White Blood Cells & Platelets
WBC: -Response to Infection
- Increased # WBCs released from bone marrow -Increase production from myelocyte stage in bone marrow via cell division -Immature forms are released from bone marrow -Band cells are most common = left shift -Severe infections may see occasional metamyelocyte
Differential WBC Count -Calculating the Absolute # of each cell type
-"Absolute" (ABS) Number of cell type: Important for determining if patient has a sufficient # cells of a specific type. ABS # = (Ttl. WBC) X Relative # of each cell type on the Diff. WBC count. NOTE: Convert relative percentage to a decimal prior to performing calculation.
Mean Platelet Volume (MPV) -Decreased Volume * Causes
-APLASTIC ANEMIA -Cancer chemotherapy -Wiskott-Aldrich syndrome
WBCs -Granulocytes 1. Neutrophils/PMNs
-All PMNs capable of phagocytosis -Neutrophils are the most common PMN (polymorphonuclear leukocytes) -are primary defense against microbial invasion -Acute bacterial infection, inflammation, & trauma stimulate neutrophil production -> ^'d total WBC count -Granules contain leukocyte alkaline phosphatase (LAP) -Cytoplasm may show vacuoles during active phagocytosis -Toxic granulation: * Dark purple granules in cytoplasm * mb dt severe infections, burn pts. -Shift to the left: * Increased Band neutrophils in peripheral circulation + response to bacterial infection -Nucleus becomes hypersegmented with vitamin B12 or folic acid deficiency Picture shows: toxic granulation in the small inserted photo and nucleus hypersegmentation in the other 3 PMNs.
WBCs -Agranulocytes 1. Lymphocytes * Development
-Arise from the fixed tissue reticulum cell in the bone marrow -B lymph. mature in BM -T lymph. mature in the thymus -Plasma cells = B lymphocytes that are committed to active production of antibodies -Atypical lymphocytes: are seen in some viral infections, e.g. infectious mononucleosis
WBCs -Monocytes
-Arise in bone marrow from a common progenitor cell with the granulocytes -Can be produced rapidly as needed, spend longer time in circulation -Function as phagocytes, much the same as neutrophils do, engulf bacteria -Remove necrotic debris from blood
WBC: -NRBC effect on WBC count
-Automated cell counters tally Nucleated RBCs as WBCs * NRBC are not hemolyzed by reagents * Need to correct total WBC count * Correction for NRBC always lowers total WBC count Corrected WBC = (Original WBC Count / #NRBC + 100) X 100
WBC: Later Infection
-CGP and MGP finally equilibrate due to increased marrow output -WBC count increases & left shift appears -Indication that body is responding effectively Bone marrow >> CGP > < MGP
WBC: Early Infection
-Circulating granulocyte pool (CGP) "marginates" along endothelial lining of blood vessels near infected tissues -Extravasation of CGP "diapedesis" to Site of infection -Rapid migration rate to tissues, in excess of marrow release rate, can result in decreased WBC count in early stages of infection -Bone marrow responds to demand for ^ WBCs With ^'ing bone marrow output -the total body granulocyte pool (TBGP) ^'s, but due to continued margination, WBC count may still appear normal or decreased, aka "masked neutrophilia" Bone marrow > CGP >>< MGP
Mean Platelet Volume (MPV) -Interfering Factors
-EDTA anticoagulant (the standard for cell count blood samples) can create variation of up to 25% in size of platelets
-Platelet Count
-Formed in the bone marrow -Parent cell is the megakaryocyte -platelets are cytoplasmic fragments -Small, round anucleate cells -Platelets form aggregates when injury occurs to vascular endothelium to help maintain vascular integrity -Most platelets are found in the circulating blood where they survive for 7-10 days -25% -30% found in the spleen & liver (reservoir)
Platelet Count: -Interfering Factors
-High altitude increases count -Platelets have a natural tendency to clump -Strenuous exercise may increase levels -Decreased levels may occur prior to menses -Estrogens increase levels -Many drugs can increase or decrease platelets: Fischbach, p.1225-1227 -EDTA can cause platelets to form "satellites" around WBCs which Falsely decreases Platelet Count. -Difficult blood draw > microclots in EDTA tube > Falsely decreases Platelet Count. -Investigation of decreased Plt count should ALWAYS start with the above - ask lab to review a peripheral blood smear to check for these phenomena. Pictures show: -platelet satellitism due to EDTA in small pic at upper right -platelet clumps due to microclots
WBCs -Granulocytes 3. Basophils
-Known as basophils in the blood & mast cells in the tissues -Capable of phagocytosis of immune complexes -Granules contain: * heparin * histamine * serotonin -Basophils and mast cells degranulate during allergic reactions, releasing histamine, etc.
WBC: Recovery from Infection
-Marrow output drops -WBC count decreases & left shift disappears -WBC count goes to normal Bone marrow > CGP > < MGP
Differential WBC Count -Procedure
-Place one drop of blood S onto glass slide, spread the drop & air dry. -Wright's Stain: A mixture of Methylene Blue basic dye and Eosin red-orange acidic dye. -Phosphate buffer applied directly on top of stain, rinse, dry & examine. -Oil immersion [100x] lens: count 100 WBCs -This gives the RELATIVE # of each type of WBC, expressed as a PERCENTAGE of the 100 cells counted.
Mean Platelet Volume (MPV) -Increased Volume * Causes
-VALVULAR HEART DISEASE -ITP -Sepsis -Immune thrombocytopenia -Severe hemorrhage -B12/FOLATE DEFICIENCY -Myelocytic leukemia
Myeloid Metaplasia
-progressive DZ of the BM where NEOPLASTIC BM STEM CELLS lodge and grow in multiple sites OUTSIDE the BM. -Typically, there is SPLEENIC ENLARGEMENT and a gradual replacement of the BM elements by FIBROSIS, -progressive ANEMIA and VARIABLE changes in WBC and PLT In Myeloid Metaplasia, there's such high demand for blood cells that you get production outside the bone marrow (in spleen & liver)
Mean Platelet Volume (MPV) -In Thrombocytopenia *with normally reactive bone marrow *with a suppressed bone marrow
-with a normally reactive bone marrow: * large immature platelets are released in attempt to maintain normal function (e.g., hypersplenism) with a suppressed bone marrow: * the platelets that are released are small & usu. immature (e.g., cancer chemotherapy)
Granulocyte Pools
1. Bone Marrow Pool: BMP -holds a 4-10 day supply of immature forms. -These can be released as needed as they mature. -Immature forms seen in circulation indicate dysregulation of release mechanism 2. Circulating Granulocyte Pool: CGP -is within the vascular tree, reflected by the WBC count 3. Marginal Granulocyte Pool: MGP -is formed by movement of WBC to vascular walls by being attracted to trophic substances. -Once they are attached to the vessel wall they can move through the wall via diapadesis, and travel to locations where they are needed
WBCs -Wright Stain
Appear BLUE: -NUCLEUS & some cytoplasmic granules -b/c cell structures with acidic groups bind the basic dye & appear blue. Appear PINK: -CYTOPLASM & some cytoplasmic granules -b/c cell structures with basic groups bind the acidic dye & appear various shades of pink or red-orange.
WBCs -Granulocytes 3. Basophils * Basopenia
Basopenia (<20/mm3) = decrease Causes -Acute phase of infection -Hyperthryoidism -Stress reactions -Prolonged steroid therapy
WBCs -Granulocytes 3. Basophils * Basophilia
Basophilia (>50/mm3) = increase Causes -Myleoproliferative diseases: Polycythemia -Granulocytic leukemia -Chronic Myelocytic Leukemia (CML) -Hodgkin's Lymphoma
WBCs -Granulocytes 2. Eosinophils
Cytoplasm contains: -red-orange granules which: * contain 4 proteins help that eliminate parasites: 1. peroxidase 2. major basic protein 3. eosinophil cationic protein 4. eosinophil-derived neurotoxin -Increased cortisol levels suppress eosinophils -Increased eosinophils in nasal smear aid in diagnosis of allergic rhinitis
WBC Decrease -Causes
Decrease in WBCs = LEUKOPENIA -Drug toxicity -Bone marrow failure -Severe infections -Dietary deficiencies -Marrow aplasia -Marrow infiltration -Autoimmune disease -Hypersplenism -Chemotherapy
Thrombocytopenia
Decreased levels = Thrombocytopenia Causes -HYPERSPLENISM -HEMORRHAGE -Immune thrombocytopenia -Leukemia (EXCEPT CML) -Myelofibrosis -TTP-Thrombotic thrombocytopenia purpura -ITP-Idiopathic -Aplastic anemia -Graves' disease -Pre-eclampsia -Inherited disorders -DIC -SLE -Pernicious anemia -Hemolytic anemia -Cancer chemotherapy -Severe infection -Drug reactions
WBCs -Granulocytes 2. Eosinophils * Eosinopenia
Eosinopenia = decrease Causes -Cushing Syndrome (acute adrenal failure) -Endogenous or exogenous cortisol excess -Stress (shock, severe burns, severe infections) -Disappear after corticosteroid administration!!
WBCs -Granulocytes 2. Eosinophils * Eosinophilia
Eosinophilia (>5%) = increase Causes -Parasitic infections -Allergic reactions -Asthma, hay fever -Hodgkin's Disease -Eosinophil Myalgia Syndrome -Eczema -Leukemia -Autoimmune disease -Ovarian Cancer
WBC Count: -Absolute vs. Relative
Example: -Adult with total WBC = 15,000 -WBC Diff.: * 30% neutrophils * 70% lymphocytes Is this patient REALLY neutropenic? -Abs # neutrophils = 15,000 X 0.30 = 4500 -Patient has a normal absolute neutrophil count and only has a relative neutropenia, NOT V absolute neutropenia.
WBC -General Maturation Scheme
General Maturation Scheme in direction of less mature to -> more mature -Cytoplasm: More basophilia -> less basophilia -Large nucleus -> smaller nucleus -Large nucleoli -> Small nucleoli -> then absent -Large cell size -> smaller cell size -For granulocytes: * nucleus large & round -> smaller & segmented
WBC -Granulocyte Maturation
Granulocytes -6 general stages of maturation following commitment of stem cell in bone marrow: 1. Myeloblast: Non-granular cytoplasm and red round nucleus 2. Promyelocyte: blast becomes pro when it develops distinct granules 3. Myelocyte [cell division possible through this stage]: pro becomes cyte when granules differentiate enough to be identified n/e/b 4. Metamyelocyte: has a slightly indented nucleus 5. Band: INDENTATION MORE THAN ½ Width hypothetical round nucleus.isthmus with sides wide enough to reveal two distinct margins with nuclear chromatin visible btw them 6. Segmented cell
Granulocytes -Classified by staining characteristics
Granulocytes 3 types of cells which have different immune functions. Morphologically similar until myelocyte stage. 1. Neutrophil: fine Pinkish/Lavender granules 2. Eosinophil: bright Orange/red granules 3. Basophil: dark Blue/black granules
WBCs -Classification by granule presence & color
Granulocytes -Classified according to staining characteristics of granules. 1. Neutrophils - Lavender 2. Eosinophils - Orange/red 3. Basophils - Blue/black Agranulocytes - lack granules 1. Lymphocytes 2. Monocytes
Thalassemia Major
Hgb A1: 5-20% Hgb A2: 2-3% Hgb F: 65-100% -Homozy= Cooley's anemia -Thal's: Defect in globin chain production -Alpha chains or the beta chains -Mediterranean origin -Evident at 2-3 months of age (when adult hemoglobin production increases) -Severe hemolytic anemia -Death usually occurs in childhood or adolescence -Considerable # NRBC (nucleated RBCs?) -HOWELL-JOLLY bodies -POLYCHROMATOPHILIC RBCs -HYPOCHROMIC-MICROCYTIC -Marked ANISOCYTOSIS -Marked POIKILOCYTOSIS -TARGET CELLs
WBC Increase -Causes
Increase in WBCs= LEUKOCYTOSIS -Infections -Leukemic neoplasia -Other malignancy -Trauma, stress, hemorrhage -Tissue necrosis -Inflammation -Dehydration -Thyroid storm -Steroid drugs
Thrombocytosis -Causes
Increased levels - Thrombocytosis Causes: -MALIGNANT DISORDERS, ESP. CML (malignancy is found in 50% of those with unexpected increased platelet counts) -Polycythemia vera PCV -Acute infections, sepsis -POST-SPLENECTOMY syndrome = no reservoir -Rheumatoid arthritis and other inflammatory dz -Iron deficiency anemia -Primary (Essential) thrombocytosis Picture shows: increased platelet count in CML
WBCs: -Leukemoid Reaction
Leukemoid reaction: -A nonleukemic WBC count greater than 50,000/mm3, or a differential count with NO more than 5% metamyelocytes or earlier cells. Associated with: -Severe bacterial infections -severe toxic states (burns, necrotic tissue) -marrow replacement by tumor -severe hemolytic anemia -severe acute blood loss -juvenile rheumatoid arthritis
WBCs: -Leukoerythroblastic Reaction
Leukoerythroblastic reaction: -Defined by the presence of both immature WBCs and nucleated RBCs in the peripheral blood Causes: -Metastatic tumor in marrow - 25-30% -Leukemia - 20% -Myeloid metaplasia or polycythemia - 10% -Severe infection, megaloblastic anemia, severe acute hemorrhage - about 5% each
WBCs -Agranulocytes
Lymphocytes - three types 1. T cells: Mature in thymus. Involved in cellular mediated immunity: -T-suppressor cells (CD8) -T-helper cells (CD4) 2. B cells (CD19, CD20): Mature in bone marrow. Participate in humoral immunity, produce antiBodies. 3. NK -Natural killer cells (CD56, CD57) Monocytes
WBCs -Agranulocytes 1. Lymphocytes * Lymphocytosis
Lymphocytosis(>4000/mm3) = increase Causes: -Some bacterial infections (pertussis,TB) -Viral infections: CMV, HIV -Lymphocytic leukemia -Multiple myeloma -Infectious mononucleosis/EBV -Infectious hepatitis -Hypoadrenalism (Addison's Disease)
WBCs -Agranulocytes 1. Lymphocytes * Lymphopenia
Lymphopenia (<1000/mm3) = decrease Causes -Non-lymphocytic leukemias -Hodgkin's Disease -Sepsis -Immunodeficiency diseases -SLE -Drug therapies: * adrenocorticosteroids * chemotherapy -Radiation therapy
WBCs -Agranulocytes 1. Monocytes * Monocytopenia
Monocytopenia <100/mm3 = decrease Causes -Prednisone -HIV -Hairy Cell Leukemia -Aplastic Anemia
WBCs -Agranulocytes 1. Monocytes * Monocytosis
Monocytosis (>500/mm3)= increase Causes -Some viral infections, e.g. infectious mono -Chronic bacterial inf. -Tuberculosis -Subacute Bacterial Endocarditis SBE -Syphilis -Chronic ulcerative colitis -Parasites, e.g. malaria -Monocytic leukemia
WBCs -Granulocytes 1. Neutrophils/PMNs *Neutropenia
Neutropenia = Decreased Neutrophils -Overwhelming bacterial infection -Viral infections -Aplastic anemia -Radiation therapy -Addison's disease -Chemotherapy -Dietary deficiency
WBCs: -Differentiating Leukemoid Reaction and Chronic Myelocytic Leukemia (CMP)
Neutrophil granules contain leukocyte alkaline phosphatase (LAP), an enzyme marker used to differentiate CML from leukemoid rxn. -In CML: LAP is low -In Leukemoid reactions: LAP is high Requires special LAP stain Picture caption: -Left: Leukemoid Rxn w/ HIGH LAP -Right: CML w/ LOW LAP
WBCs -Granulocytes 1. Neutrophils/PMNs *Neutrophilia
Neutrophilia= Increased Neutrophils Causes: -Acute infection -Trauma -Physical/emotional stress -Inflammatory disorders -Metabolic disorders -Myelocytic leukemia -Cushing's syndrome
Total WBC Count -Normal & Panic Ranges
Normal -Adult/child > 2 yrs: 5000-10,000 per mm3 -Child < 2 yrs: 6200-17,000 -Newborn: 9000-30,000 Panic LOW: less than 500 per mm3 Panic High: greater than 30,000
-Platelet Count * Normal Range
Normal findings: -Adult/elderly/child: 140,000-400,000/mm3 -Infant: 200,000-475,000 -Newborn: 150,000-300,000 Critical values (Do NOT change b/t labs): <50,000 or >1,000,000/mm3
Mean Platelet Volume (MPV)
Normal findings: 7.4-10.4 mm3 (or fl) -The MPV is the AVERAGE VOLUME of a population of platelets determined by an automated cell counter -MPV relationship to platelets is the same as MCV relationship to red cells -MPV varies with total platelet production
WBC Development
PluriPotent Stem Cell -> 1. Lymphoid Stem Cell -> A. Thymus > T cell B. NK Cell C. B cell -> Plasma Cell 2. Myeloid Stem Cell -> A. Erythrocyte B. Megakaryocyte -> Platelets (blood clotting) C. Monocyte -> Macrophage D. Granulocytes
Hematology: -CBC Indices
RBC info: - # RBCs - Size of RBCs (MCV & RDW) -Hgb -Average Hgb content of RBCs (MCH, MCHC) -hematocrit (% of blood comprised of RBCs). WBC info: - # WBCs - WBC differential (WBC populations) PLT info: - # Platelets - platelet volume (MPV)
WBCs & Platelets -Functions
The overall role of WBCs is -their function as the immune system- protection against infectious processes Platelets have a primary role in -blood clotting -vasoconstriction -vascular integrity -secondary role as hormone serotonin carrier [your gut is your 2nd brain!]
WBCs -How they're classified
WBCs are classified by their: -Defensive function -Nuclear morphology -Site of origin -Presence or absence of specific cytoplasmic granules > special staining technique required to visualize the cells
Picture of Band & Segmented Granulocytes
band on left, segmented on right
Thrombocytopenia
platelet count < 150,000 The danger: -spontaneous hemorrhage. -Counts above 40,000 rarely exhibit spontaneous hemorrage, but prolonged bleeding with surgery is common. -At counts of <20,000 risk of spontaneous hemorrhage is severe. Petechiae (non-blanching) and ecchymosis common at this level
Thrombocythemia
platelet count > 1,000,000 The danger: -Not uncommon for patient to experience spontaneous bleeding & thrombosis. -Aggregation usually abnormal
Thrombocytosis
platelet count > 400,000 The danger: -As the platelet count increases, the probability of abnormal platelet function also increases, danger from thrombosis rises
