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Help with human biology questions please

Explain why type B positive blood cannot be given to a patient that has a blood type that is A negative.
We need to explain this with respect to 2 different blood group categories, namely the ABO system and the Rhesus system.

With ABO, a person with blood group B will will carry the B antigen on his/her erythrocytes, WHEREAS a person with blood A will have ONLY A antigens on his/her erythrocytes AND NO B antigens - hence if B group blood is transfused to this 2nd patient, the latter will produce antibodies against the B antigen [which it will see as "foreign"], and a transfusion reaction will occur i.e. the recipient will attempt to destroy the transfused B group blood. This reaction can be serious, even life-threatening.

With the Rhesus system, a person who is positive, will carry the Rhesus antigen [also called "D"], WHEREAS a person who is negative will not. In a similar way to the above, the negative recipient will reject the positive blood. [An example seen relatively commonly is when a Rhesus -ve woman has a baby with a Rhesus +ve partner, in which event, the mother's blood might see her own baby's blood as foreign and reject it. This results in the baby being born with Haemolytic disease of the newborn, which will require immediate therapy.

Hope this helps!

If you need further guidance, please feel free to PM me or4 tag me.

Be safe!
M

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