Pre-Clinical Trial on the Co-Transplantation of MSCs and Umbilical Cord Blood Stem Cells.

Objective Cotransplantion of Mesenchymal stem cells(MSCs)with UCB-HSC promote the engraftment, accelerate the recovery of hematopoiesis and alleviate the severity of graft versus host disease(GVHD). Cases and methods 18 cases were treated with UD-UCBT (15 cases) and RD-UCBT (3 cases) .of them, acute lymphoblastic leukemia (high risk) 2 cases, acute myeloblastic leukemia 4 cases, chronic myeloblastic leukemia 3 cases, β-thalassemia major 8 cases and, mucopolysaccharidosis 1 case. HLA matched (6/6) in 3 cases, one locus (5/6) were dismatched in 12 cases and two HLA loci (4/6) in 3 cases. UCB was transfused into recipients according to the regular method. The MSCs were from auto-BM in 3 cases, from allogenic bone marrow of parents 4 cases, from allogenic related bone marrow 10 cases, and cord blood MSCs 1 case. The MSCs were transfused by IV (14 cases) or IBM (4 cases) injection. The conditioning regimens modified on the basis of Bu/CY + Fluda + ATG. GVHD was prevented according to the regular method in our department. Infused NCs dose of UCB was 6.77×10⁷/kg, CD34+ÆÞsG5.58×10⁵/kg; allo-MSCs 4.03×10⁶/kg, auto-MSCs 8.83×10⁶/kg. MSCs origin were detected.

Results

1. Ten cases were full donor engrafted, the time to get ANC ≥0.5×10⁹/L and PLT ≥2.0×10¹⁰/L were on the 13.9^th day and the 30.8^th day.

2. CFU-MIX, MSCs of recipients in Co-transplantation groups recovered gradually from 14^th day to 28^th day.

3. MSCs origin were detected in 4 cases, all were recipients.

Conclusion

1. MSCs co-transplantation accelerated HSCs engraftment and hematopoiesis recovery, the time to get ANC ≥0.5×10⁹/L and PLT ≥2.0×10¹⁰/L were faster than those of single CBT and UD-BMT.

2. MSCs co-transplantation cannot promote engraftment in CBT of β-thalassemia major.

3. Co-transplantation of MSCs accelerated reconstitution of hematopoietic cells and MSCs.