Dr Pallavi Saxena

ObjectivesIntroductionLeucopoiesisClassificationMorphologyPropertiesFunctionsApplied physiologyRecent advances

Introduction Why leucocytes called white cells??

Gabriel Andral,a French professor of medicine and William Addison, an English country practitioner,reported simultaneously the first description of leucocytes (1843)

Play important role in immunity of the body

Leucopoiesis

DefinitionThe process of development and maturation of white blood cells(leucocytes), is called leucopoiesis.

MYELOID SERIES

HEAMOCYTOBLAST

MYELOID STEM CELL

MYELOBLAST

PROMYELOCYTE

MYELOCYTE

METAMYELOCYTE

BAND FORM

GRANULOCYTE

GRANULOPOIESIS

HEAMOCYTOBLAST

MYELOID STEM CELL

MYELOMONOBLAST

PROMONOCYTE

MONOCYTE (BLOOD)

MACROPHAGE (TISSUES)

FORMATION OF MONOCYTES

MONOCYTE-MACROPHAGE SERIES

HEAMOCYTOBLAST

LYMPHOID STEM CELL

LYMPHOBLAST

PROLYMPHOCYTE

LYMPHOCYTE

PLASMA CELLS

LYMPHOPOIESIS

Regulation of leucopoiesis

Granulopenia or dead granulocytes & monocytes

G-CSFM-CSFGM-CSFInterleukins

Releases

Bone Marrow

GranulocytesMonocytes/macrophages

Stimulate

Increased formationNormal counts inhibit

Normal range of WBC

At birth,in full term infant: 10,000-25,000/µl of bloodInfants upto 1 yr of age:6000-16,000/µl of bloodAdults:4000-11,000/µl of blood

Variations in WBC countTLC > 11,000/µL(Leucocytosis)

Physiological1.Age2.Exercise3.Mental stress4.Pregnancy5.After food intake6.Exp.to low temp.

Pathological1.Acute bacterial infections (pyogenic org.)2.Burns3.Post-operative period4.Tuberculosis5.Glandular fever

TLC < 4000/µL( Leucopenia)1.Infections by non-pyogenic organisms e.g. typhoid fever2.Viral infections, influenza,smallpox,mumps etc3.Protozoal infections4.Starvation & malnutrition5.Aplasia of bone marrow6.Bone marrow depression

Classification

Granulocytes Agranulocytes

Neutrophils

Eosinophils

Basophils

LymphocytesMonocytes

Neutrophils

1. Cell size- 10-14µm2. Nucleus- central or eccentric; 2-6

lobes;deep purplish blue3. Cytoplasm- faint pink4. Granules- fine(pin-point); violet-

pink in color Normal values•Differential:40-75%•Absolute:2000-7500/µl of blood

Eosinophils1. Cell size- 10-14µm2. Nucleus- central or eccentric; 2-3

lobes; purplish blue; “spectacle shaped”

3. Cytoplasm- acidophilic;bright pink in color

4. Granules- large; coarse; crimson red

Normal values•Differential: 1-6%•Absolute:40-440/µl of blood

Basophils1. Cell size- 10-14µm2. Nucleus- central; 2-3 lobes;

purplish blue; overlaid with granules

3. Cytoplasm- basophilic; full of granules

4. Granules- very coarse,deep purple or blue

Normal values•Differential: 0-1%•Absolute: 0-100/µl of blood

Monocyte1. Cell size- 12-20µm2. Nucleus- eccentric or central;

round or oval; pale bluish violet

3. Cytoplasm- abundant; pale blue; clear

Normal values•Differential: 2-10%•Absolute:500-800/µl of blood

Lymphocyte

1. Cell size- LL:12-16µm; SL:7-10µm

2. Nucleus- eccentric; large round nucleus; deep purplish blue

3. Cytoplasm- scanty; light blue color

Normal values•Differential:20-40%•Absolute: 1500-4000/µl of blood

Variation in counts

NeutrophiliaAbsolute count > 10,000/µl of blood•Physiological &

•Pathlogical causes

NeutropeniaAbsolute count< 2500/µl of blood

•Causes??

Life Span Of WBCNot constant. Neutrophils -> 2-5 days Eosinophils -> 7-12 days Basophils -> 12-15 days Monocytes -> 2-5 days Lymphocytes -> ½-1 day

Properties Of WBC’s Diapedesis Ameboid movement Chemotaxis Phagocytosis

Properties of WBCs

FUNCTIONS

Neutrophils

1st line of defense

Granules contain enzymes like Nucleotidases Catalases Antibody like substances -> Defensins

Eosinophils

Defense (specially against parasites )

Role in allergic reactions

Substances present in granules 1. Major basic protein2. Eosinophilic cationic proteins3. Eosinophil peroxidase4. Aryl sulphatase B

Basophils Role in allergic responses Substances present in granules 1. Histamine2. Heparin3. Hyaluronic acid4. Proteases & Myeloperoxidase

Monocytes

1st line of defense Motile & phagocytic Precursors of tissue macrophages

secrete:1. Interleukin 12. Colony stimulating factor3. Platelet activating factor

Lymphocytes

Immunity1.T- Lymphocyte -> Cellular Immunity

2.B- Lymphocyte -> Humoral Immunity

APPLIED PHYSIOLOGY

Variation in counts

NeutrophiliaAbsolute count > 10,000/µl of blood•Physiological &

•Pathlogical causes

NeutropeniaAbsolute count< 2500/µl of blood

•Causes??

Variation in counts

Eosinophilia•Absolute count > 500/µl of blood•Causes??

Eosinopenia•Absolute count < 50/µl of blood

•Causes..??

Basophilia•Absolute count >100/µl of blood

•Causes

Cont….

Basopenia•Decrease in basophil count

•Causes

Lymphocytosis•Absolute count> 4000/µl of blood

•Physiological•Pathological causes

Lymphopenia•Absolute count < 1500/µl of blood

•Causes??

Monocytosis•Count > 800/µl of blood

•Causes??

Monocytopenia•Decrease in monocyte count

•Rare

PATHOLOGICAL VARIATIONS

CYCLIC NEUTROPENIA

Episodes of severe neutropenia usually lasting for 3-6 days

Can be familial & inherited with maturation arrest

Hypereosinophilic syndrome

Criteria of diagnosisPeripheral blood eosinophil >1.5 x 109/LPersistence of counts more than 6 months

Organs involvedHeartLungSkinNeurological

LEUCOCYTES BENIGN DISORDERS Qualitative changes (MORPHOLOGY)

CongenitalPelger-Huet anomaly

Bilobed and occasional unsegmented neutrophils

Autosomal recessive disorder

Chediak-Higashi syndromeAutosomal recessive disorderGiant granules in granulocytes, monocytes and

lymphocytesRecurrent pyogenic infectionsLymphoproliferative syndrome may developTreatment is BMT

Leukemia WBC upto 1,000,00/cu.mm It can be –1. Acute – Lmphoblastic Myeloblastic2. Chronic – Lymphatic Myeloid

RECENT ADVANCES

1.Bone marrow transplantation2.Apheresis & leucocyteapheresis3.Use of special filters & leucocyte depleted

blood4.Flow cytometry5.Alpha interferon

BibliographyEssentials of medical physiology by

K.Sembulingam & Prema Sembulingam

Medical physiology by Guyton & Hall

Medical physiology by Indu Khurana

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