Answer
A transfusion reaction occurs when blood type of a donor is incompatible with the blood type of the recipient. For example, if packed RbCs or whole blood from a Type A donor is transfused into a Type B recipient, the anti-A agglutinins (antibodies ) of the recipient will attack the A antigens ( agglutinogens) on the RBC membranes of the donated blood . This reaction would cause he donor erythrocytes to clump and block blood vessels-- for a brief period. Subsequently, fibrinolysis would cause the clumped RBCs to break up and spill hemoglobin into the plasma.. The plasma
would transport the dissolved hemoglobin to the kidneys for excretion. However, the kidneys would soon become overloaded with the large amount of hemoglobin , and be unable to process and excrete all of it. As a consequence, kidney functions would be impaired . In time, kidney failure would develop. Such an acute hemolytic reaction constitutes a life-threatening medical emergency.
Work Step by Step
Transfusion reactions are usually caused by failure to properly type and cross-match blood types with respect to the ABO system. Nevertheless, transfusion reactions can take place because of incompatible transfusions related to the Rh system of antigens. People who are Rh+ve do not normally develop anti-D antibodies in their blood. Still an Rh-ve mother may develop anti-D agglutinins if she has an Rh+ve baby and some of the baby's RBCs somehow get into the mothers circulation during pregnancy or at childbirth. This would sensitize the mother to the D antigen. If such a mother has another Rh+ve embryo/fetus. the sensitized mother wiould quickly make antu-D agglutinins which would get into the baby's blood stream by way of the placenta. The result would be a condition called erthroblastosis fetalis :the the mother's antiD antibodies attack the baby's Rh+ve RBCs' and cause clumping and hemolysis. A baby that develops such a condition is called a blue baby ,and the condition is called hemolytic disease of the newborn or erythroblastosis fetalis . When such a baby is born it must receive a blood transfusion immediately, if it is to survive.
