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...
AB negative blood type individuals can receive blood from A-, B-, O- and AB- only. This because AB- type has both A and B antigens but has no Rh antigen. 2. Again due to absence of the Rh antigen but presence of A and B antigens, the AB- blood type donor can only donate blood to AB- and AB+ blood type individuals.