Hello eddeswife
To begin with, Im very sorry for the delay in getting back to you. The simple answer is yes, some allergies can be transfered through a blood transfusion. This was discovered some time ago. The research is still not complete and it is not clear if some allergies are more transferable than others or if you will always get an alergy or just occasionally. The research here is hazy. However yes it is possible.
Sorry again for the delay.