By Dr. Becker
Ever heard of a xenotransfusion? (Hint: “xenos” is Greek for strange or foreign.) It’s a transfusion of blood from one species to another, and is rarely attempted. But it was done just a few months ago, and now a feline in Florida has canine blood coursing through his veins.
Buttercup Needed a Blood Transfusion, and Fast
Buttercup, an orange tabby, lives in Key West with his human, Ernie Saunders. Saunders noticed that Buttercup seemed lethargic even by housecat standards, and took him to the veterinarian.
The vet, Dr. Sean Perry of the Marathon Veterinary Hospital, ran a few tests and discovered that Buttercup’s red blood cell count, which should have been at least 35 percent, was only 7 percent. Diagnosis: Buttercup was severely anemic and needed a blood transfusion.
Unfortunately, it was going to take awhile for compatible cat blood to be shipped to the Keys, and Buttercup didn’t have much time. (Just like humans, cats and dogs have different blood types, but dogs have a universal donor blood type and are larger animals, so their blood is more often available at animal blood banks.)
Dr. Perry recommended that Buttercup receive a transfusion of dog blood because his blood volume was dangerously low.
"It's a situation where you can't give type A blood to a type B blood cat because it'll cause a severe immune reaction," Perry said. "It was actually safer to give the cat dog's blood. It's a practice that's been used in the past but it's not common."
History of Dog-to-Cat Xenotransfusions
In a study published in 2013 in the Journal of Feline Medicine and Surgery,1 researchers reviewed the historical practice of xenotransfusion. The procedure has been documented in veterinary literature since the 1960s, and is currently practiced in some countries, including Australia, France, and Italy.
The researchers found that from 1962 to 2013, there were four studies and one case report documenting the transfusion of canine blood to cats (62 cats total). In most instances, the transfusions were successful, indicating that cats don’t produce antibodies against canine red blood cells. In other words, their immune systems didn’t react to the presence of foreign red blood cells.
Some of the kitties did have mild reactions to the transfusions, including rapid breathing, elevated body temperature, and jaundice.
However, subsequent transfusions given a week or more after the initial transfusion caused severe reactions in the cats, including blood in the urine (hemoglobinuria), anaphylaxis, and death. This suggests that after the initial transfusion, the cats’ immune systems were prompted to develop antibodies against the canine antigen.
The researchers also learned that canine red blood cells have a much shorter half-life – less than four days – when transfused to feline patients.
The study authors concluded that whole blood or packed red blood cells from dogs should not be used for transfusion in cats as a standard practice. It can be considered a treatment option in certain specific cases, such as when compatible feline blood or hemoglobin-based oxygen carrier solution is not available, and as long as the kitty has never had a xenotransfusion before.
It’s also imperative that the cat’s owner is advised of the risks and benefits of the procedure.
Buttercup Receives Greyhound Blood
In mid-September, Dr. Perry performed Buttercup’s blood transfusion – which was considered lifesaving. Greyhound blood packs from a blood bank that separates red blood cells from plasma were used.
Buttercup showed no signs of rejection during the transfusion, and he was sent home on a regimen of steroids and antibiotics. He’ll need to return for regular checkups with Dr. Perry.
"Buttercup is at home and doing quite well," Perry said. "What we try to do with transfusions is buy some time in order to get Buttercup's bone marrow to kick into gear. Buttercup has developed red cells of his own now."
Buttercup’s vets aren’t sure why he developed anemia, but hopefully it was a one-time occurrence, or the cause is ultimately determined and resolved. I also hope Buttercup didn’t need to stay on those steroids for long, due to the potential for severe, debilitating and life-shortening side effects.