BL Immunohemotology Flashcards
Universal blood donor
O negative
- no antigens
(but indiv, make antibody A and B)
Universal recipient
AB positive
- no antibodies
(but indiv make antigens A and B)
greedy bastards! Take and never give.
Do red cells have MHC?
Plasma cells?
No MHC on red cells ( MHC I occurs on all nucleated cells) - they are rejected in a different manner than organ donations (No NK cell activation)
Yes MHC on plasma cells (so blood donations can still elicit blood transfusion rejection.
antibody class of most ABO isohemagglutinins
What is Ab class of Rh(D)?
Predominantly IgM
- This is good because if they were IgG, then they could cross the placental barrier and cause an attack on the child = abort fetus
we could never have babies!!!
Rh(D) is IgG which can cross placenta
ABO antigen situation in a person of Bombay blood type
• Bombay people lack the transferase gene to put the final fucose sugar (red triangle) on the “core”.
- Often mistyped as “O”
- Make anti-A, anti-B, and anti-O … RUH ROH!
crossmatch
Crossmatch is a test to answer the question:
“are there antibodies in this recipient’s plasma which can react with antigens on this donor’s RBCs?”
-used in transfusion
What does aggluttination and hemolysis during crossmatch indicate?
agglutination (cloudy) and hemolysis (red) -
indicate antibody reactions with complement activation
Which coombs test is useful for Autoimmune hemolytic disorders? crossmatching before transfusion?
Autoimmune hemolytic disorders - Direct coombs test
- we are detecting human Ig on RBC surface
Crossmatching before transfusion - Indirect coombs test
- bc we are taking plasma from recipient
What question is the direct coombs test asking? Indirect?
Direct: Is there antibody already on the cells that I am interested in?
Indirect: Is there unexpected antibody to red cell antigens in the plasma of this recipient?
heterophile antibody
an antibody that has the capacity to bind with multiple antigens (that are similar but not exactly the same)
- Ab has potential to attack bad guys but also attack you!
Hemolytic Disease of the Newborn
- What is it?
- Also called erythoblastosis fetalis
* Occurs in Rh(D)+ babies of Rh(D)- mothers
Consequences of HDN (erythoblastosis fetalis) to the baby:
- Born jaundiced
* High levels of bilirubin can cross BBB and damage the basal ganglia → cerebral palsy or death
How to prevent HDN (erythoblastosis fetalis)?
- Preventable if @ time of first Rh(D)+ delivery you can give her IgG antibody to Rh(D). (RhoGAM)
- These opsonize with baby’s cells that cross the placental barrier and destroy them before she can mount a response
• Note: She is NOT made tolerant to Rh(D), so she MUST receiver RhoGAM each time that she may be exposed to Rh(D)+ cells
Explain the situation in which ABO hemolytic disease of the newborn can occur.
Very similar to hemolytic disease of the newborn with Rh(D)
• Some women, make anti-ABO IgG instead of/in addition to IgM (that’s bad!!).
So if an O, A, or B mother has an AB kid, the kid’s blood is not long for this world
Dad needs to have exact same blood as mom for this not to matter.
