A successful haploidentical bone marrow transplantation method in rabbits: perfusion method plus intra-bone marrow-bone marrow transplantation

Optimization of intrabone delivery of hematopoietic progenitor cells in a swine model using cell radiolabeling with [89]zirconium

Intrabone (IB) hematopoietic cell transplantation (HCT) of umbilical cord blood in humans remains experimental and the technique has not been optimized. It is unknown whether hematopoietic progenitor cells (HPCs) injected IB are initially retained in the marrow or rapidly enter into the venous circulation before homing to the marrow. To develop an IB-injection technique that maximizes HPC marrow-retention, we tracked radiolabeled human HPCs following IB-injection into swine. We developed a method to radionuclide-label HPCs using a long-lived positron emitter (89) Zr and protamine sulfate that resulted in cellular-retention of low-dose radioactivity. This approach achieved radioactivity levels sufficient for detection by positron emission tomography with both high sensitivity and spatial resolution when fused with computed tomography. We found that conditions utilized in pilot IB-HCT clinical trials conducted by others led to both rapid drainage into the central venous circulation and cellular extravasation into surrounding muscle and soft tissues. By optimizing the needle design, using continuous real-time intra-marrow pressure monitoring, and by reducing the infusion-volume and infusion-rate, we overcame this limitation and achieved high retention of HPCs in the marrow. This method of IB cellular delivery is readily applicable in the clinic and could be utilized in future investigational IB-HCT trials aimed at maximizing marrow retention of HPCs.

Perfusion method for bone marrow cell collection in poor mobilizer lymphoma patient

We previously described a unique procedure for the collection of bone marrow cells (BMCs) using a perfusion method (PM). In cynomolgus monkeys, this method resulted in lower contamination with T cells (<10%). Here, we performed PM on a poor mobilizer lymphoma patient. We confirmed the safety of the intra-bone marrow injection of saline to collect the BMCs. The collected BMCs showed minimal contamination with T cells (<15%) and red blood cells (RBCs) (<4%) from the peripheral blood. It took a total of only 30 min to collect the BMCs. Moreover, transfusion of RBCs was unnecessary. There were no relevant post-operative side effects except for self-limiting pain at the sites of collection, and the patient was able to walk around the hospital after the operation.