhibits T cell proliferation* - IL-1 generally **enhances T cell activation and proliferation**, particularly in conjunction with other signals, rather than inhibiting it. - **Immunosuppressive cytokines** like **TGF-β** or **IL-10** are known to inhibit T cell proliferation. *Suppresses antibody production* - IL-1 is generally involved in **promoting B cell activation** and **antibody production**, either directly or indirectly through its effects on T helper cells. - Cytokines like **IL-10** can sometimes suppress certain aspects of antibody production but IL-1 is not known for this role. *Reduces inflammatory cell recruitment* - IL-1 is a potent **pro-inflammatory cytokine** that actively **promotes the recruitment** of immune cells, such as neutrophils and monocytes, to sites of inflammation. - It does this by inducing the expression of **adhesion molecules** and **chemokines** on endothelial cells.

Question 1

Which of the following cytokines stimulate acute phase reactants?

Accepted Answer

All of the options

Answer

IL-1

Answer

IL-6

Answer

TNF-α

Question 2

What is responsible for regeneration of liver cells?

Accepted Answer

HGF

Answer

TGF-beta

Answer

VEGF

Answer

IFN-γ

Question 3

What is the primary mediator of vasodilatation following endothelial damage?

Accepted Answer

Histamine

Answer

IL-2

Answer

TGF-β3

Answer

FGF

Question 4

Normal time for wound healing to transition from proliferative to maturation phase after injury is?

Accepted Answer

3 weeks

Answer

2 weeks

Answer

4 weeks

Answer

5 weeks

Question 5

Leukocyte adhesion to endothelium is mediated by all except?

Accepted Answer

VCAM-4

Answer

L-selectin

Answer

VCAM-1

Answer

E-selectin

Question 6

What is the definition of exudate?

Accepted Answer

Extravascular fluid that has a high protein concentration and contains cellular debris

Answer

Extravascular fluid that has a low protein concentration

Answer

Extravascular fluid with high glucose concentration

Answer

Extravascular fluid with low glucose concentration

Question 7

All of the following statements are true regarding neutrophil extracellular trapping (NET) except for which of the following?

Accepted Answer

Mitochondrial DNA is seen

Answer

It is detected in blood during sepsis

Answer

It is chromatin with antibacterial enzymes

Answer

It is produced in response to bacterial infection

Question 8

What is the main feature of chemotaxis as observed in white blood cells?

Accepted Answer

Unidirectional locomotion of neutrophils

Answer

Increased random movement of neutrophils

Answer

Increased adhesiveness to intima

Answer

Increased phagocytosis

Question 9

A 33-year-old man presents with a 5-week history of calf pain, swelling, and low-grade fever. Serum levels of creatinine kinase are elevated. A muscle biopsy reveals numerous eosinophils and he also has peripheral blood eosinophilia. Which of the following interleukins is primarily responsible for the increase in eosinophils in this patient?

Accepted Answer

IL-5

Answer

IL-4

Answer

IL-6

Answer

IL-2

Question 10

What is one of the primary functions of Interleukin-1 (IL-1)?

Accepted Answer

Acts as an endogenous pyrogen

Answer

Reduces inflammatory cell recruitment

Answer

Inhibits T cell proliferation

Answer

Suppresses antibody production

Inflammation and Repair — MCQs

Inflammation and Repair — MCQs

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