Flashcards in Unit 1 Deck (73):
What are the 5 types of white blood cells (leukocytes) in the body?
2. Neutrophils (PMNs)
Contrast leukemia vs. lymphoma
-Leukemia: malignant cells arise from the bone marrow and usually are in the bloodstream
-Lymphoma: "extramedullary" (outside of the bone marrow) collections of malignant lymphoid
Contrast acute vs. chronic leukemia
-Acute means that the clinical course is progressing rapidly without intervention while chronic means that it follows a more indolent course
Contrast lymphoid vs myeloid leukemia
-Lymphoid means arising from the lymphocytic lineage
-Myeloid means arising from one of the other cells lines
What are platelets?
-Platelets are the cellular component of the blood responsible for hemostasis
-Platelets are actually small cell fragments produced from large, polyploid cells in the bone marrow called megakaryocytes
What are the components of a CBC?
1. Hemoglobin: protein component of RBC that carries oxygen
2. Hematocrit: ration of volume of erythrocytes to that of the whole blood
3. Red Blood Cell Count
4. Mean Corpuscular Volume: average volume of RBCs
5. Mean Corpuscular Hemoglobin: weight of hemoglobin of the average red cell (calc)
6. Mean Corpuscular Hemoglobin Concentration: average concentration of Hgb in a given volume of packed red cells (calc)
7. Red Cell Distribution Width: measure of variation in size of the red cells (standard deviation, calc)
5. White Blood Cell Count
6. Absolute Leukocyte Counts (calc)
6. Platelet Count
7. Mean Platelet Volume
Hematocrit = (RBC x MCV) or (RBC Volume/Total volume x 100)
MCV = (Hct/RBC)
MCH = (Hgb/RBC)
MCHC = (Hgb/Hct)
What is a differential? When is it performed? What additional information does it tell you?
-A differential is performed when a physician requests it or when certain specific conditions are met or results are flagged by the analyzer
-Subdivides the leukocytes into counts for monocytes, neutrophils, basophils, etc.
-Detects artifacts that may skew CBC results, morphology of RBCs, WBCs, platelts etc.
-Detects abnormal forced elements such as organisms
-Confirms relative or absolute quantification of WBC populations
-Can be done as a scan (auto diff) or by a tech (manual diff)
-Make a blood film, air dry it, stain it, and examine under microscope
How can you differentiate the different WBCs on a peripheral smear?
1. Neutrophils: nucleus has clumped chromatin divided into 2-5 lobes linked by thin filament
2. Lymphocytes: smaller, not much cytoplasm, round nucleus with dense chromatin
3. Monocytes: largest cells, ample grayish-blue cytoplasm
4. Eosinophils: bi-lobed nucleus, spherical granules are larger, coarse and reddish orange
5. Basophils: nucleus is obscured coarse, purple-blacking granules, least abundant
What transcription factor is most commonly activated in inflammation?
-Transcription factor activated by Toll-Like Receptors and most commonly activates inflammation (chemokines and cytokines)
Cytokines vs Chemokines
-Cytokine: broad category for small proteins that are important in cell signaling. Can signal cells nearby, far away, or act back on the cell they came from
-Chemokine: a type of cytokine that only acts on nearby responsive cells
-Both are involved in inflammatory response
What is the name of the cell that forms the bridge between the innate and adaptive immune system?
-Rich on ski, in gut, and in lungs = where bad things come in
What do T-cells do?
-T cells look for badly damaged and infected cells by surveying the cell's surface. T cells bind an antigen by means of their surface receptors. An antigen plus MHC marker activates the T cell which allows it to proliferate and have its daughter cells travel the body clearing the infected cells.
-There are 5 types of T cells. They are developed in the bone marrow and mature in the THymus
-Part of adaptive immunity
Describe B-cells and antibodies
-B cells also recognize antigens via surface receptors, become activated and proliferate. However B cells do not need to bind MHC marker and they do not go out and do the work themselves. They send a soluble version of their receptors called antibodies to do the work.
What is a reticulocyte and how is it used in evaluating anemia?
-Reticulocyte: immature red blood cells containing mRNA that are released from the bone marrow and can circulate for about a day before maturing to RBCs
-Normal reticulocyte count is 0.5-2%
-Reticulocyte Index adjusts reticulocyte production by the severity of anemia
-RI = Reticulocyte count x (patient Hgb/Normal Hgb) x (1/stress factor)
-RI less than 2 with anemia is a decreased or inadequate RBC production. RI greater than 3 with anemia means compensatory production.
Describe key characteristics of iron.
-Iron exists in two valence states (ferric = Fe3+ or ferrous = Fe2+, bound to hemoglobin) and activity depends on which state it is in
-In aqueous solution iron forms rust unless bound to chaperon protein
-Iron is more soluble at low pH
-Iron losses are fixed (exfoliation of skin, GI mucosa, menstruation) so iron balance is fixed based on absorption
-Most iron is used in hemoglobin for oxygen transport, also used in myoglobin (muscle oxygen storage), and cellular metabolism
-Types of dietary iron: heme-iron which is animal derived and non-heme iron in some vegetables, cereals, and fruit
-Iron absorption can be depressed by calcium, phosphates, phytates, and hepcidin
Describe the iron cycle
-Iron is absorbed in the small intestine, bound to transferrin which takes it to the bone marrow, then it's bound to a RBC for 120 days, then it is removed from RBC by macrophages in the spleen and stored as ferritin until needed again.
Transferrin vs Ferritin
-Transferrin: serum, transports iron through circulation, binds 2 iron atoms
-Ferritin: intracellular, stores iron, 4500 bound iron atoms
Describe general features and key values for the oxygen dissociation curve
-"30-60, 60-90, 40-75"
-P50: partial pressure of oxygen at which Hgb is 50% saturated = 27 mmHg
What conditions shift the oxygen dissociation curve and in which direction?
-Left: increase in pH, decrease in CO2, decrease in DPG, decrease in temperature
-Right: decrease in pH, increase in CO2, increase in DPG, increase in temperature
Oxygen dissociation curves for myoglobin vs hemoglobin
-Myoglobin shifts the curve to the left and changes it from sigmoidal to hyperbolic
-Myoglobin has much lower P50 of 2.75 mmHg
-Myoglobin is a monomer instead of a tetramer and so it does not have positive cooperativity
-Myoglobin is used in the muscles so want oxygen to move into muscles
What is methemoglobinemia?
-Methemoglobinemia is a type of hemoglobin that carries Fe3+ (ferric iron) instead of Fe2+ and thus cannot carry oxygen well. Causes curve to shift left and P50 to go down.
-Blood is a chocolate brown color in this disease
-Can be caused be an autosomal recessive disease called Congenital Methemoglobinemia (blue at birth, but okay), an autosomal dominant disease called Hemoglobin M (asymptomatic cyanosis), or drugs (treat with methylene blue)
Explain carbon monoxide poisoning
-CO has higher affinity than oxygen for heme
-When CO binds an allosteric change occurs so that the other three hemes download oxygen less
-Shifts curve left
-Symptoms: headache, malaise, nausea, seizures, coma, MI, cherry red not cyanotic appearance.
-Treatment: hyperbaric chamber or 100% oxygen.
How does a pulse oximeter work?
-Pulse oximeter uses photo detector to measure deoxyhemoglobin vs oxyhemoglobin. Deoxyhemoglobin has maximal absorption of 660nm and oxyhemoglobin absorption is 940nm
-Pulse oximeter automatically accounts for tissue depth due to experimental calculations
-Ideally in high 90s or 100
-Has many flaws: probe placement, nail polish, deeply pigmented skin, anemia, doesn't measure CO2, misinterprets abnormal Hbs
Define locations of hemtopoiesis during development
-Yolk Sac (3-7 months)
-Liver (4 months-birth)
-Bone marrow (birth to death)
Stem Cell vs Progenitor Cell vs Precursor
-Stem cell: the most primitive cell type, capable of self-renewal or differentiation/maturation. Two types: Pluripotent (mother of all blood cells, gives rise to both lymphoid and myeloid elements) and Multipotent (mother of all myeloid blood cells, some ability to self-renew or they become progenitor cells)
-Progenitor cell: limited ability to self-renew, irreversible committed to differentiate along one or at most 2 lineages
-Precursor: recognizable, maturing cells, capable of cell division, but cannot self-renew, gives rise to mature functional cells in the peripheral blood, lymphoid organs, and reticuloendothelial system
How can you calculate bone marrow cellularity by age?
Bone marrow cellularity (%) = 100-age of patient
List the major hematopoietic growth factors
1. Erythropoietin (epo)
2. Interleukin -3 (IL-3)
3. Granulocyte colony-stimulating factor (G-CSF)
4. Granulocyte-macrophage colony-stimulating factor (GM-CSF)
5. Macrophage colony-stimulating factor (M-CSF)
-Leukocytes whose nucleus has a smooth outline
-Immature monocytes can become macrophages or lymphocytes which are hard to tell the difference between them so we just call them a "mononuclear infiltrate" meaning both T cells and macrophages
Polymorphonuclear Cells (aka Granulocytes)
-cells whose nucleus is lobulated
-have prominant cytoplasmic granules
-include eosinophills, basophils, mast cells, and neutrophils
Plasma vs Serum
-Plasma: the liquid, cell-free part of blood, that has been treated with anti-coagulants
-Serum: the liquid part of blood after coagulation, therefor devoid of clotting factors such as fibrinogen
the valency of antibody refers to the number of antigenic determinants that an antibody molecule can bind to. The valency of all antibodies is at least two (divalent) and in some instances more (multivalent)
The part of the antibody that actually interacts with the antigen
What are the five classes of immunoglobulins?
-most abundant in blood
-can pass through placenta to fetus
-comes up later than IgM after primary immunization, but levels go higher and last longer
-It takes 2 IgGs to activate complement
-first immuniglobulin made
-Decavalent because is a pentameric shape, but the shape rarely allows more than 2 of its 10 binding sites to interact with epitopes
-Best at complement because has 2 adjacent Fc's to begin cascade
-Large and viscous in solution so cannot make too much of it or it would slow down blood
-Does not move out of blood into tissue very well
-IgM is the only antibody made in the fetus
-made by plasma cells in lymphoid tissues near mucous membranes
-assembled into dimer by addition of Jchain while in plasma cell and then secreted into interstitial space
-IgA is exocytosed still bound to a receptor called the secretory component (SC). SC protects IgA from digestion in the gut
-works as out first line of immunological defense against invading organism
only important role is as a B cell receptor
-its Fc adheres to mast cells and basophils
-triggers these histamine loaded cells and causes immediate hypersensitivity or allergy
-Important for resistance to parasites
What is the quantitative precipitin test?
The quantitave precipitin test: mix the antigen with antibody in different ratios and see how much precipitate is formed. Relative antigen or antibody excess decreases the amount of precipitate because the complexes are smaller and not every molecule may get bound
Precipitation vs Agglutination
-Precipitation: large immune complexes that are formed at or near equivalence tend to become insoluble and fall out of solution, when the antigen is a molecule it is called precipitation
-Agglutination: large immune complexes that are formed at or near equivalence tend to become insoluble and fall out of solution, when the antigen is a cell or cell-sized particle it is called agglutination. More readily detected than precipitation.
What are the three pathways of complement?
Describe the classical pathway of complement
-activated by IgG or IgM with antibody
-Fc portion of antibodies allows binding and activation of C1q. C1q must interact with @ Fcs simultaneously
-C1 activates C4 then C2 which together activate C3, which activates C5-C6-C7-C8-C9.
Describe the alternative pathway of complement
-activated by IgA-antigen complexes
-part of innate immune response
-activated by C3, factor B, properin, and factor D which activates C5 and thus C6-C7-C8-C9
Describe the lectin pathway of complement
-part of innate immunity
-mediated by mannose-binding protein (MBO/MBL) and a lectin
-MBP binds to carbohydrate containing structure that are unique to bacteria
-a component of complement
-put antibodies and complement components on surface of bug like handles so that neutrophil can grab it and eat it
-component of complement
-membrane attack complex is activated by C5
-C8 and C9 poke holes in cell membrane so cell loses ability to regulate osmotic pressure and pops
-component of complement
-C3a, C4a, and C5a all release histamine from mast cells by binding
-causes blood flow to the area and an inflammatory response
-component of complement
-C3a and C5a bring in phagocytes, especially neutrophils to fight the bug
Rank the antibodies by size from largest to smallest
IgM > IgA > IgD > IgE > IgG
Antibody Affinity Maturation
As you have hypermutation you get some B cells that are better and some that are worse. The ones that are better get activated more and are more likely to "stay in the race." Essentially the ones who get activated more stick around that the ones that don't get activated fall out of the race. This leads to the body having better and better immunity to a single antigen.
-refers to the tendency of one antibody to react with more than one antigen. Other epitopes might also fit into the CDR and if they did so detectable, we would say that the antibody cross reacted with those detriments
-Example: you immunize a person with cow pox, the epitope of small pox will also be recognized and the person will be immunized
-an old theory
-antigen told the immune system in some way to make antibodies of appropriate confirmation
-Lamarckian theory because they implied that the outside world instructed the cell to change its genetic information
Clonal Selection Theory
-each cell of the immune system is programmed to make only one antibody, the choice of which antibody the cell makes is random, NOT dependent on outside information and the the entire population PREEXISTS in a normal individual BEFORE contact with the antigens. When a new antigen enters the body, it contact many lymphocytes. When it encounters a lymphocyte whose receptors bind with high affinity, the lymphocyte is activated and makes clones and antibodies. The best fitting clones are SELECTED by the antigen.
-Clonal selection is Darwinian because it has to do with the survival of the fittest and it cuts down on the time for the antibody to mount a response to a pathogen
How is antibody diversity generated?
-Germ line: VDJ combination selection
-Somatic: variable "sloppy" V/J and V/D joining
-Allotype: minor allelic differences in the sequences of immunoglobulins between individuals, determined by allotype of your parents
-Immune system chooses 1 heavy chain from mum or dad and 1 light chain of which their are 4 options (mum kappa, dad kappa, mum lambda, or dad lambda)
-created by sloppiness of V-D and D-J joining
-1) exonucleases chew away a few nucleotides after the DNA is cute, but before the gene segments are joined
-2) enzyme TdT adds nucleotides without a temple, you can't predict the sequence at the joining area
=Lots of diversity produced, but prices is frameshift mutations which results in its death,
Somatic Recombination Model ("Class-Switching")
-Single mature B cells starts by making IgM. Later it gets an external signal to switch to IgG or IgE. In all cases the V domain stays the same, but the C region of the H chain changes
-IgM can go to IgG, but IgG cannot go back to IgM because the mu gene is physically gone (thrown out)
Pre-B cell vs Pre-T Cell
-Pre-B Cell: a B cell with cytoplasmic IgM, but no surface IgM
-Pre-T Cell: in bone marrow, don't hace characteristic surface markers to distinguish them as T cells, but are committed to expressing them in the right environment. Have to go to Thymus to mature to T cell.
Bursa of Fabricus
-Bursa of Fabricus: where precursors from the bone marrow go to finish their development in chickens, burse located by butt.
-The mammalian equivalent is the bone marrow where B cells develop
Describe sequence of developing B cells
1. Pro-B Cell: a cell with cytoplasmic mu chains
2. Pre-B Cell: cytoplasmic IgM
3. Immature B cell: surface IgM, but can only interact with outside world. Body uses this time to see if it self-reacts or not.
4. Mature B Cell: has both IgM and IgD on surface
Describe the primary and secondary antibody response
-During primary B cell responses to antigen IgM is secreted first then usually helper T cells help B cells switch to IgG (or IgA/IgE)
-In response to secondary (booster) immunization, IgM response is the same as in primary, but the IgG response is sooner, faster, higher, and more prolonged because of memory
Discuss how age effects immune repertoire of young and old people.
-People can completely reconstitute their T cell numbers and diversity up to about 40 years old, then diversity becomes increasingly limited, and more and more cells show a "memory" phenotype while fewer are naive. Old people have fewer, but larger clones
-Young people have smaller, but more, clones
-Old people make a good response to antigens they saw in their youth, but fail to respond to new antigens
Possible treatments for sickle cell anemia
-Folic acid: could be used in response to developmental delays caused by anemia
-Penicillin: Sepsis (overwhelming blood infection) due to spleen death is a common cause of death for infants and young children with sickle cell disease, is significantly reduced by the use of prophylactic penicillin and prompt treatment of fever with additional antibiotic therapy.
-Bone marrow transplantation: transplantation done with HLA-matched full sibling unaffected by sickle cell disease with a greater than 90% disease free survival. Only 20% of eligible patients have such a donor available.
-Hydroxyurea therapy: oral chemotherapy agent that induces production of HbF which interferes with sickle hemoglobin polymerization. Improves anemia, reduces frequency of acute pain crises and reduces mortality.
-Transfusion therapy: most people don’t require transfusions. But, if there is worsening anemia, transfusion of RBCs may reverse life-threatening process. Transfusion can be simple or exchange (remove pts RBC’s when normal RBCs are given). Transfusions are associated with transmission of infectious agents and antibody formation and iron overload.
Intravascular hemolysis pathway
-Intravascular hemolysis: turnover within the vascular space, red cells undergoing this will release hemoglobin into the circulation which dissociates into dimer alpha/beta which binds to haptoglobin and is removed by liver. If haptoglobin is overwhelmed, hemoglobin will have the iron oxidized to methemoglobin. Dissociation of globin releases metheme which binds albumin or hemopexin and is converted to bilirubin.
Extravascular hemolysis pathway
Extravascular hemolysis: through ingestion and clearance by macrophages of the reiculoendothelial (RE) system. Red cell ingested by macrophage leads to heme separated from globin, iron removed and stored in ferritin and porphyrin ring converted to bilirubin which is released from cell. Bilirubin converted to water-soluble compound with addition of glucuronic acid. After excretion into biliary tract/small bowel, glucuronic acid is removed and bilibuin is converted to urobilinogen (this cycles between gut and liver or is excreted by kidney into urine).
What are the possible defects in hereditary spherocytosis?
=defect in RBC membrane with one of the following components:
3. Band 3
Osmotic Fragility Test
-Osmotic fragility test is a formal laboratory test used in the diagnosis of hereditary spherocytosis. The test measures the in vitro lysis of RBCs suspended in solutions of decreasing osmolarity. Normal RBCs swell in hypotonic solutions and burst when a critical cellular volume is reached. Spherocytes lyse in solutions of higher osmolarity than normal RBCs. Spherocytes are also more sensitive to a decrease in osmolarity. When graphed, compared to normal RBCs, if spherocytes are present, then the curve will be shifted to the left.
Describe the COOMBS test
-Antiglobulin or Coombs tests are used to detect IgG and/or complement on the surface of the cell. The direct antiglobulin test (DAT), also known as the direct Coombs test, evaluates the presence of either IgG or C3d on the surface of the red cell by the addition of Coombs reagent which has antibodies for IgG, C3d and C4d, causing agglutination. If positive will look and see if it is IgG or complement.
-The indirect antiglobulin test (also known as the indirect Coombs test) detects the ability of patient’s serum to bind IgG and/or complement to test (normal) red blood cells. By definition, autoimmune hemolytic anemia should have a positive DAT.