What are the dangers of giving a person a transfusion when the blood types don鈥檛 match?

What can happen to the person as far as reactions?

..........and also what causes these reactions

Wrong blood types will immediately clump together in clots and cause heart attacks, strokes, or death. The blood cells have different types of antigens: A, B and none. If both A & B antigens, it is type AB, only A antigen is type A, B antigen type B, and no antigens is type O. Because of this, a type AB person can receive any type of blood, because of both antigens. However, type O can only receive type O, because the presence of the foreign antigens on the blood cells will cause the body to attack the cells, causing clumping, and other badness. The body treats the new blood like an invading entity, and tries to protect itself.

the person will reject the blood as a foreign object causing the release of antibodies etc etc

it's a natural defense system

DEATH!!

You get anaphylactic shock then you die if your nurse doesn't unhook the wrong blood and administer proper countermeasures.

There was one case where a nurse gave a patient the wrong blood type and the patient died. The patient's family sued the nurse, her supervisor, the laboratory, the blood bank, the pathologists in charge of the laboratory and the blood bank, the resident physicians, the attending physician and everyone else in between. Patient was postpartum and had severe bleeding, that's why they needed a transfusion. The nurse was so tired (did a double shift) that she made a mistake (unexcusable I know, but it happens).

a mutation can occur and the person could have a great chance of dieing.