Transfusion Science III - Drug Induced AIHA Flashcards
1
Q
List the 4 mechanisms of drug-induced AIHA
A
- Drug Adsorption mechanism
- Immune complex mechanism
- Membrane modification mechanism
- Auto antibody formation mechanism
2
Q
What is an example of a drug that leads to Drug Adsorption mechanism?
A
Piperacillin antibiotic
3
Q
Describe the drug adsorption mechanism
A
- Drug binds to RBC
- IgG Drug antibodies formed
- Drug antibody binds to drug on RBC
- IgG coated RBCs phagocytosed
- Extravascular
4
Q
What are two examples of drugs that lead to Drug Immune Complex
A
- Cephalosprin antibiotics like cefotetan and cephalothin
- Quinidine
5
Q
Describe the Drug Immune Complex mechanism
A
- Drug antibodies formed
- Drug antibodies bind to drug in plasma
- Drug - antibody complex non specifically binds to RBC
- Complement activated
- Membrane Attack Complex
- Intravascular
- Renal failure
6
Q
Name a drug that leads to membrane modification mechanism
A
Cephalosporin like cephalothin
7
Q
Describe the Membrane Modification Mechanism
A
- Drug binds to RBC
- Membrane structure changes
- Immunoglobulin proteins bind to exposed neo antigens
- Phagocytosed or MAC
8
Q
Describe the Auto-antibody formation mechanism
A
- Blood pressure drug methyldopa causes production of an auto Rh antibody
- Triggers WAIHA
9
Q
What are the treatments for DIHA?
A
- Discontinue drug
- Treat the condition
- Prednisone drug
10
Q
What are the expected SEROLOGICAL results for Drug adsorption, immune complex, and membrane modification
A
- Positive DAT
- Negative antibody screen with regular screening cells
- Positive antibody screen with drug-coated screening cells
11
Q
What are the expected SEROLOGICAL results in auto antibody formation mechanism
A
- Positive DAT
- Positive antibody screen with regular screening cells
- Indistinguishable from WAIHA
