[Show abstract][Hide abstract] ABSTRACT: CD34-selected haploidentical and unrelated donor allogeneic stem cell transplantation (AlloSCT) in paediatric recipients is associated with sustained engraftment and low risk of acute graft-versus-host disease (aGVHD), but limited by delayed immune reconstitution and increased risk of viral and fungal infection. The optimal dose of donor T cells to prevent graft failure and minimize risk of early opportunistic infection and post-transplant lymphoproliferative disorder (PTLD), while avoiding severe aGVHD, remains unknown. We prospectively studied CD34-selected 8-10/10 human leucocyte antigen (HLA)-matched unrelated donor (MUD) peripheral blood stem cell transplantation (PBSCT) in a cohort of 19 paediatric AlloSCT recipients with malignant (n = 13) or non-malignant (n = 6) diseases. T cells were added back to achieve total dose 1·0-2·5 × 10(5) CD3(+) /kg. GVHD pharmacoprophylaxis consisted only of tacrolimus. All patients engrafted neutrophils. Probabilities of grade II-IV aGVHD, limited chronic GVHD (cGVHD), and extensive cGVHD were 15·8%, 23·3%, and 0%, respectively. One patient developed PTLD. One-year infection-related mortality was 5·6%. T cell immune reconstitution was delayed. One-year overall survival was 82·3%. Five patients with malignant disease ultimately died from progressive disease. CD34-selected MUD PBSCT using a defined dose of T cell add-back resulted in high rates of engraftment and low risk of grade II-IV aGVHD, early transplantation-related mortality, and extensive cGVHD.
British Journal of Haematology 02/2012; 157(2):205-19. · 4.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The amount of acid citrate dextrose formula A (ACD-A), which is a commonly used anticoagulant in leukopheresis, has to ensure both the safety of the donor and guarantee the integrity of the peripheral blood stem cell (PBSC) product until its transplant. Two recent consecutive cases of postthaw PBSC product clotting initiated a look-back investigation of the ACD-A percentage in leukopheresis products collected in our facility. The data indicated a significant difference between the average amount of ACD-A in prefreezing products collected during 2006 (11.4%) and in products collected during 2007 and 2008 (8.8% and 8.7%, respectively). These findings and the fact that the two clotted products had less than 7% ACD-A indicated that insufficient amount of anticoagulant might contribute to their clotting. This investigation prompted us to modify our collection and thawing procedures to prevent similar events in the future.
Journal of Clinical Apheresis 11/2009; 24(6):265-8. · 2.27 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The acceptable dose of haematopoietic progenitor cells (HPCs) for transplantation is generally based on the number of CD34+ cells determined prior to cryopreservation. Commonly, cryopreservation is associated with total nucleated cell viability loss. Because HPCs have been shown to be more resistant to cryopreservation damage than nucleated cells overall, low viability may not reflect the quality and integrity of the thawed product.
Peripheral blood HPC products from 45 mobilized allogeneic and autologous donors were harvested by continuous flow blood separation and cryopreserved in 7.5% dimethyl sulfoxide. The number of viable CD34+ cells was determined by flow cytometry. Viability was measured by trypan blue (TB) uptake and 7-aminoactinomycin D (7-AAD) flow cytometry.
Post-thaw HPC products were analysed for viability, CD34+ cell recovery and engraftment capability. The average post-thaw viable CD34+ cell recovery was 86.4%, while the average post-thaw viability, measured by TB or 7-AAD, was 74.0% and 57.0%, respectively. Most of the cells that did not survive cryopreservation were of the granulocyte series. All of the donors who underwent transplantation engrafted, mostly within 14 days.
Our data show that most CD34+ cells survive cryopreservation, regardless of the overall post-thaw total nucleated cell viability. Measuring the number of viable CD34 cells post-thaw might be of importance, and in cases of low viability can confirm the quality of the product issued.
[Show abstract][Hide abstract] ABSTRACT: Hematopoietic stem cell (HSC) transplants are widely used to treat patients with cancer and other disorders of the blood and immune system. The isolation of human HSC offers the promise for obtaining a remarkable variety of new therapeutics. Thus, an effort to analyze and assess the safety of these cells is extremely important. As with blood transfusion, microbial infections have been transmitted by HSC transplantation. Due to the inability to sterilize HSC and the immunodeficient nature of their recipients, the risk of infectious disease transmission remains a major concern. Assessing HSC safety requires careful monitoring of their collection, manipulation, and distribution. This review describes the pathogens that are recovered from HSC products, and the approaches available for detecting microbial contamination in HSC products prior to transplant.
Reviews in Medical Microbiology 03/2007; 18(2):17-27. · 0.36 Impact Factor