The Warsaw Treaty Organization (also known as the Warsaw Pact) was a political and military alliance established on May 14, 1955 between the Soviet Union and several Eastern European countries.
1 Donors with blood type A... can donate to recipients with blood types A and AB. 2  Donors with blood type B... can donate to recipients with blood types B and AB.  Donors with blood type AB...
If you have type O blood, your red blood cells will not have any antigens and therefore produce both anti-A and anti-B antibodies. This means you must be careful and only receive blood from other type O people. But, because your blood has no antigens to react with the immune system, you can donate blood to anyone.