Someone said that Brantly is a universal donor.
I think we’ve deduced he’s A+ because if he was universal (O-) or nearly universal (O+) he would have been able to donate to Duncan.
Do you know who that someone is? All reports that I'm aware of indicate his blood type was not a match for Duncan.
Clearly not if Duncan wasn’t a match. Maybe it’s a subtype of O- which has to match also? (In the OJ Simpson trial they talked about subtypes of blood which were different than ABO +/-.