Hematopoiesis 06 07

HematopoiesisHematopoiesis

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HematopoiesisHematopoiesisgeneralgeneral

myeloid tissue

lymphoid tissue



myeloid tissuebone marrow

lymphoid tissue



myeloid tissue

bone marrow

erythrocytes

platelets

granulocytes

monocytes

lymphoid tissue



myeloid tissuebone marrow

erythrocytesplateletsgranulocytesmonocytes

lymphoid tissuethymuslymph nodesspleen


Development of Blood CellsDevelopment of Blood Cells

3 wk : formation of blood islands from yolk sac

6 wk : liver becomes hematopoietic organ

6-8 wk : spleen (until 8th month)

12-14wk : bone marrow (life-long)


Development of Blood CellsDevelopment of Blood Cells

3 wk : formation of blood islands from yolk sac

6 wk : liver becomes hematopoietic organ

6-8 wk :spleen (until 8th month)

12-14wk : bone marrow (life-long)

Bone Marrowred marrow

yellow marrow


pluripotent stem cell

lymphoid stem cell

trilineage myeloid stem cell

committed stem cells

Hematopoiesis



Proliferative potential differentiation


Normal Marrow Normal Marrow CompositionComposition

granulocytes & precursors

erythroid precursors

Lymphocytes, monocytes

unidentified or disintegrated cells

60%

20%10%

10%


Normal MarrowNormal Marrow

myeloid to erythroid ratio = 3 : 1

dominant myeloid cellsmyelocytesmetamyelocytesgranulocytes

dominant erythroid cellspolychromatophilic normoblastsorthochromic normoblasts


MyeloblastMyeloblast

cell division: +

~2% of nucleated cells in BM

size: 8-13 m diametercytoplasm: basophilic (many free ribosomes)

no granules

nucleus: undifferentiatedround to ovoidcoarse nucleoli --> sieve-like appearance


PromyelocytePromyelocytecell division: +~5% of nucleated cells in BMsize: 20 m diametercytoplasm: deep blue azurophilic granules

abundant rER, free ribosome numerous mitochondria well developed Golgi

nucleus: round to ovoid occasionally indented prominent nucleoli


MyelocyteMyelocyte

cell division: +

5-20% of nucleated cells in BMcytoplasm: specific granules

decreased in basophilia

nucleus: ovoidirregular shape

disappearing of nucleolidense and compact

chromatin


MetamyelocyteMetamyelocyte

no more cell division

~22% of nucleated cells in BMsize: 10-18 m diameter (slightly larger than mature PMN)

cytoplasm: prominent secondary granules

nucleus: slightly indented, kidney-shapeddense chromatin

no nucleolus


Granulocyte maturationGranulocyte maturationstem cell: <0.1%

myeloblasts: ~2% promyelocytes: ~5%

myelocytes: 5-20%

metamyelocytes: ~22%

granular leukocyteswww.freelivedoctor.com

Lifespan of blood cellsLifespan of blood cells

RBC 120 days

platelet 10 days

granulocytes circ : 9 hours

tissue : days

lymphocyte circ : variable (hours to years)

tissue : weeks to years


Hematopoietic MicroenvironmentHematopoietic Microenvironment

stem cell(s)

stromal cells

growth factors

stimulation


Hematopoietic ResponseHematopoietic Response

hypoxia RBC

infection granulocyte/monocyte

antigen lymphocyte

hemorrhage plateletwww.freelivedoctor.com

Hematopoietic MicroenvironmentHematopoietic Microenvironment

Stromal cells:

fibroblasts

endothelial cells

adipocytes

Growth Factorswww.freelivedoctor.com

Hematopoietic Growth FactorsHematopoietic Growth Factors((SCF, IL-6, GM-CSFSCF, IL-6, GM-CSF, etc.), etc.)

• glycoprotein hormones• secreted by

bone marrow stromal cells

T-cells

monocytes

• regulate division and differentiation of hematopoietic cells

• responsible for basal hematopoiesis and maintaining blood counts in normal ranges

• greatly increased secretion in response to infection


SCF IL-6 GM-CSF

G-CSF

SCF: stem cell factorGM-CSF: granulocyte-macrophage colony-stimulating factorG-CSF: granulocyte colony-stimulating factor

Basal HematopoiesisBasal Hematopoiesis


TNF

IL-3GM-CSFIL-4

IL-1

TNFIL-1

SCFIL-6

GM-CSFG-CSF

Antigen-amplified Antigen-amplified hematopoiesishematopoiesis

Ag

Ag


Hematopoietic Growth FactorsHematopoietic Growth Factors(IL-6, GM-CSF, SCF, etc.)(IL-6, GM-CSF, SCF, etc.)

Bacterial & viral products

monocyteIL-1

TNF

G-CSF

M-CSF

T-cellT-cellGM-CSF

IL-3

FibroblastFibroblast

Endothelial cellEndothelial cell

IL-6

GM-CSF

G-CSF



GROWTH FACTORS

ERYTHROPOIESIS

GRANULOPOIESIS

MEGAKARYOPOIESIS

LYMPHOPOIESIS

ERYTHROPOIESIS

GRANULOPOIESIS

MEGAKARYOPOIESIS

LYMPHOPOIESIS

generation of each specific lineage of mature blood cells is regulated by a specific set of hematopoietic growth factors.


ErythropoiesisErythropoiesis

erythropoietin-independent stage:GM-CSF

SCF

erythropoietin-dependent stage:erythropoietin

marrow stromal cellsmarrow stromal cells

IL-3 (activated T-cells)IL-3 (activated T-cells)

hypoxia(liver, kidney)hypoxia(liver, kidney)


early phase:

Neutropoiesis:

Monopoiesis:

Eosinopoiesis:

Basopoiesis,Mastpoiesis:

GranulopoiesisGranulopoiesis

G-CSF

M-CSF

GM-CSF SCF IL-3

IL-5 IL-3 GM-CSFSCF IL-3


MegakaryopoiesisMegakaryopoiesis

may also play a role

GM-CSFIL-3

SCFIL-6


LymphopoiesisLymphopoiesis

B-cells:initial stage:

later stage:

final proliferation and Ab secretion:

T-cells:

CD8 cells:

CD4 cells:

IL-7 SCFFcg

recIL-4 IL-6

GM-CSF

IL-6

IL-2 Ag

TCR/CD3

CD28


B-cell maturationB-cell maturation


B-cell transformationB-cell transformation


Lymph nodeLymph node


SpleenSpleen


T-cell transformationT-cell transformation


MarkersMarkers

Stem cell: CD34, c-kitrhodamine, Hoechst dyes (pale)

B-cell: CD19, CD20, (CD22), CD79a

T-cell: CD3, CD2, CD5, CD4/CD8

NK-cell: CD16, CD57, CD56


RBC variation and irregularity


anisocytosisanisocytosispoikilocytosispoikilocytosis

anisocytosis (aniso = unequal)

various sizes

poikilocytosis (poikilo = various)

various shapes


elliptocyteselliptocytes

- heredirary elliptocytosis

- iron def. anemia- myelofibrosis with

myeloid metaplasia

- megaloblastic anemia

- sickle cell anemia- normal (<10% of cells)


spherocytesspherocytes

- hereditary spherocytosis

- acquired hemolytic anemia (e.g. AIHA)

- physical or chemical injury

- heat


leptocytesleptocytes(target cells)(target cells)

- liver disease (obstructive jaundice)

- post splenectomy

- hemoglobinopathies (hypochromic anemias)

thalassemia

Hgb C disease

Hgb H diseasebeta thalassemia

relative increase of cell membrane --> “target” formationwww.freelivedoctor.com

schistocytesschistocytes(cell fragments)(cell fragments)

indication of hemolysis

- megaloblastic anemia

- severe burns

- traumatic hemolysis- microangiopathic

hemolytic anemia (helmet cells, triangular cells)

“helmet cell”


acanthocytesacanthocytes(irregular surface spicules)(irregular surface spicules)

irregularly spiculated cells

with bulbous/rounded ends of spicules

- abetalipoproteinemia

- liver disease


echinocytesechinocytes(crenated cells, burr cells)(crenated cells, burr cells)

regularly contracted cells with smooth surface undulation

- uremia

- artifact

- hyperosmolarity- discocyte-echinocyte

transformation (may be associated with reduced ATP of RBCs)


bite cellsbite cells

Removal (“bites”) of membrane by splenic macrophages

- G6PD deficiency


dacrocytesdacrocytes(teardrop cells)(teardrop cells)

- thalassemia

- myelofibrosis


drepanocytesdrepanocytes(sickle cells)(sickle cells)

- sickle cell anemia


rouleauxrouleaux

lined up RBCs in a row

- multiple myeloma


basophilic stipplingbasophilic stippling

irregular basophilic granules

(remnants of RNA)

fine stippling:

•increased production of RBCs (reticulocytosis)

coarse stippling:

•lead poisoning

•impaired Hgb syntheisis

•megaloblastic anemia

•other sever anemiaswww.freelivedoctor.com

sideroblast/siderocytesideroblast/siderocyte

inorganic iron-containing granules (Pappenheimer bodies)

- sideroblastic anemiaabnormally trapped iron in mitochondria forming a ring around nucleus

- post splenectomyring sideroblastsintermediate

sideroblast siderocyte


Howell-Jolly bodyHowell-Jolly body

remnant of nuclear chromatin

single:•megaloblastic anemia•hemolytic anemia•post splenectomy

multiple:•megaloblastic anemia•other abnormal erythropoiesis


Heinz bodiesHeinz bodies

denatured hemoglobin

- G6PD deficiency


leukemoid reactionleukemoid reaction an excessive leukocytic response

leukocytosis of 50 x109/L or higher with shift to the left

or lower counts with considerable numbers

of immature granulocytes quantitative or qualitative changes in

lymphocytes or monocyteswww.freelivedoctor.com

leukemoid reactionleukemoid reaction

neutrophilicneutrophiliceosinophiliceosinophilic

lymphocyticlymphocytic

hemolysishemorrhagemalignancyHodgkin diseasemyelofibrosisTBburnseclampsia

parasite

infectious lymphocytosispertussisTB


leukoerythroblastic reactionleukoerythroblastic reaction

26%

24%

13% 3% 8%

26%

solid tumorslymphomas

myeloprolif dis

acute leukemias benign hematologic conditions

hemolysis

misc.


reactive WBC proliferationsreactive WBC proliferations

leukocytosis(1) increased PMN

i. increased productiona. acute inflammation

- pyogenic bacterial infection

- tissue necrosis

ii. increased release of stored RBCs from BMa. corticosteroids

b. stress

c. endotoxin


increased increased PMNPMN

(1) increased bands (“left shift”)

(2) reactive morphologic changesa. Döhle bodies (aggregates of rough ER)

b. toxic granulations (prominent granules)

c. cytoplasmic vacuoles

(3) increased leukocyte alkaline phosphatase (LAP)

neoplasm (CML) : decreased LAP



leukocytosis(2) increased eosinophils

i. allergies & asthma (type I hypersensitivity reaction)

ii. parasites

iii. drugs

iv. certain skin diseases

v. cancer (adenocarcinoma)



leukocytosis(3) increased monocytes (monocytosis)

i. chronic disordersa. collagen vascular diseases

b. inflammatory bowel disease (IBD)

ii. infectiona. TB



leukocytosis(4) increased lymphocytes (lymphocytosis)

i. viral diseasesa. infectious mononucleosis

ii. chronic inflammatory process


infectious mononucleosisinfectious mononucleosis

- one of causes of lymphocytosis

- a virus-induced diseaseEpstein-Barr virus (EBV)

CMV


(1) EBV invades B-cell via CD21 (CR2)

(2) cytotoxic (CD8) T-cells respond against invaded B-cells

infectious mononucleosisinfectious mononucleosispathophysiologypathophysiology

CD8 T-cells

Atypical lymphocytes (Downey cells)

Monocyte-like appearance (“mononucleosis”)

Peripheral condensation of cytoplasm (“ballerina skirt” appearance)

[enlargement]


(3) heterophil antibody production (heterophil antibody : antibody against other species)

monospot test (Paul-Bunnell reaction)checking for heterophil antibody

CMV-infectious mono: usually heterophil Ab neg



patient population:adolescents and young adults(“kissing disease”)

Sx: “triad” plus one1. Fever2. Sore throat (gray-white memb. on tonsils)3. Lymphadenitis (post auricular nodes)4. Hepatosplenomegaly

self-limited clinical course (resolving in 4-6 wks)



complications:1. hepatic dysfunction (“hepatitis”)

2. splenic rupture

3. rash (if treated with ampicillin)



lymphadenopathylymphadenopathy

a. acute non-specific lymphadenopathytender enlargement of lymph nodes

i. bacterial lymphadenitis• usually focal involvemnt• may see PMNs within lymph nodes

stellate microabscesses = Cat-scratch Dz

ii. viral infection• usually generalized involvement• reactive T-cell immunoblasts (LN & peripheral blood)


lymphadenopathylymphadenopathy

b. chronic non-specific lymphadenopathynon-tender enlargement of lymph nodes

i. follicular hyperplasia (B-cells)1) rheumatoid arthritis2) toxoplasmosis3) early HIV infection

ii. paracortical lymphoid hyperplasia (T-cells)1) viral infection2) drugs (Dilantin)3) systemic lupus erythematosus (SLE)

iii. sinus histiocytosis (macrophages)



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Hematopoiesis 06 07