There is nothing in Jewish law that would preclude a person from benefiting from a blood transfusion (or donating blood, for that matter).
Furthermore, according to Jewish belief, saving a life is one of the most important mitzvot (commandments), overriding nearly all of the others. (The exceptions are murder, certain sexual offenses, and idol-worship—we cannot transgress these even to save a life.) Therefore, if a blood transfusion is deemed medically necessary, then it is not only permissible but obligatory.
All the best,
Rochel Chein for Chabad.org