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...
Con: Type O negative carriers will have anti-A and anti-B antibodies against A B, Rh blood group antigens. Thus, a type O individuals can only accept type O blood. Introduction of other types of blood A, B, or AB may cause immune responses and ultimately, death! Type O negative is the rarest, which makes the supply of type O more scarce than other types. Pro: Type O negative is known as the universal donor type. This type of blood can be donated to anyone. Blood group O indivuduals do not have either A or B surface antigens on their red blood cells. Thus, one may donate and save many lives! (and you would really help people with blood O type!)