Dr Q Sedick Haemopoeisis Haemopoeisis starts with a pluripotential stem cell that gives rise to...
Transcript of Dr Q Sedick Haemopoeisis Haemopoeisis starts with a pluripotential stem cell that gives rise to...
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 & monocytes2.Immunocytes:lymphocytes & plasma
cells
Phagocytes & immunocytes serve to protect the body against infection using immunoglobin and complement systems.
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
Neutrophil/monocyte functions1. 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 function3. 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/L1.Bacterial infections, e.g. :
periodontitis2.Inflammation and tissue necrosis, 3.Metabolic disorders4.Neoplasm's5.Acute haemorrhage/ haemolysis6.Drugs e.g. :lithium
Leucocytosis…
7. Haematological malignancies: CML/myeloproliferative disorders/polycythaemia vera/myelofibrosis/AML
8. Treatment with myeloid growth factors
9. Asplenia10.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
Eosinophilia
>0,4 x 10^9/lCauses are as follows:1.Allergy / atopy2.Parasitic disease3.Skin diseases- urticuria4.Drug-induced 5.Asthma & pulmonary syndromes-
association with nasal polyps
Eosinophilia
6. Vasculitidis-polyarteritis nodosa7. Malignancies-metastatic and
haematological8. Chronic eosinophilic leukaemia9. Hypereosinophilic syndrome
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/l1.Chronic bacterial infections2.Protozoan infections3.Collagen vascular disease-SLE4.Lymphoma5.Myelodysplasia
Neutropaenia
<2,5 x 10^9/l1.Infections of the mouth &
throat(bacterial/viral)2.Immune-
SLE,hypersensitivity,anaphylaxis3.Drug-induced4.Congenital - Kostmanns syndrome5.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
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