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Blood Types, Transfusions, and Transplants
Blood Types, Transfusions, and Tissue and Organ Transplants
28
Physiology
Graduate
04/12/2012

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Term
What are the different surface antigens for the most common blood groups? What are these antigens composed of molecularly? What is the formal name for the antigens?
Definition
1. A and B; A and B are codominant
2. glycoproteins
3. A and B agglutinogens
Term
How does the O blood type differ from A and B? How do people develop anti-A or anti-B antibodies? What type of Ig antibodies are they? What is the formal name for these antibodies?
Definition
1. O is the lack of surface antigens while A and B are specific surface antigens
2. exposure to A and B antigens in food
3. mostly IgG and IgM; IgM is most involved and it has α-A IgM and α-B IgM
4. anti-A and anti-B agglutinins
Term
What happens if there is a transfusion of A in a person with B blood? O in a person with B? AB in a person with B?
Definition
1. agglutination (attack by the antibodies causing clumping) and either phagocytosis or complement protein activation and lysis
2. it is accepted
3. same as 1
Term
What happens if there is a transfusion of B in a person with A blood? O in a person with A? AB in a person with A?
Definition
1. agglutination (attack by the antibodies causing clumping) and either phagocytosis or complement protein activation and lysis
2. it is accepted
3. same as 1
Term
What happens if there is a transfusion of A in a person with AB blood? B in a person with AB? O in a person with AB?
Definition
1. it is accepted
2. it is accepted
3. it is accepted
Term
What happens if there is a transfusion of A in a person with O blood? B in a person with O? AB in a person with O?
Definition
1. agglutination (attack by the antibodies causing clumping) and either phagocytosis or complement protein activation and lysis
2. same as 1
3. same as 1
Term
Define: hemolysins. List how common the ABO blood types are in order from most common to least.
Definition
1. antibodies that activate the complement protein system in the blood vessels (usually specifically for A or B antigens)
2. O, A, B, AB
Term
What are the different Rhesus factors? What is the most significant factor? How do we represent it (what is its notation)? How does the commonness of Rhesus factor antibodies compare to ABO antibodies?
Definition
1. C, D, E, c, d, e
2. D or d
3. + or -
4. we don't encounter these in food, so Rhesus antibodies are not developed unless there is an exposure to the opposing type of Rhesus factor
Term
Which is the most common Rhesus factor (+ or -)? How common is it?
Definition
1. +
2. 85% among Caucasians, 95% among African-Americans, and 100% among continental Africans
Term
What is haptoglobin? What is its significance?
Definition
1. a protein that can bind to Hb for processing
2. after hemolysis, it is involved in a large portion of the recycling of Hb
Term
What are the different possible products available for transfusion?
Definition
a. whole blood
b. packed RBCs
c. γ-irradiated products
d. CMV-screened products
e. WBC-reduced products
f. washed RBCs
g. platelets
Term
What is the effect of transfusing 1 unit of packed RBCs? What is the benefit of γ-irradiated products? What about CMV screened products? How about washed RBCs?
Definition
1. (about 250-350 mL of RBCs) increase of hematocrit by 1 g/dL in a standard 70 kg individual
2. they are used to prevent graft vs. host rejection
3. they are used when a patient has decreased ability to deal with viruses (pregnant women or transplant recipients)
4. decreases the transfer of plasma proteins
Term
What are some possible general complications that might occur with blood transfusions?
Definition
bacterial infections, viral infections, allergies, graft vs. host rejections, and iron overload
Term
What is the most common bacterial infection of concern with transfusions? Why is it of most concern with tranfusions? Which viruses are of significant concern with tranfusions?
Definition
1. Y. interocolitca
2. the risk of infection increases the longer the blood gets stored
3. HIV, hepatitis C, hepatitis B, HTLV, syphilis, CMV, and prion disease (Crunzfeld-Jacob)
Term
What is erythroblastosis fetalis? Describe it.
Definition
a condition in which a fetus has the opposite Rhesus blood type as the mother (usually the mother is - and the fetus is +); with the first child there is usually no reaction, but the second child with opposing Rhesus factors is attack by the antibodies developed during the first delivery (when the mother's blood came into contact with the fetus's blood); the mother's antibodies attack the fetus's blood, causing it to lyze and the fetus's body converts the Hb into bilirubin, turning the fetus's body yellow; most babies become anemic and may or may not survive; the liver will enlarge and attempt to produce more RBCs to supplement the destroyed RBCs, sometimes releasing nucleated RBCs; if they do survive, they are usually mentally impaired due to a precipitation of bilirubin in neuronal cells (a condition called kernicterus)
Term
How does one treat erythroblastosis fetalis?
Definition
one treatment is replacing all the baby's blood with Rh- blood; this will prevent destruction of RBCs by lingering anti-Rh+ antibodies (which will linger for about a month) and the babies Rh+ blood will replace the Rh- blood after 6+ weeks
Term
How does one prevent erythroblastosis? How does it work?
Definition
1. infusion of anti-D antibodies into the pregnant mother, starting at 28-30 weeks
2. the anti-D antibody will inhibit the D antibody-producing B cells and also attach to present D antibodies and disable them
Term
What is the most dangerous acute risk of tranfusing mismatched blood? What causes it?
Definition
1. renal failure
2. lysis of RBCs releases toxic substances that cause significant vasoconstriction in the kidneys, loss of RBCs and release of toxic substances can cause circulatory shock, and the free Hb is often too much for the present haptoglobin and much of the excess leaks through the glomerular membranes into the renal tubules; if the Hb concentration in the renal tubules is high enough, Hb can precipitate and block the tubules
Term
What is the difference between immediate transfusion reactions and delayed transfusion reactions?
Definition
immediate - antigen-antibody reaction activates the complement proteins; this is more likely to occur with A and B antigens
delayed - antibody-antigen reaction results in agglutinization, which triggers macrophage phagocytosis; this is more likely to occur with Rh antigens
Term
How much bilirubin can the liver process from hemolyzed blood daily?
Definition
the equivalent of 400 mL of blood
Term
What are the types of transplantation? Describe them.
Definition
a. autografts - a transplant from one part of the patient's body to another (such as a blood vessel or skin)
b. isografts - transplants between twins
c. xenografts - transplants between species (such as pig heart valves)
d. allografts - transplants between different people
Term
How long can grafts last when they are properly matched to their recipients? Which organ has the best survival rates? Which has the worst survival rates?
Definition
1. 5-15 years
2. kidney transplants
3. heart and lung transplants (cotransplant)
Term
What is the HLA system?
Definition
a system of surface antigens that exists on the surfaces of all nucleated self cells
Term
What is the usual reason for a mismatched organ? What measures do physicians take to prevent rejection of an organ? What is a danger with these measures?
Definition
1. activation of T-cells and a mismatch of MHC class II genes
2. suppressive therapy - giving the patient immunosuppressive drugs to prevent destruction of the cells; combinations of these drugs usually work best
3. they increase the likelihood of infection or cancer
Term
List the types of immunosuppressant drugs given to prevent organ rejection. Describe what they do.
Definition
a. glucocorticoids - limits the movement of granulocytes into tissue
b. azathiopriine - inhibits the functioning lymphocytes; it inhibits mitosis to reduce proliferation of B and T lymphocytes
c. cyclosporine - specifically a T-cell inhibitor; cyclosporine A is often used in combination with FK506, which bocks IL-2 signaling and prevent T helper cells from activating macrophages, etc
Term
How are organs testing for rejection?
Definition
organ-specific cells with the HLA antigens on the surface are isolated from the donor and then mixed with WBCs of the recipient, after which trypan blue is mixed in; if the antibodies mark the recipient cells for rejection, the membranes of the donor cells will be damaged and the trypan blue will leak into the donor cells; otherwise, the donor cells will not be harmed
Term
Define: hyperacute rejection, reperfusion injury. How is reperfusion injury avoided?
Definition
1. rapid rejection from antibodies in the body attacking surface receptors of an organ
2. oxidative injury that occurs when an organ is hooked up to blood supply in the recipient's body.
3. slowly introducing blood supply to the organ
Term
What is the probability of MHC class II identity between siblings? What is the 2-year survival rate if 1-2 loci of MHC I are mismatched? What is the 2-year survival rate is 1-2 loci of MHC II are mismatched?
Definition
1. 25%
2. 90%
3. 70%
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