Organ rejection is due to your immune system attacking the new tissue that it finds foreign. Your immune system works to protect you from disease from foreign materials that may enter your body. This is how it attacks viruses and bacteria that may cause infection. Without getting deep into immunology, it knows how to tell "self" from "non-self" by reading certian types of molecules present on the outside of your cells. Donor blood is matched by type to the recipient so that these molecules match what your immune system knows as "self". However, organ tissue has different types of molecules that aren't as easily matched (can only be done perfectly in identical twins). When cells that have different types of molecules or none of these molecules at all are present, your immune system thinks that the cells are invaders instead of friendly tissue. This is why people who have received organ transplants usually have to be on anti-inflammatories and immunosupressants for the rest of their lives.
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Actually, blood cells are rejected same as organs even if the blood type is similar. But the rejection is minimal so transfusion is OK.
Organ rejection is due to your immune system attacking the new tissue that it finds foreign. Your immune system works to protect you from disease from foreign materials that may enter your body. This is how it attacks viruses and bacteria that may cause infection. Without getting deep into immunology, it knows how to tell "self" from "non-self" by reading certian types of molecules present on the outside of your cells. Donor blood is matched by type to the recipient so that these molecules match what your immune system knows as "self". However, organ tissue has different types of molecules that aren't as easily matched (can only be done perfectly in identical twins). When cells that have different types of molecules or none of these molecules at all are present, your immune system thinks that the cells are invaders instead of friendly tissue. This is why people who have received organ transplants usually have to be on anti-inflammatories and immunosupressants for the rest of their lives.
The second answer was correct but did not answer your query.Red blood cells live about 42 days the transplant is as long as you live.
I.E. one is an emergency ,{ the transfusion}, the transplant is as long as you are alive or the organ is. I am a biologist.