Allogeneic Stem Cell Transplantation

Factors affecting the CD34+ cell yields from the second donations of healthy donors: The steady-state lymphocyte count is a good predictive factor

BACKGROUND

A second allogeneic hematopoietic stem-cell transplantation and donor lymphocyte infusion using cells from the same donor is a therapeutic option in the case of stem-cell graft failure or disease relapse, but little is known about the factors associated with the CD34⁺ cell yields from second donations.

METHODS

One-hundred healthy donors who underwent a second mobilization treatment and peripheral blood stem-cell (PBSC) collection were studied. For both mobilization processes, 5 µg of granulocyte colony-stimulating factor per kg per day was administered. The blood counts of the donors were monitored during the processes.

RESULTS

The second donations from the same donors provided lower apheresis yields than did the initial collections. The number of CD34⁺ cells collected from normal donors after a second cycle of PBSC mobilization was associated with their steady-state lymphocyte counts and the intertransplantation interval. Female sex negatively affected the CD34⁺ cell yields. The cutoff value for the steady-state absolute lymphocyte count was 2.055 × 10⁹/L.

CONCLUSION

To harvest greater numbers of CD34⁺ cells from second collections, male donors and those with intervals of longer than 9 months between donations should be selected. The lymphocyte counts prior to the first donations may predict the content of CD34⁺ cells in the allografts prepared using the second donations.

Unrelated Umbilical Cord Blood Transplant for Children with β-Thalassemia Major

Beta thalassemia major, one of the most prevalent hemoglobinopathy throughout the word, can be cured by allogenic stem cell transplantation (SCT) (Bone Marrow Transplant 36:971-975, 2005). Many patients, however, lack a suitably matched related sibling donor. Unrelated umbilical cord blood (UCB) can be used as an alternative stem cell source for these patients. This report describes SCT for nine children with beta-thalassemia major using partially HLA-matched unrelated UCB. Conditioning included oral busulfan 16 mg/kg (day -10 to -7), cyclophosphamide (Cy) 200 mg/kg (day -5 to -2), fludarabine 90 mg/kg (day -13 to -11), and antithymocyte globulin (rabbit) 7.5 mg/kg (day -3 to -1). The infused cell dose was 10.71 × 10(7)/kg total nucleated cells (TNC) (range 6.5-17 × 10(7)/kg TNC). The patients ranged in age from 1.5 to 7 years, in weight from 10.5 to 17 kg. A second transplant with two unrelated cord blood units was attempted in two patients who had primary graft failure. The retransplant recipients were preconditioned with i.v Cy 120 mg/kg (day -3 to -2). Five of the nine patients engrafted promptly with 50-100 % donor chimerism (56 %). They engrafted at a median of 17 days (range 12-19). One patient is transfusion free for 36 months; a second patient is transfusion free for 18 months and a third is transfusion free for 9 months. There was no transplant related mortality. Four of the nine children had autologous recovery without engraftment. Primary graft rejection is the major complication. Post transplant complications were mild hepatic veno-occlusive disease, acute GVHD grade II, and CMV interstitial pneumonia. The chronic GVHD was limited and could be controlled by Methylprednisolone combined with Mycophenolate. The lack of a marrow donor registry in India makes UCBT from related and unrelated donors a good alternative. Transplant should be delayed until the child is at least 18 months of age. The dose of UCB stem cells is the most important factor for engraftment. UCB has the advantages of rapid availability and low risk of severe GVHD despite donor-recipient HLA disparity (Transplant Proc 37:2667-2669, 2005). We demonstrate the feasibility of this procedure in the setting of a developing country.

Prevalence of chimerism after non-myeloablative hematopoietic stem cell transplantation

CONTEXT AND OBJECTIVE

Non-myeloablative hematopoietic stem cell transplantation (NMA-HSCT) is performed in onco-hematological patients who cannot tolerate ablative conditioning because of older age or comorbidities. This approach does not completely eliminate host cells and initially results in mixed chimerism. Long-term persistence of mixed chimerism results in graft rejection and relapse. Involvement of graft-versus-host disease is concomitant with complete chimerism and graft-versus-tumor effect. The aim of this study was to evaluate the prevalence of chimerism in onco-hematological patients who underwent NMA-HSCT.

DESIGN AND SETTING

Observational clinical study on chimerism status after human leukocyte antigen-identical NMA-HSCT at the Discipline of Hematology and Hemotherapy of Universidade Federal de São Paulo.

METHODS

We sequentially analyzed the amplification of APO-B, D1S80, DxS52, FVW, 33.6, YNZ-2 and H-ras primers using variable number of tandem repeats (VNTR) on 17 pairs and fluorescent in situ hybridization (FISH) with the XY probe and SRY primer on 13 sex-unmatched pairs.

RESULTS

The informativeness of the primers using VNTR was 60% for APO-B, 75% D1S80, 36% DxS52, 14% FVW, 40% YNZ-22 and 16% H-ras. The SRY primer was informative in female receptors with male donors. The XY-FISH method was informative in 100% of the sex-unmatched pairs.

CONCLUSION

These methods were sensitive and informative. In VNTR, the association of APO-B with D1S80 showed 88% informativeness. The quantitative FISH method was more sensitive, but had the disadvantage of only being used for sex-unmatched pairs.

Is a boosting dose of granulocyte-colony-stimulating factor necessary for healthy PBSC donors undergoing secondary apheresis? An institute's experience

Successful allogeneic PBSC transplantation depends upon the infusion of an adequate number of CD34+ cells to patients. Granulocyte-colony-stimulating factors (G-CSF) mobilized PBSC were harvested on 5th day after stimulation from donors. When the CD34+ cell target yield was not achieved; secondary apheresis was performed the following day. Before September 2006, 67 donors (Group A) received five doses of G-CSF. After September 2006, a sixth dose of G-CSF was administered to 35 donors (Group B) to improve CD34+ yield. The mean CD34+-cell concentration of the second PBSC harvest was significantly higher in Group B (1,087 x 10(6)/l vs. 767 x 10(6)/l; P = 0.031).

Strategies for future histocompatible stem cell therapy

Stem cell therapy based on the safe and unlimited self-renewal of human pluripotent stem cells is envisioned for future use in tissue or organ replacement after injury or disease. A gradual decline of regenerative capacity has been documented among the adult stem cell population in some body organs during the aging process. Recent progress in human somatic cell nuclear transfer and inducible pluripotent stem cell technologies has shown that patient-derived nuclei or somatic cells can be reprogrammed in vitro to become pluripotent stem cells, from which the three germ layer lineages can be generated, genetically identical to the recipient. Once differentiation protocols and culture conditions can be defined and optimized, patient-histocompatible pluripotent stem cells could be directed towards virtually every cell type in the human body. Harnessing this capability to enrich for given cells within a developmental lineage, would facilitate the transplantation of organ/tissue-specific adult stem cells or terminally differentiated somatic cells to improve the function of diseased organs or tissues in an individual. Here, we present an overview of various experimental cell therapy technologies based on the use of patient-histocompatible stem cells, the pending issues needed to be dealt with before clinical trials can be initiated, evidence for the loss and/or aging of the stem cell pool and some of the possible uses of human pluripotent stem cell-derivatives aimed at curing disease and improving health.

Transplantation of unrelated donor umbilical cord blood utilizing double-unit grafts for five teenagers with transfusion-dependent thalassemia

To augment graft cell dose, we evaluated the safety of the combined transplantation of two partially HLA-matched umbilical cord blood (UCB) units. Five patients with transfusion-dependent thalassemia, median age 11.1 years (range 10-13.1), received 2 UCB units after myeloablative conditioning. Cord blood units were a 4/6-HLA-match or better with the recipient, and contained a minimum combined pre-freeze CD34 cell dose of 3.0 x 10(5)/kg. All patients engrafted at a median of 15 days (range 12-19). Four patients with durable trilineage engraftment showed acute grade I-III GVHD; none developed extensive chronic GVHD until the date of last contact. The median times to red blood cell transfusion independence and platelet engraftment were 32 and 49 days after transplant, respectively. With a median follow-up of 18.5 months (range 11-32), four patients transplanted with UCB from two different partially HLA-matched donors were transfusion-independent. Therefore, transfusion of two partially HLA-matched UCB units is safe, and may overcome the cell-dose barrier that limits the use of UCB in long-term recipients of multiple transfusions for thalassemia.

Adipose-derived stem and progenitor cells as fillers in plastic and reconstructive surgery

Plastic surgeons are keenly aware of the principle "replace like with like." This principle underlies much of the rationale behind the clinical use of autologous fat transplantation, despite the procedure's drawbacks. Autologous fat transplantation is frequently used for a variety of cosmetic and reconstructive indications not limited to posttraumatic defects of the face and body, involutional disorders such as hemifacial atrophy, sequelae of radiation therapy, and many aesthetic uses such as lip and facial augmentation and wrinkle therapy. However, the limitations of fat transplantation are well known, particularly the long-term unpredictability of volume maintenance. Regenerative cell-based strategies such as those encompassing the use of stem cells hold tremendous promise for augmentation of the soft-tissue space. Preclinical studies and early clinical series show that adipose-derived stem cells offer the possibility of finally fulfilling the key principle of replacing like with like as an aesthetic filler, without the drawbacks of current technology.

Attenuation of murine lysosomal storage disease by allogeneic neonatal bone marrow transplantation using costimulatory blockade and donor lymphocyte infusion without myeloablation

Treatment of nonmalignant childhood disorders by bone marrow transplantation (BMT) is limited by toxicity from preparatory regimens and immune consequences associated with engraftment of allogeneic donor cells. Using costimulatory blockade (anti-CD40L mAb and CTLA-4Ig) combined with high-dose BMT in nonablated neonates, we obtained engraftment and established tolerance using both partially MHC mismatched (H2g7 into H2b) and fully mismatched BM (H2s into H2b). Recipients were mucopolysaccharidosis type VII (MPS VII) mice with lysosomal storage disease in order to assess therapeutic outcome. Recipients treated with donor lymphocyte infusion (DLI) amplified microchimerism to full donor. Recipients without DLI maintained long-term engraftment, tolerance, and had extended life spans. DLI increased donor cell mediated replacement of beta-glucuronidase (GUSB) activity in all tissues and maintained clearance of lysosomes better than in non-DLI-treated mice. DLI amplification of partially mismatched BM and fully mismatched BM caused late onset chronic GvHD in 56% and 100% of recipients, respectively.