Abstract 18: A Case of Successful Poor Graft Function Treatment with Wharton Jelly Mesenchymal Stem Cells

Abstract Introduction Poor graft function (PGF) is a life-threatening complication that occurs after hematopoietic stem cell transplantation (HSCT). This is persistent neutropenia/thrombocytopenia, with complete donor chimerism, lack of severe GVHD or relapse, during the first 12 months after HSCT. Objectives To present a case study of PGF treatment with Wharton jelly (WJ) mesenchymal stem cells (MSC). Methods A 16-year-old boy was performed allogeneic bone marrow HSCT from a fully matched family donor due to secondary myelodysplastic syndrome, diagnosed 4 years after treatment of pineablastoma. Engraftment was documented on day +28 (95%) and 99% on day +42. The patient was discharged home in good general condition on day +37 post-transplant. From day +54, a deterioration of blood count parameters was observed. Partial secondary graft failure was diagnosed and no hematological response was achieved with 4 planned doses of Rituximab. Secondary causes of bone marrow failure and cytopenias were excluded. A bone marrow biopsy showed absence of the primary disease but significantly reduced bone marrow cellularity. Finally PGF was diagnosed and the patient was re-transplanted HSC from the same donor, without conditioning with prior administration of WJ MSCs (obtained from FamiCord Group) in the number of 120 x 106. No post-transplantation immunosuppression was used. Results As a result of the procedure, the blood count parameters increased and stabilized at a level that no longer required additional transfusions support. No adverse effects and no early and late post-tranplant complications were observed. Currently, the patient remains in good general condition. Due to hemochromatosis previously caused by numerous red blood cells transfusions, he requires chelation therapy. Administration of MSCs is a safe method and might by an effective therapy for patients with PGF. Discussion Our clinical case is consistent with several literary reports showing efficacy of third parties MSCs in the treatment of PGF. The mechanism of therapeutic effect of MSCs in PGF is poorly known, it may be hypothesized that MSCs modulate bone marrow microenvironment and exert pracrine regenerative effect.