Hematology and Immunology

Frage	Antworten
What cells are derived from pluripotent hematopoietic stem cells? (think- what are the components of a CBC with differential?)	Proerythrocyte-> Reticulocyte-> Erythrocytes (RBCs) Lymphoid stem cells -> lympboblast -> lymphocytes (T and B cells) B cells can go on to become plasma cells. Myeloid stem cell -> Monoblast -> Monocytes. Myeloid stem cell -> Megarkaryoblast -> Megakaryocyte -> Platelets. Myeloid stem cell -> Myeloblast -> Promyelocyte -> Myelocyte -> Metamyelocyte -> Band cell -> Neutrophils, Eosinophils, Basophils
A 17-year old girl notices a swollen lymph node in her neck and biopsy shows Reed-Sternberg cells. What disease is this?	Hodgkin disease.
A 7 year old girl has an elevated white blood cell count, easy bruising and fatigue. What should she be evaluated for?	Acute lymphoblastic leukemia, the most common type of cancer in children under age 15
A newborn baby shows signs of anemia and jaundice within the first 24 hours of life. What might he have?	Hemolytic disease of the newborn (due to Rh factor incompatibility or ABO blood group incompatibility between mother and infant)
A woman starts to feel exhausted and light-headed a week after beginning a course of penicillin. What is this?	Autoimmune hemolytic anemia, which is a type 2 hypersensitivity reaction to the drug (the body forms antibodies to the drug, the antibody binds the drug on the RBCs, resulting in hemolysis)
A patient develops an itchy, raised, red rash 2 to 3 days after using a new brand of detergent. What is this?	Contact dermatitis, which is a type IV hypersensitivity reaction.
A patient begins receiving a blood transfusion. He develops fever, chills, hypotension and DIC. What happened?	Acute hemolytic transfusion reaction. The patient received RBCs with an antigen to which he had previously formed alloantibodies, such as ABO antigens or Kidd antigen.
A child receives a bone marrow transplant from his healthy brother. Several months later he develops a rash, jaundice and diarrhea. What is this reaction?	Graft-versus-host disease. (GVHD)
An alcoholic man presents with anemia. Would you expect his mean corpuscular volume (MCV) to be high or low? What is he probably deficient in?	Expect him to have megaloblastic anemia with a high MCV, either as a direct result from the chronic alcohol use or secondary to concomitant vitamin B12 and or folate deficiency.
A 53-year old man has been feeling tired lately. His hemoglobin level is 8.0. What should you be sure to order?	Check for occult blood in the stool and order a colonoscopy to evaluate for possible colorectal cancer.
An elderly woman has lung cancer. What might characterize her anemia for chronic disease?	-Decreased RBC life span. -Microcytosis. -Impaired iron metabolism -Possible refractoriness or lack of response to erythropoietin.
What infection are blood-transfusion recipients at greatest risk for?	Bacterial contamination (not HIV or hepatitis)
What causes TRALI (transfusion related acute lung injury?)	The donor's antileukocyte antibodies react with the recipient's leukocytes.
What characterizes TRALI clinically?	Pulmonary edema, fever, tachypnea, cyanosis.
What is the most common metabolic side effect of massive blood transfusion?	Alkalosis due to the citrate anticoagulant converting to bicarbonate in the liver.
What correlates to the severity of a febrile non-hemolytic transfusion reaction?	The number of leukocytes present in the blood component.
What is the risk of FFP transfusion?	Allergic/anaphylactic reactions.
What causes these allergic reactions?	The patient has IgE antibodies against plasma proteins in the transfused blood.
What type of patients will have anaphylactic reactions?	Patients who are IgA deficient and have preformed IgA antibodies.
A 1-year old child is brought to the pediatrician by her mother with complaints of several episodes of turning blue during playing. The child squats down when she turns blue and then a few seconds later she resumes playing. What congenital heart disease can cause this symptom?	Tetralogy of Fallot (Tet spells)
What is hemoglobin H disease?	The form of a-thalassemia in which patient lacks three a-globin chains, leading to production of B tetramers. This result in mild to moderate microcytic hypochromic anemia with target cells and Heinz bodies, hepatosplenomegaly and jaundice.
What is hemoglobin Barts?	All four a-globin genes are missing; leading to complete absence of a-globin chains and production of y-tetramets and resulting in fetal anemia, hydrops fetalis, and often intrauterine fetal demise. In both Hb H and Hb Barts, the abnormal tetramers have a higher affinity for oxygen than normal hemoglobin resulting in impaired oxygen delivery to tissues.
What are schistocytes and how do they form?	Schistocytes are fragmented RBCs, resulting from mechanical/sheering damage to RBCs, often seen in DIC or with mechanical heart valves.
What are the two categories of autoimmune hemolytic anemias?	Warm agglutinin, (IgG), typically more chronic, seen in chronic disease, SLE, CLL and drugs; primarily extravascular hemolysis Cold agglutinin (IgM)- acute anemia, seen in infections such as mycoplasma and mononucleosis.
Mechanistically, what are two ways that hemolysis occurs?	Intravascular (as the name implies, RBCs destroyed within the blood vessels), often more severe anemia; labs show hemoglobinemia, hemoglobinuria, and low haptoglobin (eg microangiopathic, ABO incompatibility) Extravascular (aka within the reticuloendothelial system), labs show elevated serum bilirubin and lactate dehydrogenase (LDH), eg RBC membrane defects.
Define erythrocytosis	An increased number of RBCs (eg as seen in polycythemia vera)
What coagulation factor is deficient in hemophilia A?	Factor VIII
Which coagulation factor is deficient in hemophilia B?	Factor 9
What lab findings characterize DIC?	High-prothrombin time (PT), partial thromboplastin time (PTT), fibrin split products (D-dimer) Low-platelet count
In ABO blood groups, what is Landsteiner rule?	If you lack the RBC antigen, you make the antibody to it (type A antigen blood has anti B antibodies)
What blood type is the universal recipient?	Type AB, because they have formed neither anti-A or anti-B antibodies in their plasma.
What does Rh+ indicate?	The presence of the D antigen on the person's RBCs
What is Rh immune globulin?	Immunoglobin G (IgG) anti-D antibodies in a purified preparation; given to Rh- mothers in pregnancy to prevent hemolytic disease of the newborn.
What does the direct antiglobulin test (DAT or direct Coombs) detect?	The DAT detects the presence of antibodies coating the patient's RBC surface in vivo
What does the indirect antiglobulin test (IAT or indirect Coombs) detect?	The IAT detects RBC antibodies in the patient's serum (in vitro binding of IgG)
Describe the process for performing both the DAT and IAT	DAT: The patient's RBCs are washed (removing the patient's plasma) and then incubated with Coombs reagent (anti-human globulin). If agglutinantion of the RBCs occurs the test is positive, indicating that antibodies on the surface of the patient's RBCs were present and bound the Coombs reagent in order to agglutinate. IAT- The patient's serum is extracted (RBCs removed) and incubated with standard RBCs that have known antigenicity. Then the Coombs reagent is added. If agglutination occurs the test is positive indicating presence of antibodies in the patient's serum binding to an antigen on the standard RBCs and the binding Coombs reagent in order to agglutinate.
In addition to the Rh system, what are some other clinically significant RBC antigens?	Kidd (Causes severe acute hemolytic transfusion reactions), Duffy and Kell
What tests are performed on donated blood to screen for human immunodeficiency virus (HIV) contamination?	Standard tests for anti HIV-1 and HIV-2 antibodies. HIV-1 p24 antigen (by ELISA) and HIV nucleic acid testing are also used specifically to detect very early infection.
What is used as an anticoagulant in blood components?	Citrate
How does the anticoagulant work?	It binds calcium ions, making them unavailable to be used as cofactors in the coagulation cascade.
What are the available blood components for transfusion?	Red blood cells (RBCs) fresh frozen plasma (FFP), platelets (PLT). cryoprecipitate (cryo from FFP)
How many units of whole blood does the average adult have in his/her body?	8 to 10 units.
On average, giving 1 unit of packed RBCs should raise the hemoglobin level by how much?	I g/dL
What type of RBCs should be given to patients who have had previous problems with febrile reactions to blood products, or who will be chronically transfused?	Leukocyte-reduced RBCs since they decrease the risk of human leukocyte antigen (HLA) autoimmunization and the risk of transfusion reactions.
What should be used as an intravascular volume expander?	Albumin, crystalloid or colloid; not FFP.
When might you give a patient platelets?	Prophylactic use for extremely low platelet counts (<10,000/uL) prior to surgery for low platelet counts (<50,000/uL); to aid coagulation in actively bleeding patients.
What is the usual dose of platelets?	1 unit in adults, or 10 mL/kg in pediatrics
What are apheresis platelets?	Platelets collected from a single donor during an apheresis procedure
What does cryoprecipitate contain?	Factor 9, factor 8, fibrinogen and von Willebrand factor.
What is the most common metabolic side effect of massive blood transfusion?	Alkalosis due to the citrate anticoagulant converting to bicarbonate in the liver.
What correlates to the severity of a febrile nonhemolytic transfusion reaction?	The number of leukocytes present in the blood component.
What is the risk of FFP transfusion?	Allergic/anaphylactic reactions
What causes these allergic reactions?	The patient has IgE antibodies against plasma proteins in the transfused blood
What type of patients will have anaphylactic reactions?	Patients who are IgA deficient and have preformed IgA antibodies
What can be done to prevent anaphylactic reactions in these individuals?	Use washed RBCs and platelets or use plasma from other IgA deficient patients.
What causes TRALI (transfusion-related acute lung injury)?	The donor's antileukocyte antibodies react with the recipient's leukocytes.
What characterizes TRALI clinically?	Pulmonary edema, fever, tachypnea, cyanosis
A patient reports severe nausea and dizziness within an hour of eating shrimp. What type of hypersensitivity reaction is this?	Type 1 hypersensitivity
A 4 year old child has allergic rhinitis, eczema (atopic dermatitis) and asthma. What is the hypersensitivity type?	Type 1 hypersensitivity
A woman is Rh- and pregnant with her second Rh+ child. If she does not receive anti-Rh immunoglobulin during either pregnancy, what will likely happen?	Erythroblastosis fetalis, or hemolytic disease of the newborn, will result since the mother will likely to have anti-Rh antibodies in her bloodstream, from the first pregnancy, that will cause hemolysis of the second fetus' RBCs.
A newborn baby shows signs of anemia and jaundice within the first 24 hours of life. What might he have?	Hemolytic disease of the newborn (due to Rh factor incompatibility or ABO blood group incompatibility between mother and infant)
A woman starts to feel exhausted and light headed a week after beginning a course of penicillin. What is this?	Autoimmune hemolytic anemia, which is a type 2 hypersensitivity reaction to a drug (the body forms antibodies to the drug, the antibody bind the drug on the RBCs, resulting in hemolysis)
A patient develops an itchy, raised, red rash 2 to 3 days after using a new brand of laundry detergent. What is this?	Contact dermatitis, which is a type 4 hypersensitivity reaction
A patient begins receiving a blood transfusion. He develops fever, chills, hypotension, and DIC. What happened?	Acute hemolytic transfusion reaction. The patient received RBCs with an antigen to which he had previously formed alloantibodies, such as ABO antigens or Kidd antigen.
What is an autograft?	Tissue implanted from self (donor and recipient are the same person)
What is an allograft?	Tissue implanted from genetically different donor of the same species as the recipient
What is a xenograft?	Tissue implanted from donor of a different species (eg porcine heart valves in humans)
What is a syngeneic graft?	Transplant between genetically identical indiviuals, eg bone marrow transplant between identical twins.
What antigen labeling system is most important for predicting transplant rejection?	HLA system (especially class 1, DR/DQ)
Name the four types of transplant rejections:	1. Hyperacute (minutes to hours) 2. Acute humoral (within first few months) 3. Acute cellular (within first few months) 4. Chronic (months to years and episodic)
What is the mechanism for hyperacute rejection?	Humoral-there is a preformed cytotoxic antibody to the donor antigen, usually at the level of the vascular endothelium
What histological changes characterize hyperacute transplant rejection?	Fibrinoid necrosis and thrombosis.
What is the mechanism of acute vascular rejection?	Humoral-antibodies to the donor antigen develop over time
What histologic changes characterize acute humoral/vascular rejection?	Arteritis, necrosis, thrombosis, and neutrophilic infiltration.
What histologic changes characterize acute cellular rejection?	Lymphocytes/mononuclear cell infiltration; interstitial and tubular inflammation
What is the mechanism of acute vascular rejection?	Humoral-antibodies to the donor antigen develop over time.
What histologic changes characterize acute humoral/vascular rejection?	Arteritis, necrosis, thrombosis, and neutrophillic infiltration.
What is the mechanism of acute cellular rejection?	Cell-mediated-the recipient's CD4+ and CD8+ lymphocytes attack donor cells.
What histologic changes characterize acute cellular rejection?	Lymphocytes/mononuclear cell infiltration, interstitial and tubular inflammation.
What causes chronic rejection?	Any disturbance in the ability of the host and graft to tolerate one another.
What histologic changes characterize chronic rejection?	Vascular changes, especially intimal hyperplasia and fibrosis.
Describe GVHD	The donor's lymphocytes in the graft immunologically attack the recipient's cell (outside the graft) because the graft lymphocytes recognize the recipient's cells as "non-self"
What characterizes GVHD clinically?	Skin rash, jaundice, and diarrhea
What can be done to attempt to prevent GVHD?	Irradiated the donor cells to eliminate leukocytes
If a person is deficient in polymorphonuclear neutrophils, (PMNs), what types of infections are they most susceptible to?	Infections caused by Staphylococcus, Aspergillus, Candida and gram-negative bacteria
Deficiency in T cells makes you susceptible to what types of infections	Mycobacteria, fungi, parasites, viruses
Deficiency in antibodies makes you susceptible to what types of infections?	Encapsulated organisms and viruses.
Deficiencies in complement make you susceptible to what types of infections?	Neisseria, especially meningococcus.
What are the classic features of a granuloma?	A collection of epitheloid histiocytes with scattered multinucleated giant cells. The granuloma may or may not contain necrosis.
Give examples of granulomatous diseases	Tuberculosis, fungal infections, leprosy, cat scratch disease (Bartonella), sarcoidosis, Wegner, syphilis, Crohn disease.
What HLA allele is associated with ankylosing spondylitis?	B27
Which HLA allele is associated with postgonococcal arthritis?	B27
What are some examples of type IV hypersensitivity reactions?	PPD skin test, contact dermatitis, type I diabetes mellitus, Guillain Barre syndrome, multiple sclerosis
What is the classic example of a delayed type IV reaction?	A reactive purified protein derivative (PPD) tuberculin skin test will be positive within 48 to 72 hours.
What is special about type IV reactions?	This is the only hypersensitivity reaction that does not involve antibodies.
What is the mechanism of type IV reaction?	Activated T lymphocyte activate macrophage and secrete cytokines causing T cell mediated cytotoxicity.
What HLA allele is associated with acute anterior uveitis?	B27
Give two examples of common acquired thrombophilias/hypercoagulable states	Malignancy Antiphospholipid antibodies (anti-cardiolipin antibodies and lupus anticoagulants)
What is thrombotic thrombocytopenic purpura (TTP)?	A condition with widrepsread formation of hyaline thrombi and consumption of platelets that leads to thrombocytopenia and microangiopathic hemolytic anemia.
What might you see microscopically in TTP?S	Schistocytes (Fragmented red blood cells)
What is the most common congenital thrombophilia?	Factor V Leiden-a mutation in Factor V (replacement of arginine with glutamine) conferring resistance to degradation by protein c and therefore leading to increased active factor V and a prothrombotic state. Other less common congenital thrombophilias include: prothrombin G20210A mutation, protein C deficiency, protein S deficiency and antithrombin deficiency.
What causes Bernard-Soulier disease?	Mutation in GpIb resulting in a defect in platelet adhesion.
What causes Glanzmann thrombasthenia?	Mutation in Gp2b/3a, again resulting in defective platelet aggregation.
What medication prolongs the PT/INR (with a normal PTT)?	Warfarin- the INR is typically monitored closely in patients on warfarin therapy.
Which lab value measures the activity of the extrinsic pathway in of the coagulation cascade?	Prothrombin time (PT) from this measurement a standardized number is calculated and reported as the INR.
Where is vWF stored?	It is stored within Weibel-Palade bodies within the vascular endothelial cells.
Chromosomal translocations	.
CML	t(9;22) bcr-abl fusion
AML-M3 (Acute promyelocytic leukemia)	t (15;17)
Burkitt lymphoma	t (8;14)

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Hematology and Immunology

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