pathology

1. LEUCOCYTES
DR.SUNDARESAN
PATHOLOGY
LOYOLA COLLEGE

2. SPECIFIC LEARNING
OBJECTIVES
 At the end of the class the student must be able to
 Decribe the normal values functions of leucocytes
 Explain the RES (Reticulo endothelial system)

3. WBC
 WBC differ from RBC – Hb and nucleus
 Ratio RBC and WBC – 600:1
 Total leucocyte range – 4000 – 11000 / mm3

4. CLASSIFICATION
WBC
Granulocytes Agranulocytes
Neutrophil Eosinophil Basophil Monocyte Lymphocyte

5. NORMAL VALUES
Total count – adults – 4000 – 11,000 cells/cu.mm.
- at birth 10,000 – 25,000 cells/cu.mm.
Cell Differential
Count
Absolute count
(cells/cu.mm.)
Neutrophil 50 – 70% 2000 – 7000
Eosinophil 1 – 4% 50 – 500
Basophil 0 – 1% 10 – 100
Monocyte 2 – 8% 200 – 800
Lymphocyte 20 – 40% 1500 - 4000

8. GRANULOCYTES
 GRANULOPOIESIS – production and maturation of
granulocytes
 SITE OF FORMATION
 Before birth – mesoderm, liver & spleen
 After birth – red bone marrow
 During development – granulocytes lose their capacity
to divide and attain specific morphological features –
finally develop into functionally competent cells

9. STAGES OF
GRANULOPOIESIS
Haemocytoblast/pluripotent cell/non
Committed stem cell
Committed stem cell
Myeloblast
Promyelocyte
Myelocyte
Metamyelocyte
Matured granulocytes

10. REGULATION OF
GRANULOPOIESIS
 The following factors stimulate the granulopoiesis
 The rate of production mainly depends on the
concentration of these factors
 Granulocyte-macrophage colony stimulating factor
(GM-CSF)
 Granulocyte colony stimulating factor (G-CSF)
 Macrophage colony stimulating factor (M-CSF)

11.  IL-1
 IL-3
 IL-6
 Tumour necrosis factor
 Fibroblasts
 Endothelial cells
 T-lymphocytes

12. FUNCTIONS OF
NEUTROPHILLS
 1.PHAGOCYTOSIS OF BACTERIA
 These are the frontline soldiers
 DIAPEDESIS
 The circulating cells become marginated
 The cells come out by squeezing through the pores of
the capillary wall and
 Enters the tissue

13.  CHEMOTAXIS
 These are attracted to the site of infection by certain
chemicals released from the site of infection
 OPSONISATION
 Once the cells reach the site – neutrophills start
engulfing the bacteria
 Complements and antibodies get attached to the
bacteria

14.  These are called opsonins
 The process is called opsonosation
 Opsonisation facilitates phagocytosis
 Ca++ ion is required for this process
 First the cell membrane of neutrophil becomes
invaginated until the bacterium is completely engulfed

15.  Then, the digestive pouch called phagosome is formed
 This is merged with a lysozome containing hydrolyzing
enzyme and bacterial agents like h2o2,
myeloperoxidase, lysozyme, lactoferrin
 These enzymes kill and digest the bacterium
 A neutrophil can phagocytize 5-20 bacteria

17.  2.phagocytosis of antigen-antibody complexes
 This prevents the harmful reactions that develop due
to antigen-antobody reaction
 3.phagocytosis of dead cells, foreign particles like
carbon particles, sodium urate crystals
 In other words – neutrophills act as a scavengers
 Microphages – phagocitize small particles

18. Applied aspects  Neutrophilia
Physiological Pathological
Exercise
Pregnancy
Parturition
Emotional stress
Acute pyogenic infections
Rheumatic fever
Myocardial infarction

19. ↓ Neutropenia
Physiological Pathological
Rare
Exposure to cold
Typhoid
Paratyphoid
Aplastic anemia
Viral infection -measles

20. ARNETH COUNT
N1 N2
N3
N4
N5

21. EOSINOPHILLS
 These are abundant in the mucosa of GIT, urinary and
respiratory tract
 Their maturation is stimulated by IL-3, IL-5, GM-CSF
 FUNCTIONS
 Have role in clot lysis – they produce prefibrinolysin
 Engulf antigen-antobody complexex – and thereby
prevent more release of vasoactive substanced

22.  It participate in antiallergic role – these contains anti-
inflammatory histaminases and aryl-sulfatase – which
inactivate histamine and SRS-A
 They have a role in detoxification of certain foreighn
proteins
 A basic proteins present in eosinophills – destroys
larval parasites
 Eosinophillic cationic proteins (ECP) – act as
bactericidal and larvicidal

23. Eosinophil
 Eosinophilia ↓ Eosinopenia
Allergic conditions
arasitic infestations
Skin diseases
ACTH therapy
Acute pyogenic infec
Aplastic anemia

24. BASOPHILLS
 It produces heparin – this helps in prevention of
intravascular clotting
 It also contains histamine SRS-A and eosinophillic
chemotactic factor
 So, it may participate in allergic reactions along with
mast cells – like urticaria, rhinitis and anaphylactic
shock
 Participate in lipid metabolism

25. Basophil
 Basophilia ↓ Basophilopenia
Chronic myeloid leukemia
Polycythemia
Rare
Aplastic anemia

26. AGRANULOCYTES
 LYMPHOCYTES – produced from bone marrow and
lymphoid tissue
 MONOCYTES – produced from bone marrow and liver

27. LYMPHOCYTES
B LYMPHOCYTES
 20 %
 Produce antibodies
 Bone marrow
 Humoral immunity
 Bacterial infections
T LYMPHOCYTES
 80%
 Produce chemicals called
cytokines
 Thymus
 Cell mediated
 Viral infections

28. LYMPHOCYTES
B LYMPHOCYTES
 Shorter life span
 Class II MHC present on
membrane
 Have immunoglobulins
 Agammaglobulinaemia
 Multiple myeloma
T LYMPHOCYTES
 Longer life span
 Absent
 Absent
 AIDS
 Various autoimmune
diseases

29. Lymphocyte
 Lymphocytosis ↓ Lymphocytopenia
Chronic infections
Infectious Mononucleosis
Lymphoma
Viral infection
Immunosuppressive therapy
ACTH therapy
Hodgkin’s disease
Bone marrow failure

30. MONOCYTE(BLOOD
MACROPHAGES)
 FUNCTIONS
 These enters the tissue and form the tissue
macrophages and act as scavengers
 Phagocitize several bacteria
 Engulf large particulate matter, dead tissue cells and
senile cells

31.  Monocyte along with other macrophages involved in
phagocytosis and destruction of necrotic material
 Participate in humoral and cellular immunity

32. Monocyte
 Monocytosis ↓ Monocytopenia
Malaria
Kala-azar
Monocytic leukemia
Rare
Bone marrow failure
Aplastic anemia

33. RETICULOENDOTHELIAL SYSTEM
Monocyte macrophage system(MMS)
Mononuclear phagocytic system (MPS)
 Generalised phagocytic system
 Special group of cells scattered in different parts
• Powerful phagocytes
• Stained by supravital stains
 Monocytes – macrophages
 Liver – Kupffer cells
 CNS – Microglia
 Lungs – Alveolar macrophages
 Skin – Langerhans cells
 Bone – Osteoclasts
 Lymph nodes, spleen & bone marrow – Dendritic cells
 Connective tissue – Histiocytes [Fixed & wandering]

34. Functions of RES
 More powerful phagocytic action than Neutrophil
 Engulf larger particle
 Engulf more numbers (100)
 Survive even after ingestion of bacteria
 Ingest & destroy RBC & release bilirubin
 Also destroy dead WBC’s & platelets
 Ingest & process antigen & present it to Lymphocyte(play
a role in Immunity)
 Produce IL-1-activates T cell
CSF-GM-regulates erythropoiesis
 Initiate development of antibody
 Activated by lymphokines of T lymphocytes.Migrate to
area of inflammation & engulf bacteria
 Sites of hemopoiesis during fetal life(spleen & liver)