Dr. Dalal on Graft Failure in Pediatric Non-malignant Disorders

Mansi Dalal, MD, clinical assistant professor, Department of Pediatrics, the University of Florida College of Medicine, discusses findings from a study investigating graft failure risk factors in pediatric patients receiving allogeneic hematopoietic stem cell transplant (HSCT) for non-malignant disorders.

This research aimed to provide contemporary data on risk factors and outcomes associated with graft failure in pediatric patients, for whom little information exists. This study pooled retrospective data from 5 pediatric transplant programs in Florida and included 226 patients between the ages of 1 and 20 years, with a median age of 7 years, who had undergone HSCT for non-malignant disorders, Dalal says. Of these patients, 22 required a second transplant, with 1 patient in this group also needing a third transplant, translating to a graft failure rate of 9.7%, Dalal explains.

The patients who received additional transplants had a lower 2-year survival rate than those who did not require second transplants, at 72% vs 89%, respectively, Dalal notes.

The 3 main risk factors for graft failure identified in this study were HLA mismatched grafts, CMV serology mismatch, and reduced-intensity conditioning regimens, defined as regimens containing cyclophosphamide with or without fludarabine and/or serotherapyinstead of regimens containing busulfan or thiotepa/melphalan/fludarabine, Dalal says. Other risk factors included a Lansky score of 100 and comorbidities.

Alone, none of the identified risk factors were sensitive enough to detect most patients at risk for graft failure. An analysis of risk factor combinations determined that combining HLA mismatch with a Lansky score of 100 identified 20/22 cases of graft failure, evaluating patients with HLA mismatch with no comorbidities identified 20/22 cases, and combining HLA mismatch with CMV mismatch identified 18/22 cases. The combination of HLA mismatch and low- or intermediate-intensity conditioning was the most sensitive of factors associated with a high risk of graft failure, identifying all cases seen in this study population, Dalal concludes.