Leukocytes

Neutrophil Precursor (Maturation Time: _)

14 days

Stages of Leukocyte Maturation and corresponding cell size

• Myeloblast (14 to 20 um)

• Promyelocyte (16 to 25 um)

• Myelocyte (15 to 18 um)

• Metamyelocyte (14 to 16 um)

• Band/Stab (9 to 15 um)

• Segmented neutrophil (9 to 15 um)

• High N:C ratio (8:1 to 4:1)

• Slightly basophilic cytoplasm, fine nuclear chromatin

• Two to four visible nuclei

Myeloblast

• Nucleus is round to oval and often eccentric

• paranuclear halo or hof is usually seen

• cytoplasm is evenly basophilic and full of primary (azurophilic) granules

Promyelocyte

• Last stage capable of cell division

• Nucleus has more heterochromatin, cytoplasm is more lavender-pink than blue

• Start of synthesis of secondary granules

Myelocyte

• Indented nucleus (kidney-bean shaped or peanut-shaped)

• Cytoplasm contains very little residual RNA (little or no basophilia)

• Start of synthesis of tertiary granules

Metalyelocyte

• Secretory granules/secretory vesicles are formed

• Nucleus is highly clumped

• Indentation exceeds one half the diameter of nucleus

• Youngest stage to appear normally in peripheral circulation

Band/Stab

• Secretory granules continue to be formed

• Presence of 3 to 5 nuclear lobes connected by thread-like filaments

Segmented neutrophil

Components of Primary / Azurophilic / Non-specific granules

• Myeloperoxidase

• Acid beta-glycerophosphatase

• Cathepsins

• Defensins

• Elastase

• Proteinase-3

Components of Secondary / Specific Granules

• Beta2 - microglobulin

• Collagenase

• Gelatinase

• Lactoferrin

• Transcobalamin I

Components of Tertiary Granules

• Beta2-microglobulin

• Collagenase

• Gelatinase

• Lysozyme

• Acetyltransferase

Components of Secretory Granules

• CD11b/CD18

• CD10,CD13,CD14,CD16

• Cytochrome b558

• C1q receptor

• Alkaline phosphatase (only WBC that have alkaline phosphatase activity)

NEUTROPHILS

• once in the blood neutrophils are divided into: (2)

• Half-life in blood: _

• Lifespan: _

• Neutrophilia is an absolute increase in neutrophils: _ in adults and _ in children

• The term _ refers to:

→neutrophilic leukocytosis of _ with a shift to the left

→usually caused by acute/chronic infections, metabolic diseases, inflammation, inflammatory response to malignancy

• once in the blood neutrophils are divided into:

→CIRCULATING NEUTROPHIL POOL (CNP)

→MARGINATED NEUTROPHIL POOL (MNP)

• Half-life in blood: 7 hours

• Lifespan: 2 - 3 days

• Neutrophilia is an absolute increase in neutrophils: 7 × 10^9/L in adults and 8.5 × 10^9/L in children

• The term LEUKEMOID REACTION refers to:

→neutrophilic leukocytosis of >50 × 10^9/L with a shift to the left

→usually caused by acute/chronic infections, metabolic diseases, inflammation, inflammatory response to malignancy

EOSINOPHILS

• development is similar to neutrophil

• first maturation phase can be identified in myelocyte stage with characteristic _

• mature eosinophils have _ nucleus

• Half-life in blood: _

• Lifespan: _

• Counteracts the factors released by _

• Eosinophilia is associated with _

• Specific granules contain (2)

• development is similar to neutrophil

• first maturation phase can be identified in myelocyte stage with characteristic REDDISH-ORANGE SECONDARY GRANULES

• mature eosinophils have BILOBED nucleus

• Half-life in blood: 18 hours

• Lifespan: 2 to 5 days

• Counteracts the factors released by MAST CELLS

• Eosinophilia is associated with PARASITIC INFECTIONS and ALLERGIC REACTIONS

• Specific granules contain (2)

→MAJOR BASIC PROTEIN

→EOSINOPHIL CATIONIC PROTEIN

EOSINOPHILS

• _

→hexagonal bipyramidal crystals composed of _

→present in cytoplasm of eosinophils in prolonged eosinophilic inflammation

• CHARCOTT-LEYDEN CRYSTALS

→hexagonal bipyramidal crystals composed of_LYSOPHOSPHOLIPASE

→present in cytoplasm of eosinophils in prolonged eosinophilic inflammation

BASOPHILS

• partially lobulated nucleus obscured by its blue-black granules

• closely related to _ (involved in immediate hypersensitivity reactions)

• Basophilia is associated with _

• Specific granules contain (3)

• partially lobulated nucleus obscured by its blue-black granules

• closely related to MAST CELLS (involved in immediate hypersensitivity reactions)

• Basophilia is associated with CHRONIC MYELOID LEUKEMIA, ALLERGIC RHINITIS, CHRONIC INFECTIONS, HYPOTHYROIDISM

• Specific granules contain (3)

→HISTAMINE

→HEPARIN SULFATE

→LEUKOTRIENES

LYMPHOCYTES

• Subsets: (3)

• _ N:C ratio with scanty cytoplasm

• Not end-stage cells, still capable of _ when they are stimulated

• Lymphocytosis is usually accompanied by changes in lymphocyte morphology and are associated mainly by _ like (6)

• Subsets: (3)

→T cells - 60 to 70%

→B cells - 10 to 20%

→NK cells - 10 to 15%

• HIGH N:C ratio with scanty cytoplasm

• Not end-stage cells, still capable of MITOSIS when they are stimulated

• Lymphocytosis is usually accompanied by changes in lymphocyte morphology and are associated mainly by VIRAL INFECTIONS like (6)

→INFECTIOUS MONONUCLEIOSIS
→CYTOMEGALOVIRUS

→HEPATITIS

→HIV

→CHICKENPOX

→HERPES

→INFLUENZA

MONOCYTES

• Maturation Stages: (3)

• Appearance on stained smear:

→nucleus may be round, _, _

→cytoplasm is bluish gray with _ granules (_ appearance)

→cytoplasmic and nuclear vacuoles may be present

• functions include phagocytosis, antigen-presenting cells, destruction of senscent RBCs

• MOnocytes remain circulation for approx. _ days

• Monocytosis is associated with _

• Differentiates into _ when they migrate to tissue

• Maturation Stages: (3)

→MONOBLAST

→PROMONOCYTE

→MONOCYTE

• Appearance on stained smear:

→nucleus may be round, HORSE SHOE-SHAPED, KIDNEY-SHAPED

→cytoplasm is bluish gray with FINE AZURE granules (GROUND GLASS appearance)

→cytoplasmic and nuclear vacuoles may be present

• functions include phagocytosis, antigen-presenting cells, destruction of senscent RBCs

• MOnocytes remain circulation for approx. 3 days

• Monocytosis is associated with TUBERCULOSIS, BRUCELLOSIS, LEISHMANIASIS, SBE, MALARIA, AUTOIMMUNE CELLS

• Differentiates into MACROPHAGES when they migrate to tissue