BSI 2 Lecture 12: Immunology Flashcards
What must be considered when giving life-saving blood transfusions or transplanted organs?
The antigens expressed on RBCs
How many surface antigens do RBCs possess?
Many, but most are only weakly antigenic and have little medical significance
What are the 2 significant surface antigen groups?
O-A-B groups and Rh groups
What are the two antigens responsible for most transfusion reactions?
A and B
What are A and B composed of?
They are proteins with added sugar groups (glycoproteins)
What determines which antigens your RBCs express?
Genetics
What is Group A?
RBCs express antigen A
What is Group B?
RBCs express antigen B
What is Group AB?
RBCs express both A and B antigens
What is Group O?
RBCs don’t express either antigen
What else does the person possess besides the antigen on their RBCs?
Antibodies to the group or groups they do not express
What antibodies does blood group A possess?
Anti-B
What antibodies does blood group B possess?
Anti-A
What antibodies does blood group AB possess?
Neither anti-A or anti-B
What antibodies does blood group O possess?
Both anti-A and anti-B
Why are people with blood type O called “universal donors”?
Because they can only receive blood from other O blood types, but since they don’t present any antigen, they can donate to anyone
What happens to the production of blood group antibodies throughout life?
At birth it’s about 0. From about 2-8 months is when the antibodies start producing and it reaches a maximum after 8-10. It decreases gradually throughout life.
What type of antibodies are these?
Mostly IgG and IgM
What happens when RBCs come in contact with specific antibodies for the antigen(s) expressed on their surface?
Agglutination, because the antibodies have multiple binding sites that clump RBCs
What happens to the RBCs once they are agglutinated?
They either lyse due to their deformed membranes, or they are phagocytized by WBCs
The _______ blood group is the most common and the _______ blood group is the least common.
O, AB
What are Rh antigens?
They antigens also expressed on RBCs that can cause transfusion problems.
How is the Rh antigen different than the O-A-B antigens?
Antibodies usually aren’t produced until there is exposure to the antigens. To produce a significant response, there needs to be repeated exposure
What are the 6 common types of Rh antigens?
C, D, E, c, d, and e
If a person has the C-Rh antigen, will they have the c-Rh antigen?
No, and this is the same with the other pairings
How do you read the blood grouping test? (Need to know this for 6 free questions)
You will see Anti-A, Anti-B, and Anti-D with a circle above all three. If the circle is agglutinated, then that is what blood type they have. If the Anti-D is agglutinated, it’s positive. If not, it’s negative.
What happens if an Rh- individual is given Rh+ blood with no previous exposure?
There won’t be an immediate serious reaction, but antibodies will be produced and will agglutinate any remaining Rh+ antigens
What happens is there is repeated exposure of Rh+ to an Rh- individual?
The effect could become as serious as an O-A-B reaction
What is Erthyrobastosis fetalis?
When a newborn gets anemia because the mother was Rh- and the baby was Rh+. The mother produces antibodies that can cross the placenta. Just like before, the first time isn’t severe, but gets worse with repeated exposure (additional kids).
As well as being anemic, what else can happen to the child when born?
The hemolyzed RBCs increase hemoglobin recycling which increases bilirubin levels. This can cause jaundice.
Unfortunately, the mother’s antibodies float around for 1-2 months in the child’s circulation. What does this cause in the child?
Since RBC production is primarily in the liver and spleen, they swell greatly in attempt to compensate and produce many immature RBCs.
What is Kernicterus?
When neurons accumulate precipitated bilirubin intracellularly causing their destruction
What is a possible treatment for Kernicterus?
Blood exchanges which help maintain decreased bilirubin levels until the mother’s antibodies have been eliminated
What is the most lethal component of these transfusion reactions?
Kidney failure (it can occur within minutes of a transfusion)
What causes kidney failures in these reactions?
1) vasoconstriction because of chemicals released by hemolyzed RBCs
2) Circulatory shock decreases blood pressure and further decreases kidney function
3) increased amounts of Hb leaks into the kidney tubules and precipitates as water is reabsorbed therefore blocking them
If kidney failure is not resolved death can follow in how many days?
7 to 12
What is an autograft?
A transplant of tissue or organs within the same person/animal
What is an isograft?
A transplant of tissue or organs within identical twins
What is an allograft?
A transplant of tissue or organs between individuals of the same species
What is a xenograft?
A transplant of tissue or organs between different species
Which type of graft causes the most issues?
Xenografts
Which type of graft usually causes very little problems and why?
Isografts because identical twins are essentially clones
Which type of graft is the most common and requires tissue matching?
Allografts
What are MHC proteins also known as in humans?
Human Leukocyte Antigens (HLAs)
Where are HLAs found?
On the cell membranes of WBCs
What is used to type HLA’s
A special dye instead of looking for agglutination
What would happen if the immune system were suppressed for a transplant?
There would be no rejection; however, a single pathogen could then kill the person
What class of medication is used to help suppress T-cells (the ones responsible for rejection)?
coritsol/glucocorticoids
It is almost impossible to synthesize a drug to interact with specific peptide receptors, but what can be generated to interact specifically with peptides and their receptors?
Antibodies
