In this procedure, patients start with chemotherapy that destroys cancer cells in the bloodstream and also removes other blood-forming cells. Blood and bone marrow stem cells are then collected from the donor and injected into the patient to activate the process of rebuilding the immune system.
The procedure is time-consuming and patients are susceptible to infection, often requiring hospitalization for several weeks. After they are discharged from the hospital, they must remain near the transplant center for several more months to ensure their bodies do not reject the transplanted stem cells.
“Due to family obligations, it would have been very difficult for patients to travel out of state,” Ferro said. “We were pleased to be able to offer this treatment and get our first patient home so soon after being discharged from the hospital.”
Until last year, stem cell transplants performed at UNM Cancer Center were autologous.
In an autologous transplant, the patient’s own stem cells are guided into the bloodstream, harvested, and frozen before chemotherapy. After chemotherapy, the stem cells are carefully thawed and injected into the patient’s body, where they travel to the bone marrow to regrow the immune system.
Allogeneic transplants differ from autologous transplants in that the stem cells are taken from a donor. This procedure is used to treat certain blood cancers when autologous transplants are not as helpful.
“By using bone marrow stem cells from a donor, they are not contaminated with leukemia cells, as they would be if they were taken from a patient,” Ferro says. “But the benefits don’t end there. Patients receive an entirely new immune system that attacks tumor cells and helps eradicate any remaining residual disease. This immune response reduces the risk of the disease coming back. It will be done.”
Because the stem cells in allogeneic transplants are not derived from the patient, immune system markers must be carefully tested. Donors are matched according to their immune system’s unique “barcode” in a process called human leukocyte antigen typing or his HLA typing.
HLA typing goes much deeper than standard blood type assessment, identifying the exact HLA markers on our body’s cells from over a million different combinations. Based on these markers, the immune system determines which cells in the body belong to and which cells to fight to stop the infection.
Fero describes another major advance in the field of stem cell transplantation: the ability to use donors who are only half-HLA matched.
“The availability of these haploidentical transplants greatly increases New Mexicans’ ability to access this treatment,” Ferro said. “Brothers or sisters have only a 25% chance of being an exact match, but 50% of siblings and 100% of children and parents are haploidentical.”
Ferro explains that haploidentical transplantation makes treatment possible for many New Mexico patients. Because they are wealthy and have mixed-race ancestry, they may not be able to find a matching donor on the unrelated donor registry.
“We recently completed a haploidentical transplant from a young woman with relapsed leukemia, and we are thrilled with her success,” Ferro said.
Previously, people in New Mexico had to travel out of state and live apart for months if their treatment plan required an allogeneic stem cell transplant. With UNM Cancer Center’s new allogeneic capabilities, you don’t have to.
