MLAB 1415- Hematology

Keri Brophy-Martinez

Chapter 7: LeukocytesPart One

Terms

Myelopoiesis the production and development of

myeloid cells in the bone marrow

Also known as granulocytopoiesis

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”

Common Myeloid Progenitor= CMP

Common Lymphoid progenitor= CLP

Neutrophils

Neutrophil Lifespan

Three areas Bone marrow

Differentiation, proliferation, maturation Peripheral blood

Circulate for a few hours Tissues

Work in host defense

Regulation

Neutrophil production primarily regulated by cytokines Interleukin-3 Granulocyte -monocyte-colony

stimulating factor (GM-CSF) Granulocyte-colony-stimulating factor

(G-CSF)

Maturation Changes

Nucleoli disappear Chromatin condenses Nuclear mass indents and segments Cytoplasm becomes granular &

pinkens

Band

Seg

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

Maturation of the granulocytic series

Promyelocyte (progranulocyte)

Size: 15-21 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

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

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

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

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 = 40 - 80%

Nucleus Neutrophil - purplish-red,

clumped granular chromatin, 2-5 distinct nuclear lobes connected by a filament of chromatin

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

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

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

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.

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.