Xander Salsitz was born at the University of Michigan Medical Center on April 28, 2003. He flourished for the first seven years of his life. But in late 2011, when he was a second grader at the Steiner School, “something weird happened,” says his mother, Emilie. “He had a strange reaction to a vaccine.

“Within a year or two, we saw varying symptoms of damage: bleeding gums, and a series of illnesses that he struggled to overcome.”

Emilie and her husband, Aaron, run a mom-and-pop computer services company (the Observer is a client). Technically minded and widely curious, they had taken an unusual step when Xander was born: they had about 60 milliliters of blood from his umbilical cord collected and cryogenically frozen at the New England Cord Blood Bank (NECBB), thinking it might have some future scientific use.

“We had no idea how critical that decision would be, how it would play such an important role in our lives,” Emilie says.

Doctors sent Xander to U-M labs for further tests. When the results showed a “ridiculously low” blood count, Emilie recalls, he was rushed to the emergency room. Medical staff immediately gave him a transfusion of platelets, the cell fragments that blood needs to clot. “If he had sneezed, he could have lost his life” from uncontrollable bleeding, Emilie says. “The situation was that serious.”

In January 2012, Xander was diagnosed with myelodysplastic syndrome (MDS). It was the start of an epic medical journey that involved countless near-death experiences. His blood-producing bone marrow was killed and replaced three times.

That tale is still difficult for his parents to relate. But today, Xander is a healthy sophomore at Pioneer and an aspiring musician.

He’s also a medical chimera–a person whose body has two different sets of DNA. Most of his genes come from his parents, of course. But some are now a gift from a stranger, a young university student in Germany who answered a desperate call for help.

MDS is a group of disorders in which the bone marrow has trouble producing mature blood cells. Usually symptomless in the early stages, it eventually causes fatigue and shortness of breath. Sufferers will become unusually pale, bruise and bleed easily, and may see pinpoint-sized red spots under the skin. They contract infections frequently because their marrow isn’t producing enough white blood cells.

Most victims are over sixty and many have been exposed to industrial chemicals, tobacco smoke, or pesticides. The fact that none of those circumstances applied to Xander didn’t make his illness any less perilous. Specialists told Emilie and Aaron that their son had two options: die or undergo a bone marrow transplant.

“Everything hinges on finding the right bone marrow donor,” Aaron says. “We were so grateful when a match was found for Xander.”

What matched initially, though, wasn’t bone marrow: it was umbilical cord blood. Other parents had donated it after their own child’s birth, hoping it might someday help someone like Xander.

Umbilical blood is rich in stem cells that can develop to play many different roles in the body. The idea was that the stem cells would replace Xander’s failing bone marrow, which would then start to produce new, healthy blood.

The procedure started with chemotherapy to obliterate his existing bone marrow stem cells. Without white blood cells, he would be vulnerable to life-threatening infections. “People all over the world prayed for Xander,” Emilie says.

Initially all went well–until he contracted a life-threatening shingles infection. Doctors had accidently neglected to administer an inexpensive antiviral medication that would have protected him.

Xander was rushed into isolation as his body struggled to combat the raging virus. The conflict reaction “blew out” the blood vessels in one eye, Emilie says. The transplant failed, and he was left dependent on blood transfusions to survive.

At one point, Aaron and Emilie were told their son had a 6 percent chance of living five years. The Salsitz family blog posts chronicle the long, painful, terrifying ordeals of procedures and near-death crises.

On Dec. 1, 2013, Emilie wrote,

“We have been working hard to keep him entertained while sitting day in and day out in his room. The monotony would get to anyone. We try to keep level heads and keep things moving forward, but being in the hospital for this long is like being in a big pressure cooker–at some point, it has to vent … As we move along at what seems like a snail’s pace, we are reminded of the last onset of [graft-versus-host disease] … This creates a huge drain on the family unit and the family budget. Thankfully, we have clients that are patient and understand our situation … As we start on the 8th week of admission, our funds are getting tight once again.”

They couldn’t know it at the time, but their son’s ordeal was only beginning. In all, he would spend nine months in the hospital–and require two more transplants.

Between medical expenses and time off work to be with Xander in the hospital, the family finances suffered. The couple drained their retirement accounts, remortgaged their home, and eventually launched an online fundraising campaign to keep them afloat financially; it raised $34,817.

Xander had his second transplant four weeks after the first–this time, using his own stored umbilical cord blood which was delivered from NECBB’s facility in Boston. Xander became the U-M’s first patient to receive a cord blood transplant from himself.

His own cells couldn’t cure Xander’s MDS, but they would give his body a chance to recover while doctors and the family decided on the next step. After receiving them, Xander started to regain strength. His bloodshot eye began to repair itself almost immediately.

He also began what would eventually be hundreds of sessions in a hyperbaric oxygen chamber. Aaron explains that the pressure perfused oxygen into his blood plasma, penetrating tissues beyond the reach of red blood cells to promote healing and increase stem-cell production.

His doctors recommended that Xander undergo yet another transplant. But this would be his last chance: three transplants are the maximum.

Aaron and Emilie allowed their son to make his own life-and-death decision. “At first he said no, having barely survived the first one,” Aaron recalls. “We supported his decision–until he steadily grew worse.

“That was when he made a deal with the doctors: if he could go to school and be with his friends, he’d agree to another transplant. All he wanted was to be just like the other nine year olds in his class.”

Xander got his day in school. And then a twenty-three-year-old German university student had marrow extracted from his hip bone, to save the life of a little boy he’d never met.

Michael Fengler got the first urgent request in February 2011: DKMS, an international nonprofit bone marrow donor center based in Ann Arbor’s sister city of Tuebingen, wanted him to provide new blood samples and take a physical exam.

He was told that his genetic markers matched those of a young boy in need of a bone marrow transplant. He immediately complied and waited to hear whether surgery or blood draws would be necessary.

Fengler is one of more than six million Germans who have registered as potential donors of hematopoietic (blood-forming) cells. It’s the highest rate in the world, more than double that of the U.S.

“Germans are very giving people,” says Lisa Hoekstra, who has matched patients and donors for U-M blood and marrow transplants since 2013. “Sixty percent of the donors on the National Marrow Donor Program are Germans.” Both Aaron and Emilie have family roots in Western Europe, which also made it more likely that a match would be found there.

Fengler was put on alert several times over the thirteen months during which Xander underwent his first two transplants. On March 25, 2013, he was once again asked to give a blood sample and take a physical.

He passed, and on April 28, he underwent a two-hour surgical procedure under anesthesia at a hospital in Cologne. A little more than a cup of marrow cells was collected from the back of his hip bone using a syringe and immediately shipped to Ann Arbor.

Fengler awoke with two sandbags below his hips, suffering from back and hip pain. He stayed at the clinic overnight and was released. His physician requested five days of sick leave. “Besides that pain for two or three days, I had no long-term negative physical effects,” he writes.

The DKMS paid for all his expenses and it would also have reimbursed him for sick leave if Fengler had needed it. Without sharing the recipient’s name, they also kept him informed of Xander’s condition and progress.

Then, in 2017, they passed on a request: Xander’s family would like to contact him.

In 2015, Xander didn’t visit the emergency room once. He entered sixth grade at Tappan, played clarinet in his first band performance, and sang in the choir.

On April 28, 2017, Xander’s family celebrated his fourteenth birthday soon after doctors reported that his metabolic and blood numbers showed no signs of disease. They also reminded the family that his blood was now entirely a product of Fengler’s genes–even his blood type was different.

Fengler accepted their request for contact. Two months later, the Salsitz family flew to Germany to thank Fengler and his mother, Pia, in person.

“Words cannot express our gratitude to Michael,” Emilie says.

In June, Fengler and his mother welcomed the Salsitz family to Bonn and they spent a day together. “This shared day was very exciting and I gratefully received some very personal gifts from Xander, as well as some very typical souvenirs from Michigan, i.e., a t-shirt from the University of Michigan,” Fengler writes.

“I somehow do feel a special connection to Xander, given that he has got my immune system. I would and can go through the process again, if my bone marrow is needed again–for Xander or someone else.”

Xander also feels a close connection. “It’s odd, but in some ways I’m beginning to look a little like Michael,” he observes, “hair color among them. I feel as if he’s like an uncle or a blood brother. I’m learning German so I can study in Germany.”

Bright, articulate, and highly motivated, Xander is very grateful to be alive. “Every day I realize how glad I am to be here,” he says. “I know an enormous number of people prayed for me and two healers worked with me. I had some terrific doctors and nurses.

“When I think back over those years, first, it’s with wonder at how much happened to me. Second, I try to enjoy what’s in front of me. And third, I realize how important it is for patients to become their own advocate.”

His sister Molly was six when the ordeal began. “I didn’t understand what was going on, just that Xander was really, really sick, and sometimes I felt angry about that.” She grins at her brother and adds, “He gotten a lot smarter, because of all the knowledge he absorbed in the hospital. He thinks like an adult.”

“Xander is everything any parent dreams of: a normal, average boy with exciting hopes and ambitions,” Emilie says. “We have gone from having absolutely no hope about his future to marveling at the limitless possibilities he has in store for him. All our wishes have come true.”

To learn more about the National Marrow Donor Program, visit BeTheMatch.org.