week 7- WBCs Flashcards
• What non-RBC info is in a CBC?
o WBC info: number of WBCs, WBC differential (WBC populations)
o PLT info: number of platelets, platelet volume (MPV)
• What is non-RBC composition of whole blood? Absolute #?
o Plasma: 46-63% o Formed elements: 0.1% platelets and WBCs o N: 55-70%, 2500-8000 o E: 1-4%, 50-500 o B: 0-2%, 25-100 o L: 20-40%, 1000-4000 o Monocytes: 2-8%, 100-700
• What is basic function of WBCs?
o defense system against infectious foreign invaders and non-infectious challenge. 2 separate events:
o Phagocytosis: Involves granulocytes and monocytes
o Development of a specific immune response: Involves monocytes (macrophages) and lymphocytes
• How do WBCs travel in body?
o vascular system is only a temporary residence
o main function of vasculature with respect to WBCs is to transport to body tissues.
• Where is bone marrow? Function? Types?
o production site for all hematopoiesis
o primarily in hollow parts of long flat bones like the sternum and hips
o red and yellow: Majority of RBCs, WBCs and platelets formed in red marrow.
• What are blood stem cells?
o Pluripotent: pluri = more + potential = power
o Refers to the ability of a cell to become many different types of cells
o 2 types of stem cells in bone marrow:
o Mesenchymal: connective tissue, blood vessels and lymphatic tissue
o Hematopoietic: blood cells: RBCs, WBCs, platelets
• How are WBCs differentiated from each other?
o by nuclear and cytoplasmic characteristics
o granulocytes, agranulocytes
• what are granulocytes
o The granules in eosinophils have affinity for the acid part of the Wright’s stain and they stain orange-pink
o Basophils, for the basic part of the stain, bluish-black.
o Neutrophils, for both acid and basic parts, pinkish-blue (purple)
• What are agranuloctes?
o Monocytes: usually large with a horseshoe shaped nucleus
o Lymphocytes may be small (non-reactive) with a large N:C or large (reactive) with a smaller N:C. The nucleus is usually round (small lymphs) or may be slightly indented (large lymphs).
• What stimulates production/maturation of all the different WBCs?
o All different types of cytokines
• What is the general morphologic maturation scheme of WBC/RBCs?
o First 4, for both WBC and RBC o Cytoplasm: more basophilia -> less o Large nucleus -> smaller o Larger nucleoli -> small -> absent o Large cell size -> smaller o 5th: WBC granulocytes only: o Nucleus large and round -> smaller and segments
• What are the 6 general stages of maturation following commitment of stem cell in bone marrow?
o Myeloblast: non-granular cytoplasm and red nucleus
o Promyelocyte: distinct granules
o Myelocyte: cell division possible through this stage, identified as n/e/b
o Metamyelocyte: slightly indented nucleus
o Band/ stab cell: indentation > ½ distance from farthest nucleus margin
o mature n/e/b: Segmented nucleus
• What precursor cells are not seen in normal blood smear? Seen?
o Not: Myeloblast, promyelocytes, myelocyte, metamyelocyte
o Seen: band cell; mature granulocyte
• What does a WBC count tell you?
o total WBC count and differential are measured in an automated counter
o reflects the circulating pool of myeloid and lymphoid cells
o WBC in each microliter (ml;mm3) is reported
• What are normal and bad WBC levels?
o > 2 yrs: 4500-10,000/mL
o 30,000
• What are low/high WBC counts called?
o High= >11,000; leukocytosis
o Low= <4000; leukopenia
• What causes leukocytosis?
o Infections o Leukemic neoplasia o Other malignancy o Trauma, stress, hemorrhage o Tissue necrosis o Inflammation o Dehydration o Thyroid storm o Steroid drugs o Post Splenectomy
• What causes leukopenia?
o Drug toxicity o Bone marrow depression/failure o Severe infections o Dietary deficiencies o Marrow aplasia o Marrow infiltration o Autoimmune disease o Hypersplenism o Chemotherapy
• Where do mature cells go?
o Normally only mature cells go into peripheral blood
o May also remain in storage in marrow
• What may be reason for increase/decrease in WBC count? How do you tell?
o May be d/t alteration of all WBC cell lines
o More commonly results from alteration of only one type of WBC
o Need differential=absolute values of each type, %
o *most variation in WBC count are due to inc/dec in # neutrophils, since by % they are most numerous
• How do you do a differential WBC count?
o Place one drop of blood onto glass slide, spread the drop & air dry.
o Wright’s Stain: A mixture of Methylene Blue basic dye and Eosin red-orange acidic dye.
o Phosphate buffer applied directly on top of stain, rinse, dry & examine.
o Oil immersion [100x] lens: count 100 WBCs
o This gives the RELATIVE # of each type of WBC, expressed as a percentage of the 100 cells counted.
• What are results of a Wright stain? Cell types?
o Cell structures with acidic groups bind the basic dye & appear blue.
o Cell structures with basic groups bind the acidic dye & appear various shades of pink or red-orange.
o Lymphocytes: scant cytoplasm
o Monocytes: ground glass cytoplasm
o Neutrophils: lavender
o Eosinophils: orange/red
o Basophils: blue/black
• What does a normal wright stained blood smear look like?
o Lots of purple RBCs, a few purple neutrophils with segmented purple nuclei
• What is normal WBC differential in newborn?
o WBC: 6-3000 o PMN: 42-80% o Band: 2% o L: 26-36% o Mono: 3-8% o E: 0-5% o B: 0-2%
• Differential in infant, 1-12 mos?
o WBC: 6-18,000 o PMN: 18-44% o Band: 3% o L: 46-76% o M: 3-8% o E: 0-5% o B: 0-2%
• Differential in child, 1-16 yrs?
o WBC: 5-14,000 o PMN: 37-75% o Band: 3% o L: 25-57% o M: 3-8% o E: 0-5% o B: 0-2%
• Differential in adult?
o WBC: 4-10,000 o PMN: 36-75% o Band: 2% o L: 20-50% o M: 3-8% o E: 0-5% o B: 0-2%
• What is the absolute number of WBC cell types?
o =(Total WBC) x Relative % of each cell type
o Important to determine if pt has a sufficient # cells of a specific type
• Give an example of absolute vs relative WBC counts:
o Adult w/ total WBC= 15,000 (ref: 4500-10,000)
o 30% Ns (ref: 55-70%); 70% Ls
o Abs # Ns: 15,000 x 0.3 = 4500 (ref: 2500-8000)
o NORMAL absolute N count; only RELATIVE neutropenia (NOT absolute neutropenia)
• What can PMNs do? Most common?
o =polymorphonuclear leukocytes
o All are capable of phagocytosis
o Neutrophils most common; primary defense against microbial invasion
• What happens to neutrophils? Purpose? Granules?
o Stored in bone marrow 5-7 days (mature neutrophil reserve).
o Circulate in blood ~7 hrs.
o live in tissue for 2 hrs before they apoptose
o Acute bacterial infection, inflammation, & trauma stimulate neutrophil production leading to increased total WBC count
o Granules contain leukocyte alkaline phosphatase (LAP)
• What are pathologic neutrophil stains?
o Cytoplasm may show vacuoles during active phagocytosis
o Toxic granulation: Dark purple granules in cytoplasm due to severe infections, burn pts.
o Shift to the left: inc Band neutrophils in peripheral circulation: response to bacterial infection
o Nucleus becomes hypersegmented with vitamin B12 or folic acid deficiency
• What is neutrophilic toxic granulation? Hypersegmentation?
o found in severe inflammatory states.
o toxic granules are azurophilic, thought to be due to impaired cytoplasmic maturation in the effort to rapidly generate large numbers of granulocytes.
o Hyper: More that 3 cells (per 100) with 5 lobes or one with 6 lobes is evidence
• What are causes of neutrophilia (increased)?
o Acute infection o Trauma o Physical/emotional stress o Inflammatory disorders o Metabolic disorders o Myelocytic leukemia o Cushing’s syndrome
• What are causes of neutropenia (decrease)?
o Overwhelming bacterial infection o Viral infections o Aplastic anemia o Radiation therapy o Addison’s disease o Chemotherapy o Dietary deficiency
• What proteins do eosinophil granules have? What suppresses them? What can it dx?
o contain 4 proteins help eliminate parasites: peroxidase, major basic protein, eosinophil cationic protein, eosinophil-derived neurotoxin
o Increased cortisol levels suppress eosinophils
o Increased eosinophils in nasal smear aid in diagnosis of allergic rhinitis
• What is eosinophilia? Causes?
o >5% = increase o Parasitic infections o Allergic reactions o Asthma, hay fever o Hodgkin’s Disease o Eosinophil Myalgia Syndrome o Eczema o Leukemia o Autoimmune disease o Ovarian Cancer
• What causes eosinopenia?
o Cushing Syndrome o Endogenous or exogenous cortisol excess o Stress (shock, severe burns, severe infections)
• What do basophils do? Contents?
o Similar to mast cells: degranulate during allergic reactions, releasing histamine, etc.
o Capable of phagocytosis of immune complexes
o Granules contain: heparin, histamine and serotonin
• What are differences b/w mast cells and basophils?
o Site of maturation: connective tissues; bone marrow
o Life span: months; days
o Primary location: tissues; intravascular circulation
o Size: 6-12 um; 5-7 um
o Nucleus: oval/round; segmented
o Granules: smaller/more numerous; larger/fewer
o Peptidoglycans: heparin/chondroitin sulfates; predominately chondroitin sulfates
• What is basophilia? Causes?
o >50/mm3 increase o Myleoproliferative diseases: Polycythemia o Granulocytic leukemia o Chronic Myelocytic Leukemia (CML) o Hodgkin’s Lymphoma
• What is basopenia?
o <20/mm3 = decrease o Acute phase of infection o Hyperthryoidism o Stress reactions o Prolonged steroid therapy
• What are the types of agranulocytes? Where they mature? What they do?
o Lymphocytes (T, B, NK cells) and monocytes
o T cells: mature in thymus; involved in cellular mediated immunity: T-suppressor cells (CD8), T-Helper cells (CD4)
o B cells (CD19, CD20): Mature in bone marrow. Participate in humoral immunity, as plasma cells they produce antibodies.
o NK -Natural killer cells (CD56, CD57)
• What is the precursor of lymphocytes? What are B cells?
o Arise from the fixed tissue reticulum cell in the bone marrow
o Plasma cells B lymphocytes that are committed to active production of antibodies
• What are atypical lymphocytes? Appearance?
o seen in some viral infections, e.g. infectious mononucleosis
o larger, less of round shape, relatively smaller N:C, lighter nucleus
• What is lymphocytosis? Causes?
o >4000/mm3 o Viral infections: CMV, HIV o Some bacterial infections (pertussis,TB) o Lymphocytic leukemia o Multiple myeloma (plasma cell proliferation) o Infectious mononucleosis/EBV o Infectious hepatitis o Hypoadrenalism (Addison’s Disease)
• What is lymphopenia?
o Lupus
o Drug therapies – adrenocorticosteroids, chemotherapy
o Radiation therapy
• What is normal immunophenotyping?
o T cells: 60-95%, 800-2500/ uL o –CD4: 60-75%, 600-1500 o –CD8: 250-30%, 300-1000 o B cells: 4-25%, 100-450 o NK: 4-30%, 75-100 o CD4/CD8: >1
• What are monocytes?
o Arise in bone marrow from a common progenitor cell with the granulocytes
o 3 classic characteristics
o Can be produced rapidly as needed, spend longer time in circulation
o Function as phagocytes, much the same as neutrophils do, engulf bacteria
o Remove necrotic debris from blood
• What is monocytosis? Causes?
o (>500/mm3) increase o Some viral infections: infectious mono=EBV o Chronic bacterial infx: Tuberculosis o Subacute Bacterial Endocarditis SBE o Syphilis o Chronic ulcerative colitis o Parasites, e.g. malaria o Monocytic leukemia
• What is monocytopenia? Causes?
o (<100/mm3) decrease o Prednisone o HIV o Hairy Cell Leukemia o Aplastic Anemia
• What is the general WBC response to infection?
o inc # WBCs released from bone marrow pool
o Increase production from myelocyte stage in bone marrow via cell division
o Immature forms are released from bone marrow
o Band cells are most common = left shift
o Severe infections may see occasional metamyelocyte
• What are the WBC “granulocyte pools”?
o Bone Marrow Pool: BMP
o Circulating Granulocyte Pool: CGP
o Marginal Granulocyte Pool: MGP
• What happens with WBCs in early infection?
o Circulating granulocyte pool (CGP) “marginates” along endothelial lining of blood vessels near infected tissues
o Extravasation of CGP “diapedesis” towards site of infection
o Rapid migration to tissues, in excess of marrow release rate, can result in decreased WBC count in early stages of infection
• What are the actions of PMNs?
o 1) activation, diapedesis, chemotaxis
o 2) opsonization
o 3) attachment, ingestion, killing, digestion
• What happens to BMP in early infx?
o Normal: 4-10 day supply of immature cells: released as needed as they mature.
o Bone marrow responds to demand for increased WBCs: Immature forms seen in circulation indicate dysregulation of release mechanism, OR increased DEMAND
• What is masked neutrophilia?
o With increasing bone marrow output in infx, the total body granulocyte pool (TBGP) increases, but due to continued margination, WBC count may still appear normal or decreased
• What is effect of early, late, and recovery infx on granulocyte pools?
o Early: inc BMP -> CGP -> inc MGP
o Late: inc all 3
o Recovery: all 3 normalize
• What happens to GPs in later infx?
o CGP and MGP finally equilibrate due to increased marrow output
o WBC count increases & left shift appears
o Indication that body is responding effectively
• What is a “left shift”?
o Can be severe or mild
o Many more immature granulocytes, compared to mature
• What happens during infx recovery?
o Marrow output drops
o WBC count decreases & left shift disappears
o WBC count returns to normal
• What is a leukemoid rxn? Assoc with?
o A nonleukemic WBC count greater than 50,000/uL, on a differential count with NO more than 5% metamyelocytes or earlier cells.
o Severe bacterial infections, severe toxic states (burns, necrotic tissue), marrow replacement by tumor, severe hemolytic anemia, severe acute blood loss, juvenile rheumatoid arthritis
• How do you differentiate leukemoid rxn vs. leukemia?
o Neutrophil granules contain leukocyte alkaline phosphatase (LAP)
o CML (chronic myeloid leukemia) LAP low
o Leukemoid reactions LAP high
o Requires special stain: Leukocyte Alkaline Phosphatase stain= “LAP” stain
• What is a leukoerythroblastic rxn? Causes?
o presence of both immature WBCs and nucleated RBCs in the peripheral blood
o Metastatic tumor in marrow – 25-30%
o Leukemia – 20%
o Myeloid metaplasia or polycythemia – 10%
o Severe infection, megaloblastic anemia, severe acute hemorrhage - about 5% each
• What are WBC counts in a bacterial infx?
o WBC: 16000, hi o PMN: 79%, hi o Band: 8%, hi o L: 8% o M: 3% o E: 1% o B: 1%
• What are WBC counts in steroid therapy?
o WBC: 12000, hi o PMN: 79%, hi o Band: 4% o L: 14% o M: 3% o E: 0% o B: 0%
• What are WBC counts in splenectomy?
o WBC: 13000, hi o PMN: 50% o Band: 2% o L: 40% o M: 5% o E: 2% o B: 1%
• What are WBC counts in viral infx?
o WBC: 3500, lo o PMN: 50% o Band: 2% o L: 40% o M: 5% o E: 2% o B: 1%
• What are WBC counts in chemotherapy?
o WBC: <3000, lo o PMN: 65% o Band: 0% o L: 20% o M: 12%, hi o E: 2% o B: 1%
• What are platelets? Where do they come from? Where are they? What do they do?
o Small, round anucleated cells
o primary role in blood clotting, vasoconstriction and vascular integrity,
o secondary role as hormone serotonin carrier
o form aggregates when injury occurs to vascular endothelium to help maintain vascular integrity
o Formed in the bone marrow
o Parent cell is the megakaryocyte= cytoplasmic fragments
o Most are found in the circulating blood where they survive for 7-10 days
o 25% -30% found in the spleen & liver (reservoir)
• What are normal and bad platelet counts?
o Adult/elderly/child: 140,000-400,000/mm3
o Infant: 200,000-475,000
o Newborn: 150,000-300,000
o Critical values: 1,000,000/mm3
• What is terminology for pathologic platelet counts?
o Thrombocytopenia = < 150,000
o Thrombocytosis = > 400,000
o Thrombocythemia = > 1,000,000
• What causes thrombocytosis?
o Malignant disorders, esp CML (malignancy is found in 50% of those with unexpected increased platelet counts)
o Polycythemia vera, PCV
o Acute infections, sepsis
o Post-splenectomy syndrome = no reservoir
o Rheumatoid arthritis and other inflammatory dz
o Iron deficiency anemia
o Primary (Essential) thrombocytosis
• What causes thrombocytopenia?
o Hypersplenism o Hemorrhage o Immune thrombocytopenia o Leukemia (except CML increases) o Myelofibrosis o TTP-Thrombotic thrombocytopenia purpura o ITP-Idiopathic o Aplastic anemia o Graves’ disease o Pre-eclampsia o Inherited disorders o DIC o SLE o Pernicious anemia o Hemolytic anemia o Cancer chemotherapy o Severe infection o Drug reactions
• What are the dangers of thrombocytopenia?
o spontaneous hemorrhage.
o > 40,000 rarely exhibit spontaneous hemorrhage, but prolonged bleeding with surgery is common.
o <20,000: risk of spontaneous hemorrhage is severe; Petechiae and ecchymosis common
• What are dangers of thrombocytosis? Thrombocythemia?
o -osis: As the platelet count increases, the probability of ABN platelet function also increases, danger from thrombosis rises
o –emia: Not uncommon for patient to experience spontaneous bleeding & thrombosis. Aggregation usually abnormal
• What are interfering factors with platelet counts?
o High altitude increases count o Strenuous exercise may increase levels o Decreased levels may occur prior to menses o Estrogens increase levels o Many drugs
• What interfering factors with dec plt ct should always be considered?
o EDTA can cause platelets to form “satellites” around WBCs
o Difficult blood draw -> microclots in EDTA tube
o Both of these falsely decreases platelet count; ask lab to review a peripheral blood smear to check for these phenomena.
• What is platelet satellitism? Clumps?
o Platelets attached to outside of WBCs
o Clumps: due to microclots, just aggregates of platelets
• What is the mean platelet colume (MPV)?
o Normal findings: 7.4-10.4 mm3 (or fl)
o average volume of a population of platelets determined by an automated cell counter
o relationship to platelets is the same as MCV relationship to red cells
o varies with total platelet production
• what happens to MPV in diff types of thrombocytopenia?
o Normally reactive bone marrow: large immature platelets are released in attempt to maintain normal function (e.g., hypersplenism)
o Suppressed BM: the platelets that are released are small (e.g., cancer chemotherapy)
• What are interfering factors for MPV?
o EDTA anticoagulant (the standard for cell count blood samples) can create variation of up to 25% increase in size of platelets
• What can cause increased MPV?
o Valvular heart disease o ITP o Sepsis o Immune thrombocytopenia o Severe hemorrhage o B12/Folate deficiency o Myelocytic leukemia
• What causes decreased MPV?
o Aplastic anemia
o Cancer chemotherapy
o Wiskott-Aldrich syndrome
• Macrocytic/Megaloblastic anemia
o RBC: depressed o Hb: depressed o HT: depressed o MCV: elevated o MCH: elevated o MCHC: normal o RDW: elevated o WBC: normal o Neutrophils: hypersegmented
• Bone Marrow dysfunction Pattern
o RBC: depressed o Hb: depressed o Ht: depressed o MCV: normal o MCH: normal o MCHC: normal o RDW: normal o WBC: depressed o Platelets: depressed o MPV: depressed
• Viral infx, autoimmune, leukemia Pattern
o WBC: elevated o Neutrophils: depressed (relative) o Lymphocytes: elevated o Monocytes: normal o Eosinophils: normal o Basophils: normal
• Allergy pattern
o WBC: normal o Neutrophils: normal o Lymphocytes: normal o Monocytes: normal o Eosinophils: elevated o Basophils: normal
