the blood - blood typing & transfusion Flashcards
(35 cards)
how long can the different components of blood be stored ?
-red blood cells: up to 35 days (4°C)
-platelets: up to 7 days (25°C)
-plasma: up to 3 years (-30°C)
leucodepletion
removal of WBCs:
-incidence of febrile transfusion reactions
-HLA incompatibility
-transmission of some infections
fresh frozen plasma (FFP)
given to people that are bleeding because they have fun out of one or more clotting factor(s)
-e.g. after severe bleeding
how are patients treated if missing one specific clotting factor ?
often only that factor is replaced by using synthetically made clotting factors
blood transfusion
-essential for treatment of excessive blood loss due to:
=injury or surgery: 27%
=maternity: 6%
=cancer care or anaemia: 67%
-6000 units are needed daily in the UK; annually, 2 mil donations from 1.4 mil donors
qualifications of a safe blood donor
-good health
-unpaid volunteers
-excluding risk factors
=jaundice (hepatitis?)
=travel in malarial areas
=recent tattoo/piercing
=risk factors for HIV or CJD
-screening of blood
-screening of compatibility of donor and recipient
how long must records of blood donations be stored ?
30 years
cell membranes contain many molecules:
-these molecules have lots of different roles (e.g. channels, receptors, identification)
=glycolipids (e.g. ABO Ag)
=proteins (e.g. Rhesus)
=glycoproteins
-antigens (Ag) important to immune system
immune system on non-self & self molecules
-RECOGNISES ‘non-self’ molecules on surface of cells/bacteria/viruses
-IGNORES ‘self’ molecules
ABO group
RBC type
=group A (A antigen)
=group B (B antigen)
=group AB (A & B antigens)
=group O (no antigens)
ABO antigens (Ag’s)
ABO Ag’s are sugar chains attached to the surface of the RBC via the lipid ceramide
gene for the ABO antigens
-ABO blood groups are sugars so there isnt a gene that codes for them
-instead, ABO genes code for glycosyl transferase
-glycosyl transferase is an enzyme that catalases putting the sugar groups together
frequencies of ABO blood group (2018 UK)
O+ : 35%
O- : 13%
A+ : 30%
A- : 8%
B+ : 8%
B- : 2%
AB+ : 2%
AB- : 1%
antibodies (Ab)
-proteins that recognise foreign molecules (Ag) in the body
-trigger an immune response
5 types of antibodies
classified according to their H chain:
-immunoglobin G (IgG)
-immunoglobin M (IgM)
-immunoglobin D (IgD)
-immunoglobin A (IgA)
-immunoglobin E (IgE)
immunoglobin M (IgM)
-made by natural immunity (production of Ab w/o exposure to Ag)
-made out of 5 of the IgGs stuck together
-so IgM is much larger than IgG
antibodies present on the ABO groups
-A: anti-B
-B: anti-A
-AB: none
-O: anti-A and anti-B
ABO antigens and antibodies
-the body makes all of the antibodies (anti-A & anti-B)
-people who are group A (A Ag on surface) will destroy any B-cells that make antibody against self (anti-A)
-but will keep B-cells making antibodies against non-self (anti-B) in their plasma
rhesus (Rh) group
-rhesus is a transmembrane protein on the surface of RBCs
-the rhesus gene is autosomal recessive (most people = rhesus+)
lots of different Rh antigens
- D (most common)
- c
- C
- e
- E
rhesus antigens and antibodies
A+ : A Ag & rhesus D Ag
A- : A Ag
B+ : B Ag & rhesus D Ag
B- : B Ag
O+ : rhesus D Ag
O- : none
AB+ : A Ag, B Ag & rhesus D Ag
AB- : A Ag & B Ag
other blood group antigens
-more than 44 different blood groups
=e.g. Rh, Kell, Fy, Kidd & MN
-not all equally antigenic in transfusion reactions
-ABO strongest
-Rh stronger than other blood groups
=RhD evokes stronger reaction than
the other Rh antigens
natural immunity
IgM antibodies (large) are produced w/o prior exposure to the ABO antigen (anti-A or anti-B)
adaptive immunity
IgG antibodies (small) are produced upon exposure to other RBC Ag’s (e.g. Rhesus)
