NEET-PG 2015 Practice Questions

Q: B cells are located in which region of lymph nodes?

Cortical follicles. ***Cortical follicles*** - **B cells** are predominantly found within the **cortical follicles** of lymph nodes, where they mature and become activated upon encountering antigens [2]. - These follicles can be primary (inactive) or secondary (active, containing **germinal centers** for B cell proliferation and differentiation). *Paracortical region* - The **paracortical region** is primarily occupied by **T cells** and is the site where T cells interact with antigen-presenting cells [1]. - While it's adjacent to B cell areas, it's not the primary location for B cells. *Medullary sinuses* - **Medullary sinuses** are channels in the medulla of the lymph node, containing macrophages and plasma cells, which are *differentiated B cells*. - They are not the primary residence for undifferentiated B cells. *Subcapsular region* - **Subcapsular region** is the space immediately beneath the capsule of the lymph node where lymph initially enters. - It contains macrophages and dendritic cells that sample antigens but is not a primary B cell zone.

Q: HLA-Cw6 is associated with

Psoriasis vulgaris. ***Psoriasis vulgaris*** - **HLA-Cw6** is the **strongest genetic risk factor** associated with an increased susceptibility to psoriasis vulgaris, particularly early-onset forms. - Its presence is linked to a more severe and widespread presentation of the disease. *Myasthenia gravis* - This autoimmune disorder is primarily associated with **HLA-DR3** and **HLA-B8**, and autoantibodies against the acetylcholine receptor. - While other HLA alleles may be involved, **HLA-Cw6** is not a primary or strong genetic association for myasthenia gravis. *Behcet's disease* - **HLA-B51** is the most significant genetic association with Behcet's disease, particularly in populations of Middle Eastern and East Asian descent. - Symptoms include **recurrent oral and genital ulcers**, **uveitis**, and skin lesions. *Pemphigus vulgaris* - This autoimmune blistering disease is strongly associated with **HLA-DR4** and **HLA-DRw6**, especially in individuals of Jewish descent. - It involves autoantibodies targeting **desmoglein 1 and 3**, leading to acantholysis within the epidermis.

Q: In which condition is Serum Amyloid Associated (SAA) protein most commonly found?

Chronic inflammatory states. ***Chronic inflammatory states*** [1][2] - Serum amyloid-associated protein is elevated in response to **chronic inflammation**, such as in rheumatic diseases and infections [1][2]. - It serves as a **biomarker** indicating systemic inflammation and is part of the **acute-phase response** [1]. *Chronic renal failure* - While renal failure can lead to amyloidosis, it is not a direct cause of serum amyloid-associated protein elevation. - **Renal impairment** is more associated with a decrease in clearance rather than production of amyloid proteins. *Alzheimer's disease* - Although amyloid plaques are a hallmark of Alzheimer's, they are related to **A-beta peptide**, not serum amyloid-associated protein. - Alzheimer's pathology primarily involves **neurodegeneration** rather than inflammatory response. *Malignant hypertension* - Malignant hypertension primarily affects the **vascular system** and does not directly involve the production of serum amyloid-associated protein. - It is characterized by end-organ damage, rather than a state of chronic inflammation. *Chronic inflammatory conditions like RA, TB & leprosy, osteomyelitis, ankylosing spondylitis, IBD, bronchiectasis, some tumors* [1][2] - While these conditions can be associated with systemic inflammation, they are too specific and do not comprehensively encompass the broader concept of **chronic inflammatory states**. - This option fails to highlight that serum amyloid-associated protein is a marker for **various chronic inflammatory states** beyond just those listed [1].

Q: Shrinking Lung Syndrome is seen in:

SLE. ***SLE*** - **Shrinking lung syndrome (SLS)** is a rare but recognized pulmonary manifestation of **systemic lupus erythematosus (SLE)** [1]. - It is characterized by **dyspnea**, **pleuritic chest pain**, and elevated diaphragms with reduced lung volumes, often without significant interstitial lung disease [1]. *Rheumatoid Arthritis* - While **rheumatoid arthritis** can cause various lung manifestations like **interstitial lung disease (ILD)**, pleural effusions, and rheumatoid nodules, **shrinking lung syndrome** is not typically associated with it [2]. - Lung disease in RA often involves **pulmonary fibrosis** or bronchiolitis, differing from the restrictive physiology of SLS. *Scleroderma* - **Scleroderma (Systemic Sclerosis)** commonly affects the lungs, primarily leading to **interstitial lung disease (ILD)** and **pulmonary hypertension** [1]. - **Shrinking lung syndrome**, with its characteristic restrictive pattern and elevated diaphragms, is not a typical presentation of lung involvement in scleroderma. *Sarcoidosis* - **Sarcoidosis** is characterized by the formation of **non-caseating granulomas**, primarily affecting the lungs and lymph nodes. - Lung involvement in sarcoidosis typically presents as **interstitial lung disease** or nodular infiltrates, not the distinct features of **shrinking lung syndrome** [3].

Q: The process by which antigen-specific B lymphocytes are selected and activated to proliferate and produce antibodies is called:

Clonal selection. ***Clonal selection*** - **Clonal selection** is the fundamental process by which an antigen-specific B lymphocyte is **selected** when its B cell receptor (BCR) recognizes and binds to a matching antigen. - This binding triggers the B cell to become **activated**, **proliferate** (undergo clonal expansion), and **differentiate** into plasma cells that produce antibodies specific to that antigen. - This process is the cornerstone of **adaptive immunity**, ensuring that only B cells with receptors matching the encountered antigen are stimulated to respond. *Class switching* - **Class switching** (isotype switching) occurs AFTER clonal selection and activation. - It allows already-activated B cells to change the **antibody class** they produce (from IgM to IgG, IgA, or IgE) while maintaining the **same antigen specificity**. - This process modifies effector functions but does NOT involve the initial selection and activation of antigen-specific B cells. *Group switching* - This is not a recognized term in immunology. - It does not describe any standard process of B cell activation or antibody production. *Hybridisation* - **Hybridization** refers to the formation of double-stranded nucleic acids from complementary strands or the creation of hybrid cells (e.g., hybridomas for monoclonal antibody production). - It is not the physiological process by which B lymphocytes are selected and activated in response to antigen exposure.

Q: In the context of immune response, which of the following cell types does not express MHC class II molecules?

NK cells. ***NK cells*** - **Natural Killer (NK) cells)** are innate lymphocytes that do **NOT express MHC class II molecules** under any circumstances. - NK cells use alternative recognition mechanisms (KIRs, activating receptors) to detect target cells, primarily recognizing the **absence of MHC class I** or stress-induced ligands. - They function in innate immunity without antigen presentation capability. - **This is the best answer** as NK cells never express MHC class II, making them distinctly different from professional APCs. *Cortical macrophages* - **Cortical macrophages** in lymphoid organs are professional **antigen-presenting cells (APCs)** that constitutively express **MHC class II molecules**. - They present processed antigens to CD4+ T helper cells, playing a crucial role in initiating adaptive immune responses. *Medullary macrophages* - **Medullary macrophages** are also professional APCs that constitutively express **MHC class II molecules**. - They participate in antigen presentation and immune surveillance within the medullary regions of lymphoid tissues. *Neutrophils* - Neutrophils are granulocytes that **typically do not constitutively express MHC class II molecules** in their resting state. - However, under certain inflammatory conditions with prolonged stimulation (IFN-γ, GM-CSF), neutrophils can be induced to express low levels of MHC class II. - While neutrophils generally lack MHC class II, **NK cells are the more definitive answer** as they never express MHC class II under any physiological or pathological conditions.

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: Which solid organ is considered to have the lowest risk of rejection during transplantation?

Liver. ***Liver*** - The liver has a unique immunologic environment, often referred to as **immunologic privilege**, which contributes to its lower rates of rejection compared to other transplanted solid organs. - It produces various **immunosuppressive factors** and has a high capacity for regeneration and repair, adapting more readily to the recipient's immune system. - The liver's **dual blood supply** (hepatic artery and portal vein) and tolerogenic properties make it the most immunologically privileged solid organ. *Pancreas* - **Pancreas transplantation** carries a high risk of rejection, with rejection rates significantly higher than liver transplantation. - Pancreatic tissue is highly **immunogenic** due to its endocrine and exocrine functions, requiring aggressive immunosuppression. - Often transplanted with kidney in diabetic patients, and rejection episodes are common. *Kidney* - Kidney transplantation is common, but it carries a significant risk of both **acute and chronic rejection**, requiring lifelong immunosuppression. - The kidney expresses various **MHC antigens** that are readily recognized by the recipient's immune system, making it more immunogenic than the liver. *Heart* - **Heart transplantation** is associated with a high risk of rejection due to the rich vascularity and immunogenicity of cardiac tissue. - It often requires aggressive immunosuppressive regimens to prevent both **acute cellular rejection** and **antibody-mediated rejection**.

Question 1

B cells are located in which region of lymph nodes?

Accepted Answer

Cortical follicles

Answer

Paracortical region

Answer

Subcapsular region

Answer

Medullary sinuses

Question 2

HLA-Cw6 is associated with

Accepted Answer

Psoriasis vulgaris

Answer

Behcet's disease

Answer

Pemphigus vulgaris

Answer

Myasthenia gravis

Question 3

In which condition is Serum Amyloid Associated (SAA) protein most commonly found?

Accepted Answer

Chronic inflammatory states

Answer

Alzheimer's disease

Answer

Malignant hypertension

Answer

Chronic renal failure

Answer

Acute myocardial infarction

Question 4

Shrinking Lung Syndrome is seen in:

Accepted Answer

SLE

Answer

Rheumatoid Arthritis

Answer

Scleroderma

Answer

Sarcoidosis

Question 5

The process by which antigen-specific B lymphocytes are selected and activated to proliferate and produce antibodies is called:

Accepted Answer

Clonal selection

Answer

Class switching

Answer

Group switching

Answer

Hybridisation

Question 6

In the context of immune response, which of the following cell types does not express MHC class II molecules?

Accepted Answer

NK cells

Answer

Cortical macrophages

Answer

Neutrophils

Answer

Medullary macrophages

Question 7

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 8

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 9

What is the most common type of graft rejection?

Accepted Answer

Acute

Answer

Hyperacute

Answer

Chronic

Answer

Acute on chronic

Question 10

Which solid organ is considered to have the lowest risk of rejection during transplantation?

Accepted Answer

Liver

Answer

Pancreas

Answer

Kidney

Answer

Heart

NEET-PG 2015

Anatomy

Dermatology

Internal Medicine

Microbiology

Pathology

Surgery