1- Production of blood cells
- continuous regulated process of renewal, proliferation, differentiation, and
maturation of all blood cell lineages
Hematopoiesis
2- Also known as “Pluripotential” or “Totipontential”
- Capable of self-renewal and directed differentiation into all required
lineages
• Can turn RBC, Platelet, neutrophil, etc.
Hematopoietic Stem Cell
3Have their respective lifespans and a cell population capable of selfrenewal that sustains the system
Mature Blood Cells
4STAGES OF HEMATOPOIETIC DEVELOPMENTS
Pre-natal (Primitive) Hematopoiesis
-Mesoblastic Phase
-Hepatic Phase
-Medullary (Myeloid) Phase
Adult (Definitive) Hematopoiesis
-Lymphoid Tissue
-Bone Marrow
5- Begins around the 19th day of embryonic development after fertilization,
cells from mesoderm migrates to the yolk sac
➔ Hematopoietic activity is confine to erythropoiesis
➔ Production of cells lasts until the 8th to 12th weeks of gestation (2-3
months)
Mesoblastic Phase
6➔ Embryonic hemoglobin are found up to the 3
rd month of gestation only (blood islands disappear after 3rd month of gestation)
Erythropoiesis
7-As the yolk sac declines in producing blood cells, fetal liver takes charge
that starts from 5th to 7th week of gestation until the 1st or 2nd week of life
- Remains as primary site of production until 6th month of gestation
Hepatic Phase
8- Hematopoietic activity found in the medullary cavity of the bone cavity (red)
and begins at 4th to 5th month of fetal development and continues towards
adulthood
Medullary Phase
9Is the main site of hematopoiesis by the end of 24th week of gestation
o 6 months until you die – remains throughout life
Red Bone Marrow
10Starts to support developing hematopoiesis elements having an
observable myeloid-to-erythroid activity balance (ME Ratio)
Mesenchymal Cells
11M:E Ratio
Normal - 3:1 to 4:1
Infection - 6:1
Leukemia - 25:1
Myeloid Hyperplasia - 20:1
Myeloid Hypoplasia - 3:20
Erythroid Hyperplasia - 1:20
Erythroid Hypoplasia - 5:1
12Growth Factors (Detectable Cytokines)
• Are required for this phase to differentiate blood cells
1. Erythropoietin (EPO)
2. Granulocyte colony stimulating factor (G-CSF)
3. Granulocyte-Macrophage colony-stimulating factor (GM-CSF)
13- Also called as “Adult Hematopoietic Tissue”
- Hematopoietic tissue is in bone marrow or lymphoid tissue containing blood
production
Definitive Hematopoiesis
14In adults, Hematopoietic Tissue is located in the:
o Bone Marrow:
▪ Erythroid
▪ Myeloid
▪ Megakaryocytic
▪ Lymphoid Cells
o Lymph nodes, Spleen, Liver, and Thymus:
▪ Extramedullary Hematopoiesis – can produce
blood cells outside bone marrow (mostly lymphocytes)
15- Found in bone marrow and thymus
- B cells and T cells are derived (lymphocytes)
Primary Lymphoid Tissue
16- Found outside bone marrow
Secondary Lymphoid Tissue
17Lymphoid cells that respond to foreign
antigens
>Lymph nodes
>Mucosa Associated Lymphoid Tissue (MALT) - Waldeyer’s Ring (tonsils)
>Gut Associated Lymphoid Tissue (GALT) - Peyer’s Patches (GItract)
18Hematopoietically active marrow
>Cellular components (blood and precursor cells)
➔ Decreases as we age
Red Marrow
19Hematopoietically inactive marrow
>Fats or adipose tissues (Adipocytes with undifferentiated mesenchymal cells and macrophages)
➔ For support
➔ Increases as we age
Yellow Marrow
20Refers to the process which red marrow is replaced by yellow marrow that
is made up of adipocytes
Retrogression
21Performed to define the ratio of red marrow to yellow marrow
- usually decreases with age
Marrow Cellularity
22Dyes for Staining Active Marrow
1. Iron 52
2. Iron 59
3. Technetium 99m-colloid
23BONE MARROW
-Collection Procedures
Bone Marrow Aspirate - Obtained by bone marrow aspiration
Core Biopsy - Obtained by trephine biopsy
24Bone Marrow Specimen
A. Direct aspirate smear (Bone marrow smear)
B. Anticoagulated aspirate smear - K3 EDTA
C. Crush Smears
D. Imprints, Histologic Section, Marrow Smear Dyes
25BONE MARROW Laboratory Parameters
Iliac Crest - Safest and most accessible for the bone marrow aspirate
Sternum - Main source of blood cell production for adults
26BONE MARROW Collection Sites-
1. Posterior Superior Iliac Crest
2. Anterior Superior Iliac Crest
3. Sternum
4. Anterior Medial Surface of Tibia
5. Spinous process of the vertebrae, ribs, or other red-marrow containing
bones
27Hematopoietic Cells
PHSCs, Progenitor Cells, or Precursor Cells
28Stromal Cells
Endothelial Cells - Lining
Adipocytes - Fats
Macrophages - Phagocytic Cells
Osteoblasts - Bone forming Cells
Osteoclasts - Bone resorbing Cells
Fibroblasts Tissue - Support
29Also called as “Pluripotential Hematopoietic Stem Cells (PHSCs)
• That is further differentiated to become either myeloid and lymphoid
lineages when stimulated by cytokines
Hematopoietic Stem Cells (HSCs)
30- Used for identification and origin of HSCs
- Can be determined by “Immunophenotypic Analysis (Immunophenotyping”
using a flow cytometry
• We use antibodies to detect antigen
Stem Cells Surface Receptors
31Surface Receptors (Markers of Cells)
CD 34 - All hematopoietic stem cells (early progenitor cells)
CD 33, CD 38 - Myeloid cells
CD 71 - Erythroid differentiation
CD 10, CD 38 - B-lymphocytes (CALLA – Common Acute Lymphoblastic Leukemia-associated Antigen)
CD 19, CD 20 - Lymphoid Differentiation (B-cells)
CD 7, CD 5 - T lymphocytes
CD 8 - T-cytotoxic (suppressor cells)
CD 4 - T-helper cells
CD 16, CD 56 - Natural Killer Cells
32Describe the origin of hematopoietic progenitor cells
Stem Cells Theory
33All blood cells are derived from single progenitor stem cells called the pluripotent hematopoietic stem cells (PHSC)
Monophyletic Theory
34Suggests that each blood cells is derived from its own unique stem cells
Polyphyletic Theory
35• Is used to determine the percentage of cells undergoing mitosis in
relation to the total number of cells being produced
• Normal Value = 1-2%
Mitotic Index
• Increased mitotic index implies increased proliferation except in
megaloblastic anemia (prolonged mitosis)
36
- Regulates proliferation, differentiation, and maturation of hematopoietic
precursor cells
Cytokines and Growth Factors
37Cytokines and Growth Factors Examples:
o Interleukins (ILs)
o Lymphokines
o Monokines
o Interferons
o Chemokines
o Colony-stimulating Factors (CSFs)
38Positive Influence
(Allows)
KIT ligand (a.k.a. Stem Cell Factor)
FLT3 Ligand
GM – CSF
Interleukins
39Negative Influence
(Inhibits)
Interferons
Tumor Necrosis Factor-A
Transforming growth Factor-B