Placenta‐Derived Decidua Stromal Cells for Treatment of Severe Acute Graft‐Versus‐Host Disease

Severe acute graft-versus-host disease (GVHD) is a life-threatening complication after allogeneic hematopoietic stem cell transplantation (HSCT). The placenta protects the fetus from the mother's immune system. We evaluated placenta-derived decidua stromal cells (DSCs), which differ from bone marrow mesenchymal stromal cells (BM-MSCs), as a treatment for severe acute GVHD. DSCs were obtained from term placentas. The DSCs were given to 38 patients with severe acute GVHD; 25 were steroid refractory (SR). DSCs were thawed and infused in buffer supplemented with either 10% AB plasma (group 1, n = 17), or 5% albumin (group 2, n = 21). The viability of cells was higher when thawed in albumin rather than AB plasma (p < .001). Group 1 received a higher cell dose (p < .001), cells of lower passage number (p < .001), and fewer infusions (p = .002) than group 2. The GVHD response (no/partial/complete) was 7/5/5 in group 1 and 0/10/11 in group 2 (p = .01). One-year survival in the two groups was 47% (95% confidence interval [CI] 23-68) and 76% (95% CI 51-89), respectively (p = .016). For the SR patients, 1-year survival was 73% (95% CI 37-90) in SR group 2 (n = 11), which was better than 31% (95% CI 11-54) in SR group 1 (n = 13; p = .02), 20% (95% CI 5-42) in BM-MSC treated (n = 15; p = .0015), and 3% (95% CI 0-14) in historic controls (n = 32; p < .001). DSCs are a promising new treatment for severe acute GVHD. Prospective randomized trials are needed for evaluation of efficacy. (Clinical trial NCT-02172937.) Stem Cells Translational Medicine 2018;7:325-332.