1. MLAB 1415- Hematology Keri Brophy-Martinez
Chapter 7: Leukocytes
Part One

2. Terms
Myelopoiesis
the production and development of myeloid cells in the bone marrow
Also known as granulocytopoiesis

3. Leukocytes
Function
Protect the host from infectious agents or pathogens
Innate=Natural Immune response
1st response to pathogens (nonself)
Always available
Neutrophils, monocytes, and macrophage main players
Adaptive Immune response
Starts in lymphoid tissue
Slow
Long-lasting immunity (memory)
Lymphocytes become “activated”

4. Common Myeloid Progenitor= CMP
Common Lymphoid progenitor= CLP
Common Myeloid Progenitor= CMP

5. Neutrophils

6. Neutrophil Lifespan Three areas Bone marrow Peripheral blood Tissues
Differentiation, proliferation, maturation
Peripheral blood
Circulate for a few hours
Tissues
Work in host defense

7. Regulation Neutrophil production primarily regulated by cytokines
Interleukin-3
Granulocyte -monocyte-colony stimulating factor (GM-CSF)
Granulocyte-colony-stimulating factor (G-CSF)

8. Maturation Changes Nucleoli disappear Chromatin condenses
Nuclear mass indents and segments
Cytoplasm becomes granular & pinkens

9. Seg
Band

10. Maturation of the granulocytic series **Least mature to mature**
Myeloblast
Size: 14-20µm
Cytoplasm
Slight amount/blue
No granules (possible Auer rods to be discussed in another section)
Nucleus
Round/Central or eccentric
Reddish purple
1-3 nucleoli
Fine meshlike/lacy chromatin with no clumping
N:C ratio = 4:1

11. Maturation of the granulocytic series
Promyelocyte (progranulocyte)
Size: µm
Cytoplasm
Increased amount/blue
Fine, azurophilic, nonspecific granules present
Nucleus
Round/Central or eccentric
Reddish-purple
Fine, meshlike/lacy chromatin beginning to clump
1-2 nucleoli
N:C ratio = 3:1

12. Maturation of the granulocytic series
Myelocyte
Last myeloid cell capable of division
Size: 12-18µm
Cytoplasm
Increased, bluish-pink (“dawning of neutrophilia”)
Fine specific granules
Secretory vesicles
Nucleus
Round or oval/eccentric
Reddish-purple
Chromatin loosely clumped
No nucleolus
N:C ratio = 2:1 or 1:1

13. Maturation of the granulocytic series
Metamyelocyte
Also called “meta” or “juvenile”
Size: 10-18µm
Cytoplasm
Moderate amount
Specific granules (neutrophilic, eosinophilic or basophilic)
Tertiary granules
Secretory vesicles
Nucleus
Indented (kidney-bean shaped)
Central or eccentric
Purple
Clumped chromatin
No nucleolus
N:C ratio = 1:1

14. Maturation of the granulocytic series
Band
1st stage found in P.B
Size: 9-15µm
Cytoplasm
Moderate amount
Specific granules (see meta)
Nucleus
Elongated, narrow band (sausage) shape with uniform thickness
Central or eccentric
Clumped, coarsely granular chromatin

15. Maturation of the granulocytic series
Segmented neutrophil
Size: 10-16µm
Cytoplasm
Neutrophil - Granules stain equally with eosin and methylene blue, causing a pinkish appearance
Normal in circulation = %
Nucleus
Neutrophil - purplish-red, clumped granular chromatin, 2-5 distinct nuclear lobes connected by a filament of chromatin

16. Eosinophil
Eosinophil - Granules stain mainly red, due to reaction with eosin in stain
Normal in circulation = 0-5%
Eosinophil - deep blue purple, coarsely granular chromatin, 2 distinct lobes
Eosinophil

17. Basophil
Basophil - Granules stain mainly blue, due to the reaction with methylene blue in stain
Normal in circulation = 0-1%
Mast cell is a tissue basophil
Basophil - deep blue purple, coarsely granular chromatin, 2 nuclear lobes (sometimes obscured by cytoplasmic granules
Basophil

18. Function of the granulocytic cells
Neutrophils
Defense against bacterial infections
Eosinophils
Regulate inflammation
Respond to antigenic stimulation in chronic allergies
Interact with larval stages of some helminthic parasites
Basophils
Histamine in granules plays a role in acute, systemic allergic reactions (sudden release of histamine can cause anaphylactic shock)
Granules also contain heparin

19. Granulocytes: A Final Thought
Why are they called granulocytes?
The granules are lysosomes created by lipids that contain hydrolytic enzymes such as peroxidase, acid phosphatase, lysozyme and specific esterase.

20. References
Harmening, D. M. (2009). Clinical Hematology and Fundamentals of Hemostasis. Philadelphia: F.A Davis.
McKenzie, S. B., & Williams, J. L. (2010). Clinical Laboratory Hematology . Upper Saddle River: Pearson Education, Inc.