Which disease is associated with the CD59 marker?
Factor V Leiden thrombophilia is caused by mutation in which of the following factors?
Which marker is commonly associated with positivity in follicular lymphoma?
Which of the following statements about cross-matching of blood is false?
The Ham test is specifically used for diagnosing paroxysmal nocturnal hemoglobinuria (PNH) and is based upon:
Which of the following is typically expected in a case of Microcytic Hypochromic anemia?
Indirect Coombs test detects:
Which type of anemia is most commonly characterized by marked poikilocytosis and anisocytosis on peripheral blood smear?
Sezary cells show which type of nucleus?
Osmotic fragility test is commonly used for which of the following conditions?
Explanation: ***PNH*** - The **CD59 marker** is associated with **Paroxysmal Nocturnal Hemoglobinuria (PNH)**, a condition characterized by the loss of glycosylphosphatidylinositol (GPI) anchored proteins [1]. - It protects red blood cells from **complement-mediated lysis**, and its absence leads to hemolysis and thrombosis in patients with PNH [1,4]. *PTEN* - The **PTEN gene** is a tumor suppressor associated with various cancers and is not related to CD59. - It is primarily involved in the **regulation of the Akt signaling pathway**, not in complement regulation. *BRR* - **BRR (Birt-Hogg-Dubé syndrome)** is linked to folliculin and does not involve CD59. - This genetic condition is characterized by **skin tumors** and renal tumors, unrelated to the complement system. *Cowden syndrome* - **Cowden syndrome** is associated with mutations in the PTEN gene, relating to **hamartomas** and breast cancer risk, not CD59. - It affects multiple systems but does not involve **complement regulatory proteins** like CD59. **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.
Explanation: ***Factor V*** - Leiden thrombophilia is specifically caused by a **mutation in the Factor V gene**, leading to resistance to activated protein C [1]. - This results in an increased risk of **venous thromboembolism** due to uncontrolled coagulation [1]. *Factor X* - Factor X is crucial for the coagulation cascade but is **not implicated in Leiden thrombophilia**; it does not involve a mutation. - Deficiencies or dysfunctions in Factor X lead to different bleeding disorders rather than thrombophilia. *Factor VII* - Factor VII deficiency typically results in **hemorrhagic conditions**, and does not relate to the **thrombotic risks** of Leiden thrombophilia. - It involves **extrinsic pathway coagulation**, which is distinct from the resistance seen in Factor V Leiden. *Factor IX* - Factor IX is associated with **Hemophilia B** and does not play a role in Leiden thrombophilia. - Its mutation results in bleeding tendencies, contrasting with the **thrombotic risk** of Leiden thrombophilia. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 133-134.
Explanation: ***Bcl-2*** - **Follicular lymphoma** is characterized by the overexpression of the **Bcl-2 protein**, which inhibits apoptosis, leading to the survival of malignant B cells [1][3]. - The **Bcl-2 gene** is often involved in the **t(14;18)** chromosomal translocation, which is a hallmark of this lymphoma [1][3][4]. *Bcl-6* - Although **Bcl-6** can be expressed in some lymphomas, it is primarily associated with **diffuse large B-cell lymphoma**, not follicular lymphoma. - **Bcl-6** is involved in **germinal center formation** and its positivity does not indicate follicular lymphoma specifically. *Bcl-1* - **Bcl-1** (also known as **CCND1**) is primarily associated with **mantle cell lymphoma** and is not a characteristic marker for follicular lymphoma. - It is linked to the **t(11;14)** translocation, which is distinct from the genetic alterations seen in follicular lymphoma. *None of the above* - This option is incorrect as **Bcl-2 positivity** is definitive for follicular lymphoma [2]. - The presence of other markers like **Bcl-6** or **Bcl-1** does not negate the expression of Bcl-2 in this lymphoma type. **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. 602-604. [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. 604. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 561-562. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 310-311.
Explanation: ***Donor serum is tested against recipient packed cells*** - This statement is **FALSE** and describes a **minor crossmatch**, which is rarely performed in modern transfusion practice. - The minor crossmatch tests donor antibodies against recipient cells, but this is not standard practice because donor plasma is significantly diluted during transfusion, making clinically significant reactions rare. - Modern blood banking focuses on the **major crossmatch** as the critical safety measure. *Recipient serum is tested against donor packed cells* - This statement is **TRUE** and accurately describes the **major crossmatch**, which is the standard and most critical pre-transfusion compatibility test. - The major crossmatch detects antibodies in the recipient's serum that could react with donor red blood cell antigens, preventing potentially fatal hemolytic transfusion reactions. *Mandatory in all cases except emergency* - This statement is **TRUE**. Crossmatching is mandatory for safe transfusion practice. - In life-threatening emergencies where delay could be fatal, uncrossmatched O-negative (universal donor) blood may be given, but this is a rare exception. *Involves visible agglutination* - This statement is **TRUE**. A positive crossmatch indicating incompatibility is identified by **visible agglutination** or **hemolysis**. - These visible reactions occur when recipient antibodies bind to donor red blood cell antigens, signaling that transfusion would cause a severe reaction.
Explanation: ***Complement*** - The HAM test is based on the activation of the **complement system** which enhances the opsonization and clearance of immune complexes [1]. - It is used in the diagnosis of certain conditions, notably those associated with **hemolytic anemia** due to complement fixation. *GPI Anchor Proteins* - GPI anchor proteins are involved in anchoring proteins to cell membranes but are **not related to the HAM test**. - This oes not explain the **mechanism** or purpose of the HAM test. *Mannose binding proteins* - Mannose binding lectins play a role in **innate immunity** but are not the basis of the HAM test. - They function in the **opsonization of pathogens**, which is unrelated to the complement activation aspect of the HAM test. *Spectrin protein* - Spectrin is a cytoskeletal protein that contributes to the integrity of cell membranes, particularly in red blood cells. - It does not relate to the **mechanism of the HAM test**, which focuses on complement involvement. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 99-100.
Explanation: ***Reduced total RBC distribution width*** - Microcytic hypochromic anemia typically shows **increased RBC distribution width (RDW)** due to varied sizes of red blood cells, indicating a diverse population in response to microcytic anemia [1]. - A **reduced RDW** would suggest a more uniform red blood cell population, which is not characteristic of this type of anemia. *Normal Ferritin levels* - Ferritin levels are usually **low** in microcytic hypochromic anemia, indicating **iron deficiency** [1]. - Normal ferritin might suggest other types of anemia rather than the iron deficiency expected in microcytic anemia. *Reduced serum Iron* - Serum iron is generally **low** in microcytic hypochromic anemia due to **iron deficiency**, making this an expected finding [1]. - The presence of reduced serum iron supports the diagnosis and is not inconsistent with this type of anemia. *Increased TIBC* - TIBC (Total Iron Binding Capacity) is typically **increased** in microcytic anemia due to low iron stores, reflecting the body's attempt to maximize iron uptake. - An increased TIBC aligns with iron deficiency anemia, which is a common cause of microcytic hypochromic anemia [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 590-591.
Explanation: ***Antibodies in the serum*** - The **indirect Coomb's test** is designed to detect the presence of **antibodies** against red blood cells (RBCs in the serum) before transfusion or during pregnancy [1]. - It is crucial in identifying **hemolytic disease of the newborn** (HDN) and ensuring safe blood transfusions [1]. *Antibodies attached to RBC Surface* - This scenario describes the **direct Coomb's test**, which identifies antibodies that are already bound to **RBCs**. - Direct testing assesses conditions like **autoimmune hemolytic anemia**, not the serum. *Antigens attached to RBC Surface* - This option suggests evaluating **antigens** present on the surface of RBCs, which is not the purpose of the indirect Coomb's test. - Antigens are important in blood typing and compatibility assessments, but this test focuses on antibodies. *Antigens in the serum* - Indirect Coomb's does not detect **antigens** but rather the **antibodies** related to those antigens. - Additionally, serum testing for antigens is not a standard procedure for assessing transfusion compatibility. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 627-628.
Explanation: ***Iron deficiency anaemia*** - Characterized by **poikilocytosis** (abnormal shapes) and **anisocytosis** (variation in red blood cell sizes), which are common findings in iron deficiency [1]. - Typically results in **microcytic hypochromic anemia** [1], distinguishing it from other types of anemia. *Nutritional deficiency anaemia* - May present with various blood cell morphology but does not specifically exhibit **poikilocytosis** and **anisocytosis** characteristic of iron deficiency anemia. - Usually includes deficiencies like **vitamin B12** or **folate**, which result in **macrocytic anemia** instead. *Megaloblastic anaemia* - Primarily caused by deficiency of **vitamin B12** or **folate**, leading to large, immature red blood cells (megaloblasts) rather than varied shapes and sizes. - Associated with **hypersegmented neutrophils** in the blood smear, which differentiates it from iron deficiency anemia. *Thalassemia* - Characterized by **microcytic hypochromic red blood cells** and often involves **target cells** rather than generalized poikilocytosis and anisocytosis. - Typically presents with **hemolytic anemia** but does not show the same variability in cell shapes and sizes as seen in iron deficiency anemia. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 590-591.
Explanation: ***Cerebriform*** - **Sezary cells** are characterized by their distinctive **cerebriform nuclei**, giving them an irregular, convoluted appearance [1,2]. - This finding is a hallmark of **cutaneous T-cell lymphoma** and emphasizes their potential malignancy [1,2]. *Round* - Round nuclei do not reflect the typical morphology of **Sezary cells**, which are noted for their **irregular shape**. - Other lymphocytes may exhibit round nuclei, but this does not specifically indicate a **Sezary cell** presence. *Pleomorphic* - While some malignant cells might show **pleomorphic nuclei**, Sezary cells uniquely showcase **cerebriform nuclei** rather than varying shapes [1,2]. - Pleomorphic is not a defining characteristic of **Sezary cells**, making this description inaccurate. *Eosinophillic* - Eosinophilic refers to cells that stain positively for **eosin**, typically associated with **eosinophils**, which is not relevant to **Sezary cells**. - Sezary cells are more about their **nuclear morphology** and less about eosinophilic staining characteristics. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 564-565. [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. 613-614.
Explanation: ***Hereditary spherocytosis*** - The **osmotic fragility test** helps in diagnosing hereditary spherocytosis, where **spherical red blood cells** are more prone to hemolysis in hypotonic solutions [1][2]. - This condition is characterized by **spherocytes** (abnormally shaped RBCs) leading to increased osmotic fragility [1][3]. *Megaloblastic anemia* - Megaloblastic anemia is primarily associated with **deficiencies in B12 or folate**, affecting the size and maturation of red blood cells, not their osmotic fragility. - The diagnosis focuses on **serum vitamin levels** and **bone marrow examination** rather than osmotic fragility. *Iron deficiency anemia* - Iron deficiency anemia features **microcytic** and **hypochromic RBCs**, and its diagnosis relies on **iron studies**, not osmotic fragility tests. - The osmotic fragility test does not reveal significant changes in red blood cells for this condition. *Aplastic anemia* - Aplastic anemia involves **pancytopenia** due to bone marrow failure and does not typically show altered osmotic fragility. - The diagnosis is confirmed through **bone marrow biopsy**, not by assessing osmotic fragility. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 597-598. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 640-641. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, p. 638.
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