Q. I’m currently doing my rotations at Children’s Memorial Hospital’s blood bank and I was reading the standard operating procedure for washing red cells. One of the conditions in which they need to be washed is paroxysmal nocturnal hemoglobinuria. Do you know why this is?
A. The reason for washing red cells for people with PNH is to get rid of any ABO incompatible plasma.
In a person without PNH, ABO incompatible plasma doesn’t cause any perceptible hemolysis. The antibodies in the donor unit probably just get diluted out enough that they don’t have much of an effect. Or perhaps they get sopped up by other ABO antigens on other cells (did you know that you have A and B antigens on cells besides red cells?! Weird.).
But patients with PNH are super susceptible to complement-induced red cell destruction. They lack the ability to anchor certain proteins (including proteins that protect the red cell against complement) to the red cell membrane. Patients with PNH have a hard time down-regulating even a small amount of complement activation – so theoretically, a transfusion of even a small amount of non-ABO compatible plasma could lead to hemolysis. There have been a few cases of hemolytic transfusion reactions in patients with PNH that have been attributed to this phenomenon…so in 1948, blood banks began washing red cells before giving them to patients with PNH.
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- rachel said Ahh. Thank you very much!!!
- Abu Jar said Nice explanation….
- M said Thank you! You don’t know how much it helps me!! 🙂
- sai teja said Nice explanation
- Prashant waichal said Excellent and simple to the point review
- Julia said Thanks again for the clarification Dr Krafts!
- Kyaw said Thanks a million. This helps me a lot.
- Kristine said Good question – I believe so! I can’t think of an example of a type II hypersensitivity...
- gbadebo said Nice! But this brings up another question- are all examples of type II hypersensitivity reactions au...
- Dr.sunil Kumar.c. said very useful and nice explanation thank you so much…
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- dr sunil kumar laad said excellent