In blood transfusions, which is better: minor matches or major matches?

Minor matches kill off some of the recipient's blood cells, and major matches kill off all of the donor's blood cells. Which is better?
Answer:
"Great care is taken in cross-matching to ensure that the recipient's immune system will not attack the donor blood. In addition to the familiar human blood types (A, B, AB and O) and Rh factor (positive or negative) classifications, other minor red cell antigens are known to play a role in compatibility. These other types can become increasingly important in people who receive many blood transfusions, as their bodies develop increasing resistance to blood from other people via a process of alloimmunization." - from widipedia

The greater the match, the better the transfusion, because the recipient's immune system does not attack the donated blood. The "major" matches are the A, B, AB, and O types plus Rh factor, and then there are the "minor" items that are not a problem with a one time or a few infusions.

The donor's blood does not "attack" the recipient's blood, nor does the recipient's blood kill off the donor's blood. If there is a poor match, or none, the recipient's immune system, which to be sure is largely in the blood, attacks the donated blood products, and the recipient could die of a kind of allergic reaction. When the blood types match for A, B, AB, O and Rh factors, no such reaction occurs. Matching even more finely is needed when people need ongoing transfusions, because they build up a resistance to these otherwise untroublesome factors and they become troublesome.

---