White blood cells

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					Dr Q Sedick

WHITE BLOOD CELLS
Haemopoeisis

 Haemopoeisis starts with a pluripotential
  stem cell that gives rise to separate cell
  lineages.
Leucocytes

May be divided into 2 groups:
1.Phagocytes:granulocytes & monocytes
2.Immunocytes:lymphocytes & plasma cells

Phagocytes & immunocytes serve to protect
  the body against infection using
  immunoglobin and complement systems.
Granulocytes

 Comprised of neutrophils, eosinophils &
  basophils
Neutrophil development
Granulopoeisis

 Many growth factors are involved in the
  maturation process
 Includes IL-1/IL-3/IL-5/IL-6/IL-11/GM-CSF/G-
  CSF/M-CSF
 GF stimulate proliferation and differentiation
  and also affect the function of mature cells on
  which they act
Neutrophils

 Characterized by a dense nucleus consisting
  of 2-5 lobes, pale cytoplasm with an irregular
  outline containing many fine pink granules
Neutrophil granules

 Consists if primary & secondary granules
 Primary : myeloperoxidase/acid
  phosphatase/acid hydrolases
 Secondary: collagenase/lactoferrin &
  lysozyme
  Monocytes




Large oval/indented nucleus, clumped chromatin
  & abundant blue cytoplasm
Neutrophil/monocyte functions

1. Chemotaxis-phagocytes are attracted to
   bacteria by chemotactic substances released
   from the damaged tissues/by complement
   or by leucocyte adhesion molecules
2. Phagocytosis-neutrophils & monocytes have
   FC and C3B receptors which aid in
   opsonization of bacteria
Neutrophil/monocyte function

3. Secretion of growth factors & chemokines-
   aid in pro-inflammatory processes
4. Killing and digestion: via oxygen-dependant
   and oxygen- independent pathways
Eosinophils

 Consists of 2-3 nuclear lobes/ red-staining
  coarser cytoplasmic granules
 Enter inflammatory exudates
 Special role in allergic responses/defense
  against parasites and removal of fibrin
  formed during inflammation
Basophils

 Dark cytoplasmic granules which overly the
  nucleus
 Contain heparin and histamine-released on
  degranulation
 Have IGE attachment sites
 In tissues-mast cells
Defects of leucocytes

NEUTROPHIL LEUCOCYTOSIS:
>7,5 X 10^9/L
1. Bacterial infections, e.g. : periodontitis
2. Inflammation and tissue necrosis,
3. Metabolic disorders
4. Neoplasm's
5. Acute haemorrhage/ haemolysis
6. Drugs e.g. :lithium
Leucocytosis…

7. Haematological malignancies:
   CML/myeloproliferative
   disorders/polycythaemia
   vera/myelofibrosis/AML
8. Treatment with myeloid growth factors
9. Asplenia
10. Rare inherited disorders, e.g.: Down
   syndrome
The leukemoid reaction

 Reactive and excessive leucocytosis
  characterised by the presence of immature
  cells in the peripheral blood
 Seen in severe chronic infections/severe
  haemolysis & metastatic cancer
Severe chronic infections
Malignancy
Eosinophilia

>0,4 x 10^9/l
Causes are as follows:
1. Allergy / atopy
2. Parasitic disease
3. Skin diseases- urticuria
4. Drug-induced
5. Asthma & pulmonary syndromes-
   association with nasal polyps
Urticuria
Eosinophilia

6. Vasculitidis-polyarteritis nodosa
7. Malignancies-metastatic and
   haematological
8. Chronic eosinophilic leukaemia
9. Hypereosinophilic syndrome
Allergy/atopy
Basophilia

 >0,1 x 10^9/l
 Causes include reactive and malignant
 Reactive: infections like small pox & chicken
  pox
 Myeloproliferative disorders-Chronic myeloid
  leukaemia
Monocytosis

>0,8 x 10^9/l
1. Chronic bacterial infections
2. Protozoan infections
3. Collagen vascular disease-SLE
4. Lymphoma
5. Myelodysplasia
Neutropaenia

<2,5 x 10^9/l
1. Infections of the mouth &
   throat(bacterial/viral)
2. Immune-SLE,hypersensitivity,anaphylaxis
3. Drug-induced
4. Congenital - Kostmanns syndrome
5. Bone marrow failure
Lymphocytes

 Lymphocytes are the immunologically
  competent cells that assist the phagocytes in
  defense of the body against infection
 They are involved in processes such as
  antigen specificity and immunological
  memory
Lymphocyte development

 Consists of T and B cells
 B cells:
Derives from the stem cell,matures in the bone
 marrow and circulates in the peripheral blood
 until antigen recognition
On activation B cells secrete immunoglobulin
 and is known as plasma cells
B cells/plasma cells
   T cells

T CELLS:

 Derive from the thymus and differentiates into
  mature T cells during its passage to the bone
  marrow
 Involved in immunological processes such as cell
  mediated cytotoxicity
Lymphocytosis

1. Acute infections-infectious
   mononucleosis/rubella/pertussis/mumps/herpes/CMV/
   HIV
2. Chronic infections-TB/brucellosis/syphillus
3. Chronic lymphocytic leukaemias
4. Acute lymphoblastic leukaemia/NHL
Infectious mononucleosis

				
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posted:9/10/2012
language:English
pages:33