How MSK Is Improving Partial Match Stem Cell Transplants

Pedro Lara with his arms in the air

Pedro Lara received a stem cell transplant at MSK in the spring of 2021.

Pedro Lara has lived the American dream. A native of El Salvador, he came to the United States as a young man more than 50 years ago and built a proud life working many jobs in Brooklyn. But when Pedro needed a stem cell transplant after developing non-Hodgkin lymphoma, his ancestry made it difficult to find a fully matched donor.

It’s a growing problem as the population becomes more diverse: Patients of Latin American, Asian, African, Middle Eastern, and mixed ancestry have complex tissue types and may have trouble finding a match if there isn’t one available in their family.

For example, for people of Latin American descent like Pedro, the odds of finding a matched donor in a public registry are less than 50%. For Black patients, the odds are only about 30%.

Infographic text: For people of Latin American, Asian, or Pacific Islander descent, the odds of finding a matched donor in a public registry are less than 50%. For Black patients, the odds are only about 30% versus 80% for white patients.

But researchers at Memorial Sloan Kettering Cancer Center (MSK) have developed several techniques over the past decade that offer hope to these patients by dramatically expanding the universe of potential donors. These days, patients don’t necessarily need a perfect match.

“Our outcomes for transplants using stem cells that are only partially matched are just as successful as for those that use fully matched donors,” says transplant specialist Brian Shaffer, MD. “This is important because about half the people we treat identify as being a racial or ethnic minority.”

“I feel very lucky that MSK opened their doors to me,” says Pedro, now 76. “From my first visit, I felt like God had given me a great opportunity. I truly found my angels.”

MSK Helps Find Donors for Every Patient, No Matter Their Ancestry

To find a suitable match, doctors look for immune markers on white blood cells called HLA types. If two people share all eight markers, they are considered a full match. People with non-European ancestry have more diverse HLA types, which are more difficult to match.

At MSK, even without a fully matched stem cell donor, patients have several options:

  • A family member who is only a half match
  • An unrelated donor who is less than a full match
  • A cord blood transplant, using stem cells collected from umbilical cords

A Half-Match Donor Stem Cell Transplant Offers Pedro the Best Chance of Successful Treatment

Pedro came to MSK after being treated for non-Hodgkin lymphoma at another hospital. The cancer was still present, and the chemotherapy had damaged his bone marrow.

“When Pedro first came to see me, he was getting blood and platelet transfusions every few days. He needed a transplant,” says his doctor, BMT expert Michael Scordo, MD. “Although Pedro was 74, he was in good health. MSK has done extensive research on the best ways to care for older patients who need transplants.”

The next step was finding a donor. Pedro is one of eight siblings, but they were too old to provide healthy cells, even if they were a perfect match. (Ideal donors are under 40.) Pedro has no children and there were no full matches in the public donor databases, either.

MSK has done extensive research on the best ways to care for older patients who need transplants.
Michael Scordo BMT expert

Fortunately, Pedro’s niece in Northern California, Debbie Crystal Lara, then 27, was a half match. “When I learned that I was the best match, of course I was willing to donate my cells,” Debbie says. “It was a blessing to know that I would be able to help my uncle.” The team at MSK and NMDP arranged for Debbie’s cells to be collected at a facility in San Diego. They were quickly frozen and shipped to MSK.

Pedro’s team had a protocol to help make the half-match transplant successful. “With partially matched donors, we give an extra drug for two days after the transplant. This helps prevent the donor’s immune cells from attacking the recipient,” Dr. Scordo says.

Indeed, Pedro had very few complications and recovered quickly. Exactly one month after his transplant, he was discharged from the hospital.

More than two years later, Pedro says he feels great. Now retired from his job as a handyman, he misses working but fills his days in other ways — riding his bike, snuggling with his cat, and teaching his wife to dance.

Pedro says he is grateful for the care he received at MSK, not only from his medical team but also for the emotional, psychological, and financial support — even covering travel costs when his weakened immune system made it dangerous for him to use public transportation.

“Everyone I met throughout my journey gave me the confidence that I would be well again,” he says.