Explain why a person with type AB blood can donate blood only to a person with the same?

A person with A-type can also donate to someone with AB-type as well, provided there is no conflict with any other bloodtyping (rhesus positive or negative being the major one). This is because antibodies on the blood cells in the donor are treated as invaders if they are not the right type. The recipient's body then acts in the same way as it would when fighting off a normal virus or invader; they attack the foreign cells and this creates clots throughout the circulatory system. This poses serious risks to the recipient, as they can block the arteries and veins and cause hypoxia and anaemia, as well as heart problems with life at major risk.