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...
O-blood can donate to anyone, but can only get blood from other O-'s. If a type A donates to a type O, the antibodies from A collide with the anti-A antibodies from O, and can cause death to the person, or brain damage to a baby that's about to be born.