Inflammation and Repair Practice Questions

Q: All of the following are Integrin molecules except?

CD 31. **Explanation:** The question tests the classification of **Cell Adhesion Molecules (CAMs)**, which are critical for leukocyte migration and the inflammatory response. **Why CD 31 is the correct answer:** **CD 31**, also known as **PECAM-1** (Platelet Endothelial Cell Adhesion Molecule-1), belongs to the **Immunoglobulin (Ig) Superfamily**, not the Integrin family. Its primary role is in **diapedesis** (transendothelial migration), where it helps leukocytes squeeze through endothelial cell junctions. **Analysis of Incorrect Options (Integrin Family):** Integrins are heterodimeric surface proteins (alpha and beta chains) that mediate firm adhesion of leukocytes to the endothelium. * **LFA-1 (Lymphocyte Function-associated Antigen-1):** Also known as **CD11a/CD18**. It is a $\beta_2$-integrin that binds to ICAM-1. * **MAC-1 (Macrophage-1 antigen):** Also known as **CD11b/CD18**. It is a $\beta_2$-integrin that binds to ICAM-1 and acts as a receptor for iC3b. * **VLA-4 (Very Late Antigen-4):** Also known as **$\alpha_4\beta_1$ integrin**. It binds to VCAM-1 on endothelial cells. **High-Yield Clinical Pearls for NEET-PG:** 1. **Leukocyte Adhesion Deficiency (LAD) Type 1:** Caused by a deficiency in the **$\beta_2$ chain (CD18)** of integrins (LFA-1/MAC-1). Clinical features include delayed separation of the umbilical cord, recurrent bacterial infections without pus formation, and extreme neutrophilia. 2. **Sequence of Leukocyte Migration:** * **Rolling:** Mediated by **Selectins** (E, P, and L-selectin). * **Firm Adhesion:** Mediated by **Integrins** (LFA-1, VLA-4) binding to Ig-Superfamily ligands (ICAM-1, VCAM-1). * **Diapedesis:** Mediated by **PECAM-1 (CD 31)**. 3. **Sialyl-Lewis X:** The carbohydrate ligand on leukocytes that binds to P and E-selectins; its deficiency causes **LAD Type 2**.

Q: Which defect is identified by the nitroblue tetrazolium test?

Phagocytosis. The **Nitroblue Tetrazolium (NBT) test** is a classic diagnostic tool used to assess the **oxidative burst** capacity of phagocytes (neutrophils and macrophages). Phagocytosis involves the ingestion of pathogens, followed by their destruction via reactive oxygen species (ROS) [1]. This process is mediated by the **NADPH oxidase enzyme complex**. In a normal cell, NADPH oxidase reduces the yellow NBT dye into insoluble, dark blue **formazan crystals**. A positive NBT test (blue color) indicates intact phagocytic killing power. A negative NBT test (no color change) indicates a defect in the oxidative burst, most characteristically seen in **Chronic Granulomatous Disease (CGD)**. Complement defects are typically screened using the **CH50 assay** (for classical pathway) or **AH50** (for alternative pathway). T-cell function is evaluated via delayed-type hypersensitivity (DTH) skin tests, flow cytometry (CD3/CD4/CD8 counts), or mitogen stimulation assays. B-cell function is assessed by measuring serum immunoglobulin levels (IgG, IgA, IgM) or quantifying CD19/CD20+ cells via flow cytometry. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 89-92.

Q: Teuton giant cells are seen in which of the following conditions?

Xanthoma. **Explanation:** **Touton giant cells** (also known as xanthelasmic giant cells) are the hallmark histological feature of **Xanthomas**. These are specialized multinucleated giant cells formed by the fusion of macrophages (histiocytes). **Why Xanthoma is correct:** The underlying mechanism involves the accumulation of lipids [1]. In Touton giant cells, nuclei form a complete or partial ring around a central area of homogeneous eosinophilic cytoplasm. Crucially, the **peripheral cytoplasm** outside the ring of nuclei appears **foamy or vacuolated** due to the presence of processed lipids (cholesterol) [1]. This characteristic "wreath-like" arrangement is diagnostic of lesions with high lipid content, such as xanthomas, xanthogranulomas, and fat necrosis. **Why other options are incorrect:** * **Sarcoidosis:** Characterized by non-caseating granulomas containing **Langhans giant cells** and specific inclusions like **Asteroid bodies** and **Schaumann bodies**. * **Tuberculosis:** Features caseating granulomas with **Langhans giant cells**, where nuclei are arranged in a peripheral "horseshoe" pattern. * **Foreign body granuloma:** Contains **Foreign body giant cells**, where nuclei are disorganized and scattered randomly throughout the cytoplasm. **High-Yield Clinical Pearls for NEET-PG:** * **Touton Giant Cell:** Central eosinophilic cytoplasm + Ring of nuclei + Peripheral foamy cytoplasm. * **Langhans Giant Cell:** Peripheral horseshoe nuclei (seen in TB, Sarcoidosis). * **Foreign Body Giant Cell:** Haphazard/scattered nuclei. * **Aschoff Cells:** Found in Rheumatic Heart Disease (Anitschkow cells are the mononuclear precursors). * **Warthin-Finkeldey Cells:** Multinucleated giant cells seen in Measles. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 73-74.

Question 1

All of the following are Integrin molecules except?

Accepted Answer

CD 31

Answer

LFA-1

Answer

MAC-1

Answer

VLA-4

Question 2

A 24-year-old female presents with severe pain during menses (dysmenorrhea). To treat her symptoms, you advise her to take indomethacin in the hopes that it will reduce her pain by interfering with the production of which substance?

Accepted Answer

Prostaglandin F2

Answer

Bradykinin

Answer

Histamine

Answer

Phospholipase A2

Question 3

Which defect is identified by the nitroblue tetrazolium test?

Accepted Answer

Phagocytosis

Answer

Complement

Answer

T cell

Answer

B cell

Question 4

Increased capillary permeability is caused by all of the following except?

Accepted Answer

Renin

Answer

Anaphylatoxin

Answer

5-hydroxytryptamine

Answer

Histamine

Question 5

Bronchospasm is initiated by?

Accepted Answer

Leukotrienes

Answer

C5a

Answer

C3a

Answer

Acetylcholines

Question 6

All of the following are pyrogenic cytokines, except?

Accepted Answer

Interleukin 18 (IL-18)

Answer

Interleukin 6 (IL-6)

Answer

Tumor Necrosis Factor (TNF)

Answer

Interferon alpha (IFN-a)

Question 7

Teuton giant cells are seen in which of the following conditions?

Accepted Answer

Xanthoma

Answer

Sarcoidosis

Answer

Tuberculosis

Answer

Foreign body granuloma

Question 8

Non-caseating granuloma is characteristically seen in:

Accepted Answer

Sarcoidosis

Answer

Syphilis

Answer

Tuberculosis

Answer

Cat-scratch disease

Question 9

All of the following are characteristic of exudates EXCEPT:

Accepted Answer

Protein content less than 1 gm/dL

Answer

Predominantly polymorphonuclear cells

Answer

Specific gravity greater than 1.015

Answer

Turbid appearance of the fluid

Question 10

Which of the following is an endogenous chemoattractant?

Accepted Answer

C5a

Answer

Bacterial products

Answer

Lipopolysaccharide A

Answer

C8

Inflammation and Repair — MCQs

Inflammation and Repair — MCQs

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