Hematopathology — MCQs

Hematopathology Indian Medical PG Practice Questions and MCQs

Question 521: A patient presents with splenomegaly, low RBC count, normal WBC and platelet count, and peripheral blood smear shows target cells. Repeated bone marrow aspiration is unsuccessful. What is the probable diagnosis?

A. Thalassemia
B. Chronic myeloid leukemia
C. Iron deficiency anemia
D. Myelofibrosis (Correct Answer)

Explanation: ### Explanation The correct diagnosis is **Myelofibrosis** (specifically Primary Myelofibrosis). [1] **1. Why Myelofibrosis is correct:** The hallmark of Myelofibrosis is the replacement of bone marrow with collagenous connective tissue (fibrosis). [3] This leads to two classic findings mentioned in the question: * **"Dry Tap":** Repeated unsuccessful bone marrow aspirations occur because the fibrotic marrow cannot be aspirated. * **Splenomegaly:** As the marrow fails, the body compensates via **Extramedullary Hematopoiesis**, primarily in the spleen, leading to massive enlargement. [3] * **Target Cells:** While typically associated with Thalassemia, target cells (codocytes) can also be seen in Myelofibrosis due to splenic dysfunction or abnormal erythropoiesis. **2. Why other options are incorrect:** * **Thalassemia:** While target cells are a classic feature, bone marrow aspiration is usually successful (hypercellular marrow) and does not result in a "dry tap." * **Chronic Myeloid Leukemia (CML):** CML presents with massive splenomegaly, but the WBC count is characteristically very high (leukocytosis with a left shift). Bone marrow is hypercellular, not fibrotic. * **Iron Deficiency Anemia (IDA):** IDA presents with microcytic hypochromic cells and pencil cells. It does not cause a "dry tap" or significant splenomegaly. **3. NEET-PG High-Yield Pearls:** * **The "Dry Tap" Triad:** Always consider Myelofibrosis, Hairy Cell Leukemia, or Aplastic Anemia when aspiration fails. * **Peripheral Smear:** Look for **Tear-drop cells (Dacrocytes)** and a **Leukoerythroblastic picture** (immature RBCs and WBCs), which are pathognomonic for Myelofibrosis. [1] * **Silver Stain:** Reticulin stain is used to confirm the degree of marrow fibrosis. * **Mutation:** Approximately 50-60% of cases are associated with the **JAK2 V617F** mutation. [2] **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 628-629. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 614-615. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 615-616.

Question 522: Which anticoagulant is used in coagulation studies?

A. Calcium citrate
B. EDTA
C. Sodium bromide
D. Trisodium citrate (Correct Answer)

Explanation: **Explanation:** **Trisodium citrate (3.2%)** is the anticoagulant of choice for coagulation studies (PT, APTT, and Fibrinogen levels). It works by **chelating calcium ions**, which are essential cofactors in the coagulation cascade. It is preferred because its action is easily reversible by adding calcium back to the plasma during testing. For accurate results, a precise **blood-to-anticoagulant ratio of 9:1** must be maintained; underfilling the tube leads to excess citrate, which falsely prolongs clotting times [1]. **Why other options are incorrect:** * **EDTA (Ethylenediaminetetraacetic acid):** While it is a potent calcium chelator, it is unsuitable for coagulation studies because it irreversibly inhibits certain clotting factors (like Factor V and VIII) and interferes with the end-point detection of fibrin formation. It is primarily used for CBC and peripheral smears. * **Calcium citrate:** This is not an anticoagulant; in fact, adding calcium to citrated plasma is the standard way to initiate the clotting process in a laboratory setting. * **Sodium bromide:** This has no role as a clinical anticoagulant. Historically, bromides were used as sedatives or antiepileptics. **High-Yield Clinical Pearls for NEET-PG:** * **Tube Color:** Trisodium citrate is found in the **Light Blue** top tube. * **Concentration:** 3.2% (0.109 mol/L) is the standard recommendation by the CLSI. * **Polycythemia Correction:** If a patient’s hematocrit is **>55%**, the volume of citrate must be adjusted (decreased) because there is less plasma relative to the anticoagulant, which can cause falsely elevated PT/APTT [1]. * **Platelet Function:** Citrate is also used for Platelet Aggregation Studies. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 625-626.

Question 523: A 60-year-old male patient presents with complaints of weakness and abdominal pain. General physical examination reveals marked splenomegaly and moderate hepatomegaly. Histopathologic findings are suggestive of leukoerythroblastosis. What condition is this patient most likely suffering from?

A. Primary myelofibrosis (Correct Answer)
B. Intestinal infarction
C. Sickle cell anemia
D. Chronic myeloid leukemia

Explanation: **Explanation:** The clinical presentation of a 60-year-old male with **marked splenomegaly** and **leukoerythroblastosis** is a classic description of **Primary Myelofibrosis (PMF)** [2]. **1. Why Primary Myelofibrosis is correct:** PMF is a Myeloproliferative Neoplasm (MPN) characterized by reactive bone marrow fibrosis (mediated by TGF-̢ from megakaryocytes) [2]. As the marrow becomes fibrotic, hematopoiesis shifts to the spleen and liver (**Extramedullary Hematopoiesis**), leading to massive splenomegaly [1]. The distorted marrow architecture forces immature cells into the peripheral blood, a phenomenon known as **Leukoerythroblastosis** (presence of nucleated RBCs and early granulocyte precursors) [1]. A peripheral smear would also typically show **Dacrocytes** (tear-drop RBCs) [1]. **2. Why the other options are incorrect:** * **Intestinal Infarction:** This presents as an acute surgical abdomen with severe pain and metabolic acidosis, not chronic splenomegaly or leukoerythroblastosis. * **Sickle Cell Anemia:** While it causes splenomegaly in children, repeated splenic infarcts lead to **autosplenectomy** (shrunken, fibrotic spleen) by adulthood [3]. It does not typically present with leukoerythroblastosis. * **Chronic Myeloid Leukemia (CML):** While CML presents with splenomegaly and a hypercellular marrow, the peripheral smear shows a "spectrum of myeloid cells" (myelocytes, metamyelocytes) but lacks the prominent fibrosis and dacrocytes characteristic of PMF. **Clinical Pearls for NEET-PG:** * **Hallmark Triad of PMF:** Massive splenomegaly + Tear-drop cells (Dacrocytes) + Leukoerythroblastosis [1]. * **Dry Tap:** Bone marrow aspiration often results in a "dry tap" due to extensive fibrosis (Silver stain/Reticulin stain is used for diagnosis). * **Mutation:** Approximately 50-60% of cases are associated with the **JAK2 V617F** mutation. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 628-629. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 615-616. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 644-645.

Question 524: Mean corpuscular hemoglobin concentration (MCHC) is normal in all of the following conditions except?

A. Iron deficiency anemia (Correct Answer)
B. Megaloblastic anemia
C. Hemolytic anemia
D. Aplastic anemia

Explanation: The **Mean Corpuscular Hemoglobin Concentration (MCHC)** represents the average concentration of hemoglobin in a given volume of packed red blood cells. It is calculated as: *(Hemoglobin / Hematocrit) × 100*. **1. Why Iron Deficiency Anemia (IDA) is the correct answer:** In IDA, there is a defect in heme synthesis, leading to **hypochromic microcytic anemia**. As the synthesis of hemoglobin is significantly impaired relative to the cell size, the concentration of hemoglobin within the RBC decreases [1]. Therefore, **MCHC is characteristically low** in IDA. **2. Analysis of incorrect options:** * **Megaloblastic Anemia:** This is a macrocytic anemia. While the cells are large (high MCV), the hemoglobin content increases proportionately to the cell size [2]. Thus, the **MCHC remains normal** (normochromic). * **Aplastic Anemia:** This is a normocytic normochromic anemia. Since there is a primary failure of production in the bone marrow but no defect in hemoglobin synthesis itself, the **MCHC remains normal** [4]. * **Hemolytic Anemia:** Most hemolytic anemias (like Sickle Cell or G6PD deficiency) are normocytic and normochromic, maintaining a **normal MCHC** [3]. **Clinical Pearls for NEET-PG:** * **High MCHC:** This is a classic diagnostic marker for **Hereditary Spherocytosis**. Because spherocytes are "tight" cells with a reduced surface area-to-volume ratio, the hemoglobin is more concentrated. * **Low MCHC:** Primarily seen in IDA, Sideroblastic anemia, and Thalassemia (Hypochromic states) [1]. * **MCHC vs. MCH:** MCH (Mean Corpuscular Hemoglobin) measures the *weight* of Hb per cell, while MCHC measures the *concentration*. MCHC is considered a more accurate reflection of "chromicity" on a peripheral smear. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 590-591. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 594-595. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 652-654. [4] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 595-596.

Question 525: Schistocyte is/are found in:

A. Thrombotic thrombocytopenic purpura (TTP)
B. March hemoglobinuria
C. Severe iron deficiency anemia
D. All of the above (Correct Answer)

Explanation: **Explanation:** Schistocytes are fragmented parts of red blood cells (RBCs) formed when the RBC membrane is mechanically severed or damaged [2]. The underlying mechanism is usually **Microangiopathic Hemolytic Anemia (MAHA)** or direct physical trauma to the cells. 1. **Thrombotic Thrombocytopenic Purpura (TTP):** This is a classic cause of MAHA [1]. Microthrombi (platelet plugs) form in small vessels. As RBCs attempt to squeeze through these narrowed passages, they are "sliced" by fibrin strands or thrombi, resulting in schistocytes (helmet cells, triangle cells) [2]. 2. **March Hemoglobinuria:** This occurs due to repetitive mechanical trauma to RBCs as they pass through the small vessels of the soles during prolonged forceful activities (like marching or marathon running). The physical impact crushes the RBCs, leading to fragmentation. 3. **Severe Iron Deficiency Anemia (IDA):** While IDA is typically characterized by microcytic hypochromic cells, in **severe** cases, the RBCs become extremely thin, fragile, and "pencil-shaped." These fragile cells are prone to fragmentation during circulation, leading to the presence of schistocytes. **Clinical Pearls for NEET-PG:** * **Diagnostic Threshold:** The presence of **>1% schistocytes** on a peripheral smear is highly suggestive of MAHA (TTP, HUS, or DIC). * **Differential Diagnosis:** Other high-yield causes include **DIC** (Disseminated Intravascular Coagulation), **HELLP syndrome**, and **Prosthetic Heart Valves** (Waring Blender Syndrome). * **Morphology:** Schistocytes lack central pallor and often have pointed ends (helmet cells). If you see schistocytes + low platelets, always suspect TTP/HUS first [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 947-948. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 540-541.

Question 526: What is the Philadelphia chromosome?

A. Chromosome 9-22 translocation (Correct Answer)
B. Chromosome 5-9 translocation
C. An absent marker indicating a bad prognosis
D. A prognostic factor in Acute Lymphoblastic Leukemia (ALL)

Explanation: The **Philadelphia chromosome (Ph)** is a hallmark cytogenetic abnormality in hematopathology, specifically associated with Chronic Myeloid Leukemia (CML) [1]. ### **Explanation of the Correct Answer** **Option A** is correct because the Philadelphia chromosome is a shortened chromosome 22 resulting from a **reciprocal translocation between chromosomes 9 and 22 [t(9;22)(q34;q11)]** [1], [3]. This translocation fuses the *ABL1* proto-oncogene on chromosome 9 with the *BCR* (Breakpoint Cluster Region) gene on chromosome 22. The resulting **BCR-ABL1 fusion gene** encodes a chimeric protein with constitutive **tyrosine kinase activity**, which drives uncontrolled cellular proliferation and inhibits apoptosis [2], [3]. ### **Analysis of Incorrect Options** * **Option B:** There is no classic "5-9 translocation" associated with a named diagnostic chromosome in standard hematopathology. * **Option C:** The Philadelphia chromosome is a **present** marker, not an absent one. In CML, its presence is diagnostic, and its disappearance during treatment (cytogenetic response) indicates a favorable prognosis. * **Option D:** While Ph+ ALL exists and is a poor prognostic factor, the question asks "What is" the chromosome itself. Option A provides the fundamental definition. (Note: In the context of some exams, D could be considered a true statement, but A is the definitive structural description). ### **High-Yield Clinical Pearls for NEET-PG** * **Disease Association:** Found in >95% of CML cases, 25-30% of adult ALL, and 2-5% of pediatric ALL. * **Molecular Weight:** The fusion protein is **p210** in CML and **p190** in ALL (associated with a poorer prognosis in ALL). * **Targeted Therapy:** **Imatinib (Gleevec)**, a tyrosine kinase inhibitor (TKI), specifically targets this protein and is the first-line treatment. * **Diagnosis:** Detected via Karyotyping, FISH (fluorescence in situ hybridization), or RT-PCR [1]. **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. 225-226. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, p. 624. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 624-625.

Question 527: A WBC count of more than 1,00,000 cells/cc of blood indicates which of the following?

A. Leukopenia
B. Leukoplakia
C. Leukocytosis
D. Leukemia (Correct Answer)

Explanation: **Explanation:** The correct answer is **Leukemia**. In clinical hematology, a Total Leukocyte Count (TLC) exceeding **1,00,000 cells/mm³** (hyperleukocytosis) is a hallmark of leukemias, particularly Chronic Myeloid Leukemia (CML) [2] and certain acute leukemias (AML/ALL). While "leukocytosis" refers to any elevation above the normal range (4,000–11,000 cells/mm³), such extreme elevations are rarely seen in reactive conditions and strongly point toward a primary neoplastic proliferation of white blood cells [1]. **Analysis of Options:** * **Leukopenia (A):** This refers to a **decrease** in the total WBC count below the normal range (usually <4,000 cells/mm³). * **Leukoplakia (B):** This is a clinical term for a **white patch or plaque** on a mucous membrane (e.g., oral cavity) that cannot be rubbed off; it is a precancerous condition and unrelated to blood counts. * **Leukocytosis (C):** While technically correct (as the count is high), it is a non-specific term. Reactive leukocytosis (e.g., infections) typically stays below 50,000 cells/mm³ [1]. When the count crosses 1,00,000, it is specifically categorized as **Hyperleukocytosis**, which is most commonly associated with Leukemia. **High-Yield Clinical Pearls for NEET-PG:** * **Leukemoid Reaction:** A reactive increase in WBCs (usually <1,00,000) mimicking leukemia [1]. It is differentiated from CML by a **high Leukocyte Alkaline Phosphatase (LAP) score** and the absence of splenomegaly or Philadelphia chromosome. * **Leukostasis:** A medical emergency occurring when extremely high blast counts (usually >1,00,000) increase blood viscosity, leading to tissue hypoxia, CNS symptoms, or pulmonary distress. * **CML:** Characterized by the "full spectrum" of myeloid cells (myelocytes, metamyelocytes, etc.) and a prominent basophilia [2]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 580-581. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 624-625.

Question 528: Mutation of which of the following genes is most important in paroxysmal nocturnal hemoglobinuria?

A. Decay accelerating factor (DAF)
B. Membrane inhibitor of reactive lysis (MIRL)
C. Glycosyl phosphatidyl inositol (GPI) (Correct Answer)
D. CD8 binding protein

Explanation: ### Explanation **Correct Answer: C. Glycosyl phosphatidyl inositol (GPI)** **Mechanism:** Paroxysmal Nocturnal Hemoglobinuria (PNH) is an acquired clonal hematopoietic stem cell disorder [2]. The fundamental defect is an **acquired somatic mutation** in the **PIGA gene** (Phosphatidylinositol Glycan class A) [2]. This gene is essential for the synthesis of the **GPI-anchor**, a glycolipid "hook" that attaches specific proteins to the surface of blood cells. Without a functional GPI-anchor, cells lack protective surface proteins, making them vulnerable to complement-mediated lysis [1]. **Analysis of Incorrect Options:** * **A & B (DAF/CD55 and MIRL/CD59):** These are the specific proteins that are *missing* on the cell surface in PNH [1]. **DAF (CD55)** inhibits C3 convertase, and **MIRL (CD59)** inhibits the Membrane Attack Complex (MAC). While their absence causes the clinical symptoms (hemolysis), the **primary mutation** is in the GPI-anchor synthesis (PIGA gene), not in the genes for DAF or MIRL themselves. * **D (CD8 binding protein):** This is not involved in the pathogenesis of PNH. **High-Yield Clinical Pearls for NEET-PG:** * **Triad of PNH:** Hemolytic anemia (intravascular), Pancytopenia, and Venous thrombosis (often in unusual sites like the hepatic vein—Budd-Chiari syndrome) [1]. * **Diagnosis:** The gold standard is **Flow Cytometry**, which demonstrates the absence of CD55 and CD59 on RBCs, WBCs, or granulocytes [1]. * **Ham’s Test & Sucrose Lysis Test:** These are older screening tests (now largely replaced by flow cytometry). * **Treatment:** **Eculizumab**, a monoclonal antibody that targets the C5 complement protein, is the treatment of choice to prevent hemolysis. * **Association:** PNH is closely linked with **Aplastic Anemia** and may transform into **Acute Myeloid Leukemia (AML)**. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 650-651. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 601-602.

Question 529: Increased bleeding time is seen in all of the following conditions except:

A. Thrombocytopenia
B. Von Willebrand disease
C. Hemophilia (Correct Answer)
D. Ehlers-Danlos syndrome

Explanation: **Explanation:** The **Bleeding Time (BT)** is a clinical test that assesses the **primary hemostatic pathway**, which involves the interaction between the vascular wall and platelets (adhesion and aggregation). Any defect in platelet number, platelet function, or vessel wall integrity will prolong the BT [4]. **1. Why Hemophilia is the correct answer:** Hemophilia (A or B) is a disorder of **secondary hemostasis** (coagulation cascade). It involves deficiencies in clotting factors (Factor VIII or IX) [1]. Since primary hemostasis (platelet plug formation) remains intact in Hemophilia, the **Bleeding Time is characteristically normal**. Instead, these patients show a prolonged Activated Partial Thromboplastin Time (aPTT) [2]. **2. Why the other options are incorrect:** * **Thrombocytopenia:** A decrease in platelet count directly impairs the formation of the primary platelet plug, leading to an increased BT [4]. * **Von Willebrand Disease (vWD):** vWF is essential for platelet adhesion to the subendothelium [3]. Its deficiency or dysfunction impairs primary hemostasis, thus increasing BT. (Note: vWD also increases aPTT because vWF stabilizes Factor VIII). * **Ehlers-Danlos Syndrome:** This is a connective tissue disorder causing defective collagen in the vessel walls. Poor vascular support leads to "Vascular Purpura" and an increased BT despite normal platelet function [5]. **High-Yield NEET-PG Pearls:** * **BT** = Platelet/Vessel Wall function (Primary Hemostasis) [4]. * **PT/aPTT** = Coagulation Factors (Secondary Hemostasis). * **Bernard-Soulier Syndrome & Glanzmann Thrombasthenia:** Both are platelet function disorders that present with **increased BT** but normal platelet counts (except for mild thrombocytopenia in Bernard-Soulier) [3]. * **Rule of Thumb:** If the question mentions deep muscle hematomas or hemarthrosis, think Secondary Hemostasis (Normal BT). If it mentions petechiae or mucosal bleeding, think Primary Hemostasis (Increased BT). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 670-671. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 623-624. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 668-669. [4] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 619-620. [5] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 664-665.

Question 530: Which of the following cells are involved in the process of efferocytosis?

A. Macrophages (Correct Answer)
B. T lymphocytes
C. B lymphocytes
D. NK cells

Explanation: **Explanation:** **Efferocytosis** is the physiological process by which apoptotic (dying) cells are recognized, engulfed, and removed by phagocytic cells before they can undergo secondary necrosis and release pro-inflammatory contents. 1. **Why Macrophages are correct:** Macrophages are the primary "professional" phagocytes responsible for efferocytosis [1]. The process involves a "find-me" signal (e.g., ATP, UTP) released by the apoptotic cell, followed by "eat-me" signals (most notably the flipping of **Phosphatidylserine** from the inner to the outer leaflet of the plasma membrane) [1]. Macrophages recognize these signals via specific receptors (like TAM receptors), leading to silent, anti-inflammatory clearance mediated by the release of cytokines like **TGF-β and IL-10**. 2. **Why other options are incorrect:** * **T and B Lymphocytes:** These are cells of the adaptive immune system involved in antigen recognition and antibody production [2]. They do not possess the specialized phagocytic machinery required for the engulfment of whole apoptotic bodies. * **NK Cells:** These are innate lymphoid cells specialized in killing virally infected or tumor cells through the release of perforins and granzymes; they are not primary phagocytes. **High-Yield Facts for NEET-PG:** * **Phosphatidylserine (PS):** The most important "eat-me" signal. In healthy cells, it is restricted to the inner membrane by flippases [1]. * **Anti-inflammatory nature:** Unlike necrosis, which causes inflammation, efferocytosis is actively **anti-inflammatory** [1]. * **Clinical Correlation:** Defective efferocytosis is linked to the pathogenesis of autoimmune diseases like **Systemic Lupus Erythematosus (SLE)**, where uncleared apoptotic debris provides a source of self-antigens. * **Other Efferocytes:** While macrophages are the "professionals," "amateur" efferocytes include epithelial cells and fibroblasts. **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. 67-69. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 579-580.

Practice by Chapter

Anemias: Classification and Approach

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Hemolytic Anemias

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Myeloproliferative Neoplasms

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Myelodysplastic Syndromes

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Acute Leukemias

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Chronic Leukemias

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Lymphomas and Lymphoid Neoplasms

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Plasma Cell Disorders

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Bleeding Disorders

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Thrombotic Disorders

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