think of immunity as a battle, which it
basically is, H. pylori is a case of enemy
soldiers wearing the uniforms of your
own side; lupus is your soldiers being
knocked out by friendly fire.
There are several ways your body
can reject an organ. Hyperacute rejec-
tion can happen within minutes of
transplantation when the body has
preëxisting anti-donor antibodies; it
has met this enemy, or something sim-
ilar, before, and is ready to attack im-
mediately. In hyperacute rejection, large
blood clots rapidly form, obstructing
the blood supply of the donor organ.
This is what would happen if a “regu-
lar” pig organ were used for transplant;
all humans have roughly one per cent
of their antibodies devoted to attack-
ing what are called alpha-gal sugars.
Most mammals have these sugars, but
humans don’t. The alpha-gal gene is
one of the genes that were knocked out
in the transplant pig.
Besides gene-editing—which be-
came practicable only recently and is
not an option for donated human or-
gans—the main approach to getting a
patient’s body to accept a donor organ
has been to suppress the immune sys-
tem. This is dangerous. The first heart
transplant that had some success took
place in 1967 in South Africa. Thanks
to immunosuppressants, the patient did
not immediately reject the organ; also
because of immunosuppressants, the
patient died of pneumonia eighteen
days later. Even when a recipient makes
it past both hyperacute rejection and
postoperative infections, transplant or-
gans can fail later, owing to what is called
chronic rejection, a process that is not
entirely understood.
One pioneer of heart-transplant sur-
gery said, “We were excited about sew-
ing in the heart, which is...when you
think about it technically, quite a sim-
ple plumbing job.” The history of ad-
vances in transplantation is, arguably,
more accurately understood not as a
history of surgery but as a history of
immunobiology. The transplant sur-
geons saw that rejected organs were in-
filtrated by cells; trying to understand
the mechanism prompted the tremen-
dous bloom in immunobiology. To re-
turn to the limited but apt battle anal-
ogy, immunobiology is the science that
develops diplomats, who suggest that
there are alternative ways to respond to
the presence of the foreign agent—that
there’s a way to get along.
Allan D. Kirk, a transplant surgeon
in the Duke University Department
of Surgery, who has worked in the field
for more than thirty years, said, “In the
nineteen-seventies, every transplant
case was like a miracle. To decide to
be a transplant surgeon was like say-
ing you wanted to be an astronaut.”
Until recent advances, he said, enthu-
siasm about xenotransplantation had
not been scientifically justified. “It was
driven by companies that would drop
a bunch of money without knowing
the science. But this is the first time I
think the enthusiasm is scientifically
credible.” Kirk attributed the change
to genetic engineering and to better
immunosuppressive drugs. “CRISPR
has made it logistically more reason-
able to change all the genes you need
to change,” he said. “And immunosup-
pressive drugs are not as brutal as they
once were. We can make more refined
interventions.” There are even some
transplant patients walking around who
no longer take any immunosuppressive
drugs, or who take them once a month.
At some point, their bodies learned to
accept the foreign organ as self. “The
problem is that no one knows how it
happened,” Kirk said.
Kirk then turned philosophical, while
apologizing for doing so. “All of us were
allogenic tumors at one point,” he said.
“Allogenic” refers to being foreign, but
from the same species. “That’s called a
fetus. Our mothers didn’t reject us—at
least not until we turned thirteen and
burned down the garage. So we knowas a species how to not reject foreign
organs. Our biology already knows how
to do that, and we need to catch up.”W
hen news of the pig-heart oper-
ation was announced, one trans-
plant surgeon found it especially mean-
ingful. Robert Montgomery, the director
of the N.Y.U. Langone Transplant In-
stitute, had received a heart transplant
in 2018. He had a genetically linked heart
condition, which he learned about when
his brother Richard died suddenly at age
thirty-five. Montgomery, a surgical in-
tern at the time, connected this to his
father’s death, some years earlier, from
what was erroneously attributed to a vi-
rus-induced heart condition. Three of
Robert’s children have the same condi-
tion, as do Richard’s two daughters.
I met Montgomery on Novem-
ber 23rd, the day after he completed the
transplant of a pig kidney to a human,
the third such operation ever; the first
had also been performed by Montgom-
ery’s team, two months earlier. (The Uni-
versity of Alabama at Birmingham did
a similar operation in between.) Mont-
gomery had a mustache that made him
look like Wyatt Earp, though it was less
dramatic than the one he had had be-
fore Covid; he had trimmed it for height-
ened hygiene protocols. Nikki Lawson,
a transplant-research nurse coördinator
who has been on his team for almost
two decades, “was so upset when I had
to trim it,” he said, laughing. “She said
she thought it was the source of my
power.” Montgomery’s team’s kidneys
also came from Revivicor; they were
attached to brain-dead human bodies,
demonstrating that they would not be“Ordered fifty-eight days ago and it’s here already!”