Morphology of Normal White Blood Cells

Dr Mohamed Iqbal Musani.

Granulocytes

Neutrophil

• PMN-Polymorphonuclear Leucocytes.• 60-70% WBC• Appearance: pink

granules in cytoplasm, nucleus has 3-4 lobes

• Function: Phagocytosis of bacteria

• Azurophilic (1°) granules are "lysosomes of PMNs", occur in all leukocytes

Eosinophil (Eos)

• Bilobed nucleus• 2-4% of WBC• Recruited to sites of

inflammation• Function: Involved in

allergy, parasitic infections

• Contains: eosinophilic granules

• Granules contain: major basic protein

• Terminally differentiated

Azurophilic granuels

Basophil

• Circulating form of mast cells

• Terminally differentiated• <1% WBC• Contains: basophilic

granules• Granules contain:

histamine and heparin• IgE receptors• Involved in allergy

Monocyte/ Macrophage

Monocyte• 3-8% WBC• Circulating form (precursor) of

tissue macrophages• Recruited to sites of

inflammationMacrophages• Phagocytosis, bacterial killing,

antigen presentation• Peritoneal cavity: peritoneal

macrophages• Lung: alveolar macrophages• Spleen: splenic macrophages• Liver: Kupffer cells

lymphocyte

•Appearance: small (same size as RBCs), little visible cytoplasm

•NO specific granules

• 20-25% of WBC

•T cells: CMI (for viral infections)

• B cells: humoral (antibody)

• Natural Killer Cells

Granulocyte Development

• Trends:

• Immature Mature

• Large cell Small cell

• No granules Azurophilic (non-specific) granules Cell-specific granules

• Round nucleus indented nucleus U-shaped multilobed (specific for cell type)

myeloblast

• 15-20 m• large, euchromatic,

spherical nucleus (>3 nucleoli)

• basophilic cytoplasm with no granules

• prominent nucleoli• can be seen in peripheral

blood with certain leukemias

promyelocyte• First recognizable cell in

granulopoiesis– Cannot tell what kind of cell

it will become

• 17-26 um in diameter• Largest cell in series• Large oval nucleus• Muliple nucleoli• Golgi Ghost• Azurophilic (primary)

granules in cytoplasm– Produced only at this stage

nucleoli

Azurophilic granuels

Myelocyte (M1)

• Spherical nucleus– Becomes increasingly

heterochromatic• Prominent Golgi

apparatus– Negative image– Lots of azurophilic

granules• Formation of specific

granules– Emerge from Golgi (cis

face) complex– Characteristic staining

reactions for each line• Last stage that can do

mitosis

Late Myelocyte/ Early Metamyelocyte

Neutraphil myelocyte

Eosinophil myelocyte

golgi

Metamyelocyte (M2)

• First stage that is clearly divided into separate lines

• Few hundred granules present in the cytoplasm

• Specific granules outnumber the azurophlic granules 4:1

• Nucleus – Heterochromatic– Indentation deepens to

form horse-shoe shape

Late neutraphilic metamylocyte

Neutraphilic metamylocytes

Eosinophil metamylocyte

Band Cells (M3)

• Last immature stage in Neutrophilic series

• Sometimes seen in circulation– Particularly during states of

chronic infection

• Nucleus is elongated and of uniform width

• Nucleus constricts – 2-5 lobes are formed– PMNs