Haematology and Blood Transfusion Introduction

Blood content, Haematopoiesis, ABO and Rh blood groups, HDFN, Transfusion.

3 substances in blood

• Erythrocytes

• Leukocytes

• Thrombocytes

what is Haematopoiesis

Formation of blood cells

sites of haematopoiesis in fetus

• 0-2 months - yolk sack

• 2-7 months - liver & spleen

• 7-9 months - Bone marrow

sites of haematopoiesis in Infants

Bone marrow

Sites of haematopoiesis in adults

• vertebrae,

• ribs

• sternum

• skull

• sacrum

• proximal ends of femur

• liver

role of stem cells in haematopoietic system

to self renew

and differentiate into progenitors

role of progenitor cells in haematopoietic system

they differentiate into mature, short lived cells

Erythrocytes days in circulation

120

erythrocytes sequestered in?

spleen

erythrocytes shape

biconcave discoid shape

• flexibility and allows for gas exchange

Hemoglobin in fetus

2a and 2y -& HbF

haemaglobin in adults

2a and 2b -& HbA

Erythropoiesis negative feedback

1. stimulus: low blood volume, decreased O2 carried

2. sensor: specialised kidney cells

3. response: erythropoietin released into blood (EPO)

4. Effect: EPO> red bone marrow, preventing cell death, increasing production

neutrophil

60% of wbcs

lobed nucleus

fine granules

6-10hours

non-specific defence against bacterial and fungal infection

pink stain

eosinophils

• 1% of wbcs

• large granules

• bilobed nucleus

• 4-5hours

• parasitic infection defense

• allergies

basophils

• <1% of wbcs

• large granules

• anaphylactic hypersensitivity, inflammatory response

• methylene blue

Monocytes

• 5% of wbcs

• very large

• 10 hours

• matures to phagocytic tissue macrophages

• removes aged rbcs, debris

lymphocytes

• 33% of wbcs

• large round nucleus

• recognition of foreign substances

phagocytosis

1. pseudopodia forms during attachment

2. phagosome forms, bacterium ingested

3. phagosome forms w/ lysosome

4. lysosomal enzyme digests

T-lymphocytes

• developed in thymus after bone marrow

• 40-805 of blood lymphocytes

• cell-mediated immunity

• 2 sub types: T-helper & T-cytotoxic cells

B-lymphocytes

• bone marrow derived

• 10-30% of lymphocytes

• produce antibodies

NK-Lymphocytes

• Natural killer cells

• 5-15% of lymphocytes

• innate immunity

• non specific defense

• targets cancer cells

Thrombocytes

• platelets

• discord, anucleate cells

• granular cytoplasm

• 10-12 days

• atherosclerosis

Plasma

• 60% of total blood volume

• pale, yellow, aqueous, electrolytes and proteins

• 
  

plasma extracellular ions?

Cations - Na²⁺ , (K⁺, Ca²⁺, Fe²⁺, Mg²⁺)

anions - Cl^- , (HCO₃^- , SO4 2-, HPO4 2-)

blood group O antigens

L- fructose added- H antigen

blood group A antigen

N-acetylgalactosamine, H antigen

Blood group B antigen

D-galactose, H antigen

Blood group AB antigen

N-acetylgalactosamine H antigen & D-galactose, H antigen

Blood gp. A plasma antigens

anti B, will agglutinate with anti A and anti AB

Blood gp. B plasma antigens

Anti A, will agglutinate with anti B and anti AB

Blood gp. AB plasma antigens

contains anti A and anti B, will agglutinate with anti A and anti B and anti AB

Blood gp. O plasma antigens

Contains nether, will not agglutinate

IgM

• 10% or Ig serum

• Heavy u chains

• primary IR

• naturally occuring

IgG

• 75% of serum Ig

• heavy y chains

• secondary IR

• needs stimulatory event to occur

Haemolytic Disease of the Foetus & Newborn

1. Mother Rh specific Bcells detect foestus’ different RhD group in its RBCs

2. Rh specific Bcell forms plasma cells and memory cellls

3. Plasma cells form Anti Rh IgM

4. Memory cells release IgG

5. IgG can cross placenta, attcking foetal RBCs

Preventing HDFN?

Rhogam prevents B cell activation and memory cell formation

How to determine blood group?

• plasma w/ known antibodies mixed w/ patient’s rbcs

• > this tells you the antigens present on rbcs

• rbcs w/ known antigens mixed w/ patients plasma

• > confirms antibodies present

Symptoms of wrong transfusions?

fever

pain

circulatory collapse

hemorrhage

death?

Group A can donate to…

A, AB

Group B can donate to…

B, AB

Group AB can donate to…

AB

Group O can donate to…

A, B, AB