Belinda Mandrell

1. Belinda Mandrell Belinda is a Pediatric Nurse Practitioner and works in the Nursing Research department at St. Jude. She has over 16 years of experience in pediatric oncology here at St. Jude. She received a BSN and MSN from the University of Maryland. She holds a BS in Public Health and is a PhD candidate at the University of Tennessee. Her research interests are in gene expression profile and genotype comparison in pediatric Hodgkin Disease survivors. Belinda has numerous journal publications and several book chapters on Pediatric Oncology. She has spoken at numerous conferences in the United States and Internationally.

2. Blood Cell Development and Interpretation Belinda Mandrell, PNP

3. Formation of Blood Cells Begins in the Bone Marrow with pluripotential hemopoietic stem cells Depending upon the body needs, the cell will become committed and will develop into a particular cell As these cells differentiate and grow, they are assisted by growth inducer proteins

4. Formation of Blood Cells • Growth inducers and differentiation inducers are extrinsic to the bone marrow • For example: If you have an infection the growth inducers will stimulate the bone marrow to increase white cell production

5. Growth Inducers • Four major growth inducers (proteins) have been described • Interleukin-3: promotes growth and reproduction of virtually all the different types of stem cells • The others induce growth of only specific types of committed stem cells

6. Differentiation Inducers • This is another set of proteins that differentiates the stem cell one or more steps toward a final mature blood cell

8. Function of Red Blood Cells AKA “erythrocytes” • Transport hemoglobin, which carries oxygen from lungs to the tissues of the body • Catalyze the reversible reaction between CO2 and H2O via carbonic anhydrase • Forms HCO3- • Acid-base balance

9. Production of RBC’s • Early gestation made in yolk sac, then in liver (small amount by spleen and lymph nodes)… Last month gestation produced by bone marrow • Marrow of all bones make RBCs until approx. age 5 yrs, beyond childhood greatest production is in the vertebrae, sternum, ribs and ilia

11. Differentiation of RBC’s • CFU-E stimulated to differentiate into proerythroblasts • Proerythroblasts mature and divide into basophil erythroblasts (little hgb, have all organelles) • Basophil erythroblast nuclei condense and endoplasmic reticulum is reabsorbed = reticulocyte • Reticulocytes leave bone marrow, further basophilic material is reabsorbed, nucleus extruded, increased hgb is incorporated = mature erythrocyte (within 1-2 days, only 1% retics in circulation)

12. Differentiation of RBC’s • Endoplasmic reticulum is reabsorbed & nucleus condenses • Reticulocytes still contains small amount of golgi apparatus, mitochondria and nucleus • Nucleus is extruded from the cell, increased hgb content

13. Production of RBC’s • Tissue oxygenation is the most essential regulator of RBC production • Anemia, hypoxemia, circulatory failure, high altitude • Erythropoietin • Hormone (glycoprotein) 90% released by the kidney, likely made by tubular epithelium when PaO2 is low in peritubular capillaries • Response to catecholamine and prostaglandins • Some hepatic production 10%

15. Erythropoetin • Stimulates hematopoetic stem cells to differentiate into proerythroblasts • Induces cells to pass through differentiation and maturation stages more quickly • During times of increase RBC synthesis there will be a greater percentage or reticulocytes in circulation • Marker of bone marrow function

16. Maturation of RBC’s • Vitamin B12 (dependent on dietary intake and intrinsic factor made by parietal cells of the stomach) • Folic Acid (dependent on dietary intake) • Required for formation of DNA • Decreased DNA synthesis = decreased nuclear divisions and reduced cell proliferation / slow reproduction • Cells formed are large with fragile membranes = “macrocytes”

17. Life-Span of RBC’s 90-120 days • Cytoplasmic enzymes metabolize glucose and produce ATP to keep RBC’s viable • Maintains integrity of cell membrane (pliability and transport of ions) • Keeps iron in the ferrous rather than the ferric state (preventing methemoglobin form which can not carry oxygen) • Prevents oxidation of cell proteins • With aging membrane becomes fragile and RBC’s lyse (often in red pulp of the spleen)

18. Destruction of RBC’s • After RBC lysis, hemoglobin is phagocytized by macrophages throughout the body • Liver Kuppfer cells, spleen & marrow • Macrophages release the iron from the hemoglobin and pass it back into the blood to be carried by transferrin (for further production of hgb in marrow erythroblasts or to liver and other organs to be stored as ferritin) • Porphyrin is converted to bilirubin, which is released into blood and then secreted by liver into bile

19. Blood Types • Two antigens (agglutins) occur on the Red Cells and are classified as Type A and Type B • These antigens are inherited so a person may have neither of these antigens, have one, or both.

20. Blood Types • No A or B antigen= Type O • A antigen= Type A • B antigen= Type B • A and B antigens present= Type AB

21. Rh Antigens • Six common Rh antigens but Type D is most prevalent and is more antigenic that the other Rh antigens. Persons with this antigen are Rh Positvie and all others are Rh Negative. • 85% of whites are Rh + • 95% American Black are Rh+ • 100% Africian Black are Rh+

22. Erythroblastosis Fetalis • Mother is Rh- and infant is Rh+ • Mother develops anti-Rh agglutinins that diffuse into the placenta causing agglutination of the fetus’ blood. Red cells hemolyze releasing hemoglobin. Macrophages convert hem into bilirubin • Liver and spleen enlarge producing red blood cells

23. Erythroblastosis Fetalis • Infants die from anemia or have mental impairment from increased bilirubin • Treatment:Exchange transfusion with Rh-blood.

24. Platelets • Formed from precursor megakaryocytes • No nuclei, use mitochondria to form ADP / ATP, life-span 8-12 days / cleared by spleen macrophages • Contain the contractile proteins actin, myosin & thrombosthenin • Secrete enzymes, prostaglandins, hormones and calcium ions • Synthesize fibrin-stabilizing factor protein • Secrete growth factor that encourages vascular endothlium, smooth muscle and fibroblasts to regenerate

25. Characteristic of Platelets Cont ... • Specialized cell membranes • Glycoproteins prevent adherence to normal endothelium of blood vessels … platelets selectively adhere to damaged blood vessels with exposed collagen • Large volume of phospholipids • Activating roles in clot formation

26. Conditions That Cause Excessive Bleeding Liver Disease: All clotting factors are formed in liver Vitamin K deficiency: Vit K is needed for liver formation of prothrombin, factor VII, IX, and X. Vit K is synthesized by bacteria in the GI Tract.

27. Bleeding • Hemophilia: Genetic deficiency of factor VIII or IX • Thrombocytopenia will result in bleeding within small venules or capillaries rather than large vessels

28. Immune System Overview • System of eradicating infectious organisms (and toxic substances) from the body • White Blood Cells • Destroy invading bacteria or virus by phagocytosis • Form antibodies and sensitized lymphocytes which destroy or inactivate invaders

29. White Blood Cells AKA “leukocytes” • Mobile units of the body’s protective system • Formed in bone marrow • granulocytes, monocytes and some lymphocytes • Formed in lymph tissue • Lymphocytes and plasma cells

30. Types of WBC’s • Polymorphonuclear neutrophils • Polymorphonuclear eosinophils • Polymorphonuclear basophils • Monocytes • Lymphocytes • Plasma Cells Granulocytes or “Polys” - have multiple nuclei

31. Normal Concentrations of WBC’s • Neutrophils 50-60% • Eosinophils 2-3% • Basophils 0.5-1% • Monocytes 5-10% • Lymphocytes 20-40%

32. Infant White Blood Cell Counts • Newborns may have total count of 30,000 – 40,000 • Throughout first year of life gradually decreases to adult levels

33. Production of WBC’s • Pluripotential hematopoetic stem cells differentiate into committed stem cells • Committed stem cells further differentiate into RBC’s and WBC lineages • WBC lineages or Colony Forming Units CFU’s • Myelocytic - myeloblasts • Granulocytes & monocytes (formed in bone marrow) • Lymphocytic - lymphoblasts • Lymphocytes & plasma cells (formed in lymph tissue)

35. Differentiation of WBCs

36. Life Span of WBCs Formed and stored until needed Approximately 6 day supply • Granulocytes: • Survive in blood 4-8 hours • Survive in tissue 4-5 days • Monocytes: • Spend 10-20 hours in blood then deposit in tissue = tissue macrophages which survive for months • Lymphocytes stored in lymph tissue / pass in and out of blood • Survive weeks to months

37. Neutrophils & Macrophages • Destroy invading microorganisms via phagocytosis • Enter tissue spaces via diapedesis • Move through tissues spaces by ameboid like motions • Neutrophils are mature WBC’s in circulating blood • Macrophages were circulating blood monocytes that matured after moving into a tissues

38. Chemotaxis of Neutrophils & Macrophages • Chemical substances attract neutrophils and macrophages to a site of injury / inflammation • Bacterial and viral toxins • Cytokines • Complement proteins • Clotting proteins • Associated with increased capillary membrane permeability to facilitate movement of the WBCs from the blood into tissue spaces

39. Phagocytosis • Cellular ingestion of an offending agent • Selection of offending agent: • Rough surface (healthy tissues of the body have smooth cell membranes) • Lack of protein coats (healthy tissues of the body have protein coats that repel phagocytes - dead and foreign materials do not) • Antibodies produced by lymphocytes coat the pathogens and make then susceptible to phagocytosis (Antibody + C3 protein = opsonization)

40. Phagocytosis Continued... • WBC contacts the pathogen and extends pseudopodia to attach and encircle organism • Fuse to enclose organism in a phagocytic vesicle or phagosome within it’s cytoplasm • Lysosomesand other cytoplasmic granules fuse with phagosome and release digestive and bactericidal enzymes into the phagosome = digestive vesicle

41. Phagocytic Chemicals • Proteolytic enzymes - proteases • Break down proteins • Lipases • Break down lipids and phospholipids • Bactericidal agents • Kill bacteria when enzymes fail to digest them • Oxidizing agents from peroxisomes • Superoxide (O2-) • Hydrogen peroxide (H2O2) • hydroxyl ions (OH-) • Myeloperoxidase catalyzes H2O2 + Chloride = hypochlorite

42. Monocyte-Macrophage • Monocytes, fixed tissue macrophages, mobile macrophages and specialized endothelial cells in the bone marrow, spleen and lymph nodes make up the reticuloendothelial system • Fixed tissue macrophages break away and move with strong chemotaxis signal = delay in immediate response to infection (will see increased number of circulating neutrophils in blood stream before increases in monocyte line)

43. Skin & Subcutaneous Tissue Macrophages • Histiocytes • Second line of defense if skin / subcutaneous tissue is exposed to external environment • Histiocytes will divide in-situ in response to local inflammation

44. Brain Macrophages • Microglial cells • Interlaced with neurons in the central nervous system

45. Macrophages of the Lymph Nodes • Microorganisms in tissue do not move through capillary membrane into the blood stream, but can still be filtered by the lymph system • Lymph nodes • Macrophages line the lymph nodes’ sinuses • Organism is destroyed before efferent leads to venous blood

46. Macrophages in the Liver Sinusoids • Kupffer Cells • Interlaced with epithelial cells of the sinusoids • Bacteria in the portal circulation are eradicated before entering the systemic circulation

47. Macrophages of the Spleen and Bone Marrow • Act on microorganisms that enter the blood stream • Macrophages are entrapped by a reticular meshwork • Blood flows through the spleen’s red pulp which contains the macrophages

48. Macrophages of the Lungs • Large number of tissue macrophages are embedded in alveolar walls • Phagocytize pathogens that are inhaled into the lungs • After digestion of a pathogen, alveolar macrophages dump product into lymph system • When a pathogen is difficult to digest, many macrophages group together to form a “giant cell” that digests the pathogen over time (common in TB, noxious dust)

49. Neutrophils & Macrophages and the Inflammatory Response • Inflammation • At site of insult (injury / infection) • Vasodilation (erythema) • Histamine, bradykinin, prostaglandin, nitric oxide • Increased capillary membrane permeability • Edema • Initiation of clotting cascade • Infiltration of WBCs (monocytes and granulocytes)

50. The “Walling-Off” Effect of Inflammation • The tissue spaces and lymphatics are blocked by fibrin clots • Prevents / delays spread of microorganisms, toxins and inflammatory mediators