A person with ‘O’ blood type should receive blood from ‘O’ blood type only. Blood transfusion with other blood types is dangerous in this case. What can be the reason?

‘O’ blood type person has no antigens on his RBC. But he has anti A and Anti B antibodies in his plasma by birth, they react with antigens on the RBC’s of recipient (A, AB and B) and cause clumping of donor’s RBC which mix in his blood. This agglutination of RBC in his blood vessels causes death.