Comparing patient outcomes for different sources of stem cells

This study compared three sources of stem cells for patients receiving allogenic stem cell transplantation. The authors suggested that stem cells from familial haploidentical donors can lead to better patient outcomes.

Hodgkin lymphoma (HL) is generally considered curable. However, some cases do not respond to first-line therapy. This is known as refractory HL, and can be treated with stem cell transplantations. Stem cell donors that are a perfect genetic match are difficult to find, so partially matched donors may be used.

Previous studies have found three possible sources for these partially matched donors: haploidentical familial donors (HAPLO, those that are a 50% match), mismatched unrelated donors (MMUD), and cord blood (CB, stem cells from umbilical cords). The three sources of stem cells have not been directly compared in previous studies.

This study compared the outcomes of patients who received stem cells from HAPLO donors, MMUD, or CB donors. The medical records of 98 patients were reviewed. 34 patients received stem cells from HAPLO donors. 37 patients received stem cells from MMUD donors. 27 patients received stem cells from CB. All patients were treated with lower intensity conditioning (chemotherapy) before transplantation. The chemotherapy combinations and doses differed among the patients. All patients were treated with cyclophosphamide (Cytoxan) after transplantation to prevent graft-versus-host disease (GVHD; a condition where the donor cells attack the healthy cells of the patient). The average length of follow up for all patients was 31 months.

There were no significant differences in survival or time to disease progression between the groups.

After 2 years, 15% of patients in the HAPLO group experienced chronic GVHD. 48% of patients in the MMUD group and 39% of patients in the CB group experienced chronic GVHD.

Patients in the HAPLO group had significantly higher GVHD-free, relapse-free survival rates (time without relapse or GVHD). Compared with patients in the HAPLO group, MMUD patients were 2.02 times more likely to experience GVHD. CB donor patients were 2.43 times more likely to experience GVHD. 

The study concluded that patients undergoing reduced intensity conditioning before receiving stem cells from haploidentical familial donors were less likely to get graft versus host disease compared to other sources.