A man has 'caught' a kiwifruit allergy from his sister after receiving a transplant of her bone marrow.
European researchers say it is the first proof the surgery can spread food allergies.
They were able to conclusively demonstrate that the donor's bone marrow cells were responsible for triggering the reaction, and said it paved the way for further insight into how allergies started - and, more importantly, how to treat them.
The 46-year-old man developed tingling and swelling of the lips and mouth when he ate a kiwifruit after his surgery.
The researchers managed to isolate the specific cells in his blood that were reacting to the presence of kiwifruit, and confirmed they had originated from his sister's bone marrow.
They might now be able to check whether bone marrow transplants could also be used to treat food allergies.