Mesenchymal Stem Cells Promising for Severe GVHD

• ORLANDO—Infusion of bone-marrow-derived mesenchymal stem cells (MSCs) appears to be a promising treatment for severe, steroid-resistant graft-vs-host disease (GVHD), Katarina Le Blanc, MD, PhD, of Karolinska University Hospital Huddinge, Stockholm, said at the American Society of Hematology 48th Annual Meeting (abstract 753).

Mesenchymal stem cells from adult bone marrow have the capacity to differentiate into several mesenchymal tissues and also appear to have immunomodulatory and anti-inflammatory effects, and have been shown to inhibit T-cell alloreactivity in vitro. Dr. Le Blanc and colleagues from the European Blood and Marrow Transplantation group transfused MSCs into the gut and liver of a 9-year-old boy with steroid-refractory GVHD. "We saw a remarkable effect, in terms of reduced inflammation in the GI tract and very rapid recovery of the intestinal epithelium," she said. As a result, she and other European researchers formed an MSC expansion consortium.

She presented data from 52 patients with grade 3-4 acute gastrointestinal GVHD following hematopoietic stem cell transplant for leukemia. MSCs were harvested from HLA-identical siblings, haploidentical donors, and HLA-mismatched donors. Overall, 35 patients (68%) responded. Early treatment was better than later treatment, and children responded slightly better than adults. Twenty-two patients are alive at 6 weeks to 3.5 years after transplant; half of these have no GVHD, and the rest have a chronic form. Seventeen nonresponders died from GVHD; eight severely immunocompromised patients died from infection. Four other deaths were not GVHD related, and one patient was lost to follow-up.