I remember when we did the initial bloodwork and review for the transplant, we were told my husband was AB. They said that was the best place to be as anyone would match - A, AB, B or O - and was usually one of the quickest ones on the list. They did say one of the longest waits was O as only an O donor could match - go figure. Sounds like Fr Pat has given you good advice, so you may want to check out about an exchange program.