Treatment of Intractable Graft-Versus-Host Disease with Bone Marrow Derived Mesenchymal Stem Cells - A Pilot Clinical Trial.

Recent studies have shown that mesenchymal stem cells (MSCs) have profound immunomodulatory function, both in vitro and in vivo. There are several reports to treat effectively therapy-resistant graft-versus-host disease (GVHD) using ex vivo expanded MSCs. We performed a pilot clinical trial to treat intractable GVHD with bone marrow derived MSCs. All of 5 patients, 3 males and 2 females, with steroid-refractory GVHD were included in this study. Age range was 27 to 48 years old. Diagnosis of underlying disease was CML in 2, AML in 1, ALL in 1, and MDS in 1. Hematopoietic stem cell (HSC) donor was a sibling in 2 and an unrelated volunteer in 3. The donor of MSCs was a sibling in all patients: two donors were the same to HSC donors, but other three were not. About 20 mL of bone marrow was aspirated from donors and MSCs were cultured ex vivo. After about 3 weeks, MSCs were harvested for the first infusion, and 4 more weeks’ culture was done for the planned second infusion. The infused doses of MSCs were 5.3 to 6.9 x 10⁶/kg for the first infusion and 1.8 to 7.0 x 10⁶/kg for the second infusion. The onset of GVHD was post-transplant day 24 to 191 and the times from the onset of GVHD to the infusion of MSCs were 73 to 2469 days. There were no adverse events related to the infusion of MSCs. Three patients did not show any response to the treatment of MSCs for GVHD and two showed minimal response: transient improvement of jaundice and diarrhea without improvement of skin GVHD lesions in one patient, and improvement of performance status without significant increase of pulmonary function test parameters in another patient with lung involvement of GVHD. There were no significant changes in hemoglobin, and peripheral blood counts of platelets, leukocytes, lymphocytes, CD3+ cells, CD4+ cells, CD8+ cells, NK cells and B cells over 6 months’ period after the infusion of MSCs. Results of our pilot study suggest that the treatment effects of MSCs may be limited in patients with chronic established GVHD. Further studies on MSCs for GVHD should be focused on acute or exacerbated GVHD.