Transplants of haploidentical, or half-matched, blood-forming stem cells may be an effective option for patients in need of a transplant without a fully matched donor; however, in the past, in comparison to transplant from a fully matched donor, this treatment has been associated with an increased risk of infection and disease recurrence.

This study tested the effectiveness of manipulating in the lab these half-matched donor stem cells.

In this process, the team selectively removed the alpha/beta-positive T cells and CD19-positive B cells from the donor graft, as those are more likely to trigger donor cells to attack recipient cells, resulting in a dangerous complication known as graft-versus-host disease (GVHD).

At the same time, the process preserved healthy, mature, immune-active cells known as natural killer and gamma/delta-positive T cells that help prevent disease relapse and protect against infection. A total of 45 patients with acute leukaemia were treated with genetically engineered stem cells from one of their parents.

Transplants engrafted in 44 of the 45 patients, with a 29 percent cumulative incidence of mild GVHD. One month after transplant, follow-up analyses showed that transplanted cells had persisted in the patients and demonstrated potential anti-leukaemic activity, which continued to increase over time.

“Our results, which demonstrate that transplantation of selectively modified, half-matched donor stem cells boasts success rates equivalent to those of a fully matched transplant, preventing GVHD and reducing transplant-related death, help continue to establish this approach as a viable option for patients without a matched donor,” said study author Alice Bertaina, MD, of the Bambino Gesu Children’s Hospital in Rome, Italy.

“This has the potential to make this lifesaving treatment more accessible to a much larger population of patients who may not have a perfect donor match.”

Source: ASH