Inflammation and Repair Practice Questions

Q: Which leukotriene acts as an adhesion factor for neutrophils to attach to the endothelium on the cell surface?

Leukotriene B4. **Explanation:** **Leukotriene B4 (LTB4)** is a potent inflammatory mediator derived from the lipoxygenase pathway of arachidonic acid metabolism. It plays a critical role in the recruitment of leukocytes to the site of inflammation. Specifically, LTB4 acts as a powerful **chemotactic agent** and an **activator of neutrophil adhesion** [1]. It induces the expression of integrins (high-affinity state) on the surface of neutrophils, allowing them to firmly attach to the vascular endothelium before undergoing transmigration (diapedesis) [1]. **Analysis of Incorrect Options:** * **Leukotriene C4, D4, and E4:** These are collectively known as **cysteinyl leukotrienes** (or the "slow-reacting substance of anaphylaxis"). Their primary physiological roles include: * **Vasoconstriction** (unlike LTB4). * **Increased vascular permeability** (via contraction of endothelial cells in post-capillary venules). * **Bronchospasm** (significant in the pathogenesis of asthma). They do not possess the chemotactic or pro-adhesive properties characteristic of LTB4. **NEET-PG High-Yield Pearls:** * **The "Big Four" Chemotactic Agents:** Remember the mnemonic **"C-I-L-B"** for the most important chemotactic factors for neutrophils: **C**5a, **I**L-8, **L**TB4, and **B**acterial products (N-formyl methionine) [1]. * **Lipoxins:** While leukotrienes are pro-inflammatory, Lipoxins (LXA4, LXB4) are anti-inflammatory and inhibit neutrophil recruitment. * **Pharmacology Link:** Zileuton inhibits 5-lipoxygenase (preventing all LT synthesis), while Montelukast/Zafirlukast are LTD4 receptor antagonists used in asthma. **References:** [1] 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.

Q: Which of the following is NOT a granulomatous disease?

Pneumocystis jirovecii pneumonia. **Explanation:** A **granuloma** is a focal collection of inflammatory cells, primarily activated macrophages (epithelioid cells), often surrounded by a rim of lymphocytes and sometimes containing multinucleated giant cells. It is a manifestation of **Type IV hypersensitivity** in response to persistent irritants. **Why D is the Correct Answer:** * **Pneumocystis jirovecii pneumonia (PJP):** This is an opportunistic fungal infection typically seen in immunocompromised patients (e.g., HIV/AIDS). Pathologically, it is characterized by an **intra-alveolar foamy, "cotton-candy" exudate** containing the organisms. It does not typically elicit a granulomatous response because the host's cell-mediated immunity is usually too suppressed to form granulomas. **Why the other options are Incorrect:** * **A. Syphilis:** Characterized by the **Gumma**, a type of granuloma with central necrosis (coagulative) surrounded by mononuclear cells and plasma cells. * **B. Sarcoidosis:** The classic example of **non-caseating granulomas**. These contain asteroid bodies and Schaumann bodies within giant cells. * **C. Schistosomiasis:** A parasitic infection where the host forms **eosinophilic granulomas** around the trapped eggs in the liver or bladder wall. **NEET-PG High-Yield Pearls:** * **Caseating Granuloma:** Tuberculosis (central "cheesy" necrosis). * **Non-Caseating Granuloma:** Sarcoidosis, Crohn’s disease, Leprosy (Tuberculoid), and Berylliosis. * **Stellate Granuloma:** Cat-scratch disease and Lymphogranuloma venereum (LGV). * **Suppurative Granuloma:** Fungal infections and Melioidosis. * **PJP Diagnosis:** Best visualized using **Gomori Methenamine Silver (GMS)** stain, showing crushed "ping-pong ball" shaped cysts.

Q: Which of the following is NOT a mononuclear-macrophage?

B-cells. ### Explanation The **Mononuclear Phagocyte System (MPS)**, formerly known as the Reticuloendothelial System, consists of phagocytic cells derived from bone marrow hematopoietic stem cells (monoblasts). These cells circulate in the blood as **monocytes** and eventually migrate into various tissues to mature into specialized **macrophages**. **Why B-cells are the correct answer:** B-cells are **lymphocytes**, not part of the mononuclear-macrophage lineage. While B-cells can function as Professional Antigen-Presenting Cells (APCs), they are primarily responsible for humoral immunity (antibody production) and do not possess the phagocytic morphology or lineage markers of the MPS. **Analysis of incorrect options:** * **Histiocytes:** These are the resident macrophages found in **connective tissue**. * **Microglia:** These are the specialized macrophages of the **Central Nervous System (CNS)**. They are unique as they are the only immune cells resident in the brain parenchyma. * **Kupffer cells:** These are specialized macrophages located in the **liver sinusoids**, responsible for clearing pathogens and aged erythrocytes from the portal circulation. **High-Yield Clinical Pearls for NEET-PG:** * **Other Tissue Macrophages:** * **Alveolar Macrophages:** Dust cells (Lungs) * **Osteoclasts:** Bone * **Mesangial cells:** Kidney * **Langerhans cells:** Skin (Note: These are dendritic cells, but often grouped in older MPS classifications). * **Littoral cells:** Spleen * **Key Marker:** **CD14** is a specific surface marker for monocytes and macrophages. * **Function:** Macrophages are essential for innate immunity, chronic inflammation, and secreting cytokines like IL-1, IL-6, and TNF-α.

Question 1

C3a and C5a are called?

Accepted Answer

Anaphylotoxins

Answer

Chemotactic agent

Answer

Lytic complex

Answer

Opsonins

Question 2

Which is the most important adhesion molecule for diapedesis?

Accepted Answer

CD31

Answer

CD34

Answer

P-selectin

Answer

E-selectin

Question 3

In wound healing, what is the correct sequence of cell appearance?

Accepted Answer

Platelet -> Neutrophils -> Macrophages -> Fibroblast

Answer

Macrophage -> Platelet -> Neutrophils -> Fibroblast

Answer

Neutrophils -> Macrophages -> Platelet -> Fibroblast

Answer

Platelet -> Macrophages -> Neutrophils -> Fibroblast

Question 4

Which leukotriene acts as an adhesion factor for neutrophils to attach to the endothelium on the cell surface?

Accepted Answer

Leukotriene B4

Answer

Leukotriene C4

Answer

Leukotriene D4

Answer

Leukotriene E4

Question 5

Which of the following is NOT a granulomatous disease?

Accepted Answer

Pneumocystis jirovecii pneumonia

Answer

Syphilis

Answer

Sarcoidosis

Answer

Schistosomiasis

Question 6

In which condition are plasma cells increased?

Accepted Answer

Rheumatoid arthritis

Answer

Acute appendicitis

Answer

Bronchitis

Answer

Bristles of burnt skin

Question 7

Neutrophil hypomotility syndrome is due to?

Accepted Answer

Defective actin polymerization

Answer

Deficiency of leukocyte integrins

Answer

Defect in free radical production

Answer

Absence of actin

Question 8

Which of the following is NOT a mononuclear-macrophage?

Accepted Answer

B-cells

Answer

Histiocytes

Answer

Microglia

Answer

Kupffer cells

Question 9

Formation of excessive amounts of granulation tissue, which protrudes above the level of the surrounding skin and blocks re-epithelialization, is called?

Accepted Answer

Proud flesh

Answer

Keloid

Answer

Desmoid

Answer

Hypertrophic scar

Question 10

A 34-year-old man presents with a 5-day history of a painful sore on his hand. Physical examination reveals a 0.5-cm abscess on the extensor surface of the left hand that drains a thick, purulent material. Diapedesis of leukocytes into and around this patient's infected wound occurs primarily at which of the following anatomic locations?

Accepted Answer

Postcapillary venules

Answer

Lymphatic capillaries

Answer

Precapillary aerioles

Answer

Small dermal arteries

Inflammation and Repair — MCQs

Inflammation and Repair — MCQs

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