NEET-PG 2015 - Pathology Practice Questions

Q: Chemotaxis is mediated by-

Leukotriene B4 and C5a. ***Leukotriene B4 and C5a*** - Both **Leukotriene B4** [2] and **C5a** [1] are potent **chemoattractants** that guide the migration of neutrophils and other immune cells to sites of inflammation. - They are crucial in amplifying the **immune response**, particularly during acute inflammatory reactions. *Histamine* - Primarily involved in **vasodilation** and increased **vascular permeability**, rather than mediating chemotaxis. - Does not specifically attract immune cells to sites of injury or infection like leukotrienes do. *Bradykinin* - Mainly functions in **pain sensation** and promoting **vascular permeability**, not as a direct chemotactic agent. - It influences inflammation but does not effectively recruit immune cells to tissues. *Leukotriene C4 and C3a* - **Leukotriene C4** is involved in bronchoconstriction, while **C3a** [1] has roles in the complement system but is less potent than C5a in chemotaxis. - These mediators have different primary roles in inflammation, lacking the specificity of B4 and C5a for leukocyte attraction. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 99-100. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 95-96.

Q: Interleukin responsible for Pyrexia is:

IL1. ***IL1*** - **Interleukin-1 (IL-1)** is a primary **endogenous pyrogen**, directly acting on the thermoregulatory center in the hypothalamus to induce fever. - It stimulates the production of **prostaglandin E2 (PGE2)**, which then alters the hypothalamic set point, leading to increased body temperature. *IL3* - **Interleukin-3 (IL-3)** is a **hematopoietic growth factor** that primarily stimulates the proliferation and differentiation of hematopoietic stem cells. - Its main role is in the development of various blood cell lineages, not directly in inducing fever. *IL4* - **Interleukin-4 (IL-4)** is a key cytokine in **allergic reactions** and **Th2 immune responses**, promoting B cell activation and IgE production. - It does not directly cause pyrexia; its primary functions are related to humoral immunity and immune regulation. *IL8* - **Interleukin-8 (IL-8)**, also known as **CXCL8**, is a potent **chemotactic factor** for neutrophils and other immune cells. - Its main function is to recruit inflammatory cells to sites of infection or injury, not to induce fever directly.

Q: Post-streptococcal glomerulonephritis (PSGN) is an example of which type of hypersensitivity?

Type -3 hypersensitivity. ***Type -3 hypersensitivity*** - Post-streptococcal glomerulonephritis (PSGN) is caused by **immune complex deposition**, a hallmark of type III hypersensitivity reactions [1][2][3]. - It involves the formation of **antigen-antibody complexes** following a streptococcal infection, leading to inflammation in the kidneys [1][2]. *Type -1 hypersensitivity* - Characterized by **IgE-mediated** reactions, such as allergies and anaphylaxis, which do not apply to PSGN. - It typically involves **mast cells** and histamine release, notably absent in PSGN cases. *Type -4 hypersensitivity* - Involves **T-cell mediated** responses and is related to delayed-type reactions, not applicable to PSGN. - Common examples include **contact dermatitis** and graft-versus-host disease, differing fundamentally from PSGN's mechanism. *Type -2 hypersensitivity* - Characterized by **antibody-mediated cytotoxicity**, such as in hemolytic anemia, unrelated to immune complexes in PSGN. - Typically involves direct damage to cells, contrasting with the immune complex mechanism observed in PSGN [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 214-215. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 910-915. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 215-216.

Q: What is the number of antigens typically evaluated in comprehensive HLA matching for organ transplantation?

10. ***10*** - The **number of criteria for HLA matching** in organ transplantation is typically 10, consisting of 6 class I and 4 class II antigens. - Proper HLA matching is critical for minimizing the risk of **graft rejection** and ensuring **recipient compatibility** [1]. *16* - While there are various HLA antigens, a total of **16** criteria is not a standard number used for matching purposes. - This number may include other factors but does not represent the core criteria for **HLA matching**. *4* - HLA matching involves more than **4 criteria**, inadequate for reliable transplantation outcomes. - This number does not encompass the essential **class I and class II antigens** that are necessary for effective matching. *22* - A total of **22 criteria** exceeds the conventional standard for HLA matching, which is not practical or necessary. - This figure may relate to overall HLA typing but is not applicable for the matching process itself. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 179-180.

Q: What is the most common type of graft rejection?

Acute. ***Acute*** - **Acute rejection** is the most common type of graft rejection, occurring in **10-40% of transplant recipients**. [1] - It typically occurs **days to weeks to months** after transplantation (most commonly within the first 6 months). [1] - Mediated primarily by **T-lymphocytes** (cellular rejection) or **antibodies** (antibody-mediated rejection) reacting against donor antigens. [1] - Usually **responsive to immunosuppressive therapy** when detected early. *Hyperacute* - **Hyperacute rejection** is rare (occurs in <1% of cases) due to routine **pre-transplant cross-matching**. - Occurs within **minutes to hours** after transplantation due to **pre-existing circulating antibodies** against donor antigens. [1] - Results in immediate thrombosis and graft necrosis, requiring **immediate graft removal**. [1] *Chronic* - **Chronic rejection** (chronic allograft dysfunction) develops **months to years** after transplantation. - It is the **most common cause of late graft failure**, but not the most common type of rejection episode. - Characterized by **gradual, progressive loss of graft function** with vascular and fibrotic changes. - **Largely irreversible** and poorly responsive to treatment. *Acute on chronic* - This is **not a primary category** of graft rejection but represents an **acute rejection episode superimposed** on a graft already undergoing chronic changes. - Reflects exacerbation in a chronically rejecting graft. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 239-242.

Q: What is the initial event in serum sickness?

It occurs due to exposure to heterologous antigens.. ***Can lead to leukocytoclastic vasculitis*** - Serum sickness is characterized by the formation of **immune complexes**, which can trigger **leukocytoclastic vasculitis** affecting the blood vessels [1][2]. - Symptoms can include **rash, fever, and arthralgia**, typically occurring 1-3 weeks after exposure to the offending antigen [2]. *Can occur due to homologous antigen* - Serum sickness is usually a reaction to **heterologous** antigens, such as those from animal serum, not **homologous** ones. - Homologous antigens do not typically elicit the immune response seen in serum sickness; hence, this statement is incorrect. *Type 2 hypersensitivity* - Serum sickness is classified as a **Type III hypersensitivity** reaction due to the immune complex formation, not Type II [1]. - Type II is characterized by antibody-mediated destruction of **target cells**, which does not apply here. *Hypercomplementemia* - Serum sickness is associated with **hypocomplementemia** due to complement consumption from immune complex formation, not hypercomplementemia. - This can lead to **decreased complement levels** during the response, making this statement incorrect. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 214-216. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 172-173.

Q: Which genetic condition is considered the most lethal due to monosomy?

Autosomal monosomy. ***Autosomal monosomy*** - **Autosomal monosomy** is the most lethal form of monosomy because it involves the loss of an entire autosome, leading to a severe imbalance in gene dosage. [1] - The human body cannot typically survive with the loss of a whole autosome, resulting in early embryonic or fetal demise. [1] *Chromosomal monosomy* - This is a broader term that includes both **autosomal monosomy** and **sex chromosome monosomy**. - While many forms of chromosomal monosomy are lethal, **sex chromosome monosomy (e.g., Turner syndrome)** is survivable, making the general term "chromosomal monosomy" less specific for the *most lethal* condition. [1] *Autosomal trisomy* - **Autosomal trisomy** involves an extra copy of an autosome (e.g., Trisomy 21 for Down syndrome), which, while causing significant health issues, is generally less lethal than the complete loss of an autosome. [1] - Many individuals with autosomal trisomies can survive to birth and beyond, unlike most cases of autosomal monosomy. [1] *Chromosomal trisomy* - This refers to having an extra copy of any chromosome, including **autosomes** and **sex chromosomes**. - While conditions like **Trisomy 13 (Patau syndrome)** and **Trisomy 18 (Edwards syndrome)** are highly lethal, the presence of *extra* genetic material is typically less universally lethal than the *absence* of an entire autosome. [1] **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 168-169.

Q: Structure of chromosomes is studied by?

G-banding. ***G-banding*** - G-banding is the most commonly used method for the **detailed examination of chromosomes**, allowing visualization of banding patterns [1][2]. - It facilitates the identification of **chromosomal abnormalities** and is essential in **cytogenetic studies** [1][2]. *Q-banding* - Q-banding reveals a different pattern that is primarily used for **detection of specific chromosome markers** but is less common than G-banding. - It is more useful for cases requiring **fluorescent bright bands** but not for overall structural analysis. *C-banding* - C-banding specifically highlights the **centromeric regions** of chromosomes, not the overall structure. - It is limited in scope compared to G-banding since it doesn't provide a complete picture of chromosome morphology. *Brd V-staining* - Brd V-staining focuses on specific **DNA regions** and is related to the **visualization of viral DNA** in infected cells rather than chromosome structure. - It does not offer insights into the **general structural characteristics** of chromosomes like G-banding does. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 54-55. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 167-168.

Q: Diabetic foot is associated with following type of gangrene -

Wet gangrene. ***Wet gangrene*** - Diabetic foot commonly leads to **ischemia** and **infection** [1], resulting in wet gangrene characterized by moist, necrotic tissue. - This type of gangrene is associated with **rapid progression** and can result in systemic toxicity, making prompt treatment essential. *Fournier's gangrene* - This type of gangrene specifically affects the **perineal** region and is not directly associated with diabetic foot. - It usually arises from infections related to **perineal trauma** or surgical procedures. *Gas gangrene* - Caused by **Clostridium** species and typically follows a traumatic injury or surgical procedure, not specifically related to diabetes. - Presents with **crepitus** and rapid systemic symptoms, different from the chronic nature of diabetic ulcers. *Dry gangrene* - Associated with **chronic ischemia** and necrosis, it occurs in conditions like peripheral arterial disease, not primarily with infections seen in diabetic foot [1]. - It usually develops gradually without the sudden onset of symptoms characteristic of wet gangrene.

Question 1

Chemotaxis is mediated by-

Accepted Answer

Leukotriene B4 and C5a

Answer

Histamine

Answer

Leukotriene C4 and C3a

Answer

Bradykinin

Question 2

Interleukin responsible for Pyrexia is:

Accepted Answer

IL1

Answer

IL4

Answer

IL3

Answer

IL8

Question 3

Post-streptococcal glomerulonephritis (PSGN) is an example of which type of hypersensitivity?

Accepted Answer

Type -3 hypersensitivity

Answer

Type -1 hypersensitivity

Answer

Type -2 hypersensitivity

Answer

Type -4 hypersensitivity

Question 4

What is the number of antigens typically evaluated in comprehensive HLA matching for organ transplantation?

Accepted Answer

10

Answer

4

Answer

16

Answer

22

Question 5

What is the most common type of graft rejection?

Accepted Answer

Acute

Answer

Hyperacute

Answer

Chronic

Answer

Acute on chronic

Question 6

What is the initial event in serum sickness?

Accepted Answer

It occurs due to exposure to heterologous antigens.

Answer

It is associated with hypocomplementemia.

Answer

It is a type III hypersensitivity reaction.

Answer

It can lead to leukocytoclastic vasculitis.

Question 7

Which genetic condition is considered the most lethal due to monosomy?

Accepted Answer

Autosomal monosomy

Answer

Chromosomal monosomy

Answer

Autosomal trisomy

Answer

Chromosomal trisomy

Question 8

Which of the following is a chromosomal instability syndrome?

Accepted Answer

Bloom syndrome

Answer

Fanconi anemia

Answer

Ataxia-telangiectasia

Answer

None of the options

Question 9

Structure of chromosomes is studied by?

Accepted Answer

G-banding

Answer

C-banding

Answer

Q-banding

Answer

BrdU staining

Question 10

Diabetic foot is associated with following type of gangrene -

Accepted Answer

Wet gangrene

Answer

Dry gangrene

Answer

Gas gangrene

Answer

Fournier's gangrene

NEET-PG 2015 — Pathology