Martin Korbling

Transdifferentiation of human peripheral blood CD34+-enriched cell population into cardiomyocytes, endothelial cells, and smooth muscle cells in vivo.

Background—Adult human peripheral blood cells have been shown to differentiate into mature cells of nonhematopoietic tissues, such as hepatocytes and epithelial cells of the skin and gastrointestinal track. We investigated whether these cells could also transdifferentiate into human cardiomyocytes, mature endothelial cells, and smooth muscle cells in vivo. Methods and Results—Myocardial infarction was created in SCID mice by occluding the left anterior descending coronary artery, after which adult peripheral blood CD34+ cells were injected into the tail vein. Hearts were harvested 2 months after injection and stained for human leukocyte antigen (HLA) and markers for cardiomyocytes, endothelial cells, and smooth muscle cells. Cardiomyocytes, endothelial cells, and smooth muscle cells that bear HLA were identified in the infarct and peri-infarct regions of the mouse hearts. In a separate experiment, CD34+ cells were injected intraventricularly into mice without experimental myocardial infarction. HLA-positive myocytes and smooth muscle cells could only be identified in 1 of these mice killed at different time points. Conclusions—Adult peripheral blood CD34+ cells can transdifferentiate into cardiomyocytes, mature endothelial cells, and smooth muscle cells in vivo. However, transdifferentiation is augmented significantly by local tissue injury. The use of peripheral blood CD34+ cells for cell-based therapy should greatly simplify the procurement of cells for the regeneration of damaged myocardium.

Eight-year experience with allogeneic stem cell transplantation for relapsed follicular lymphoma after nonmyeloablative conditioning with fludarabine, cyclophosphamide, and rituximab

Nonmyeloablative stem cell transplantation in patients with follicular lymphoma has been designed to exploit the graft-versus-lymphoma immunity. The long-term effectiveness and toxicity of this strategy, however, is unknown. In this prospective study, we analyzed our 8-year experience. Patients received a conditioning regimen of fludarabine (30 mg/m(2) daily for 3 days), cyclophosphamide (750 mg/m(2) daily for 3 days), and rituximab (375 mg/m(2) for 1 day plus 1000 mg/m(2) for 3 days). They were then given an infusion of human leukocyte antigen-matched hematopoietic cells from related (n = 45) or unrelated donors (n = 2). Tacrolimus and methotrexate were used for graft-versus-host disease (GVHD) prophylaxis. Forty-seven patients were included. All patients experienced complete remission, with only 2 relapses. With a median follow-up time of 60 months (range, 19-94), the estimated survival and progression-free survival rates were 85% and 83%, respectively. All 18 patients who were tested and had evidence of JH/bcl-2 fusion transcripts in the bone marrow at study entry experienced continuous molecular remission. The incidence of grade 2-IV acute GVHD was 11%. Only 5 patients were still undergoing immunosuppressive therapy at the time of last follow-up. We believe that the described results are a step forward toward developing a curative strategy for recurrent follicular lymphoma.

Clinical toxicity and laboratory effects of granulocyte-colony-stimulating factor (filgrastim) mobilization and blood stem cell apheresis from normal donors, and analysis of charges for the procedures.

BACKGROUND: Apheresis of granulocyte‐colony‐stimulating factor (filgrastim)‐mobilized blood stem cells from normal donors is now being used in place of a marrow harvest in transplantation. How the adverse effects of and charges for this procedure compare with those of the standard marrow harvest is not known.

Fludarabine/melphalan conditioning for allogeneic transplantation in patients with multiple myeloma

The purpose of the study was to determine the feasibility and efficacy of a reduced intensity conditioning regimen of fludarabine and melphalan for allogeneic transplantation in patients with multiple myeloma. From August 1996 to December 2000, 22 patients received a reduced intensity conditioning regimen with fludarabine and melphalan. Median age was 51 years (range, 45–64), median time from initial therapy to transplant was 36 months (range, 3–135 months). Disease phase prior to transplant was primary refractory in two patients, refractory relapse in 11 patients, sensitive relapse in eight patients and initial remission consolidation in one patient. The median number of prior therapies was five (range, 1–7), and median beta 2 microglobulin prior to transplant was 3.0 mg/l (range, 1.0–7.3). All patients received unmanipulated grafts from either HLA matched sibling donors (n = 13) or matched unrelated donors (n = 9). Eighteen patients received fludarabine 30 mg/m2 for 4 days with melphalan 140 mg/m2 as a single dose and four patients received fludarabine 25 mg/m2 for 5 days with melphalan 90 mg/m2 daily for 2 days. All 21 patients evaluable for engraftment achieved a neutrophil count of >0.5 × 109/l after a median of 12 days (range, 9–24), 18 patients achieved platelet transfusion independence after a median of 14 days (range, 8–47). All engrafting patients had 100% donor cell engraftment. Seven patients achieved a complete remission. Six patients are currently alive with a median follow-up of 15 months (range, 10–47 months). The actuarial survival and progression-free survival is 30 ± 11% and 19 ± 9% at 2 years. Non-relapse mortality at 100 days was 19 ± 10% and 40 ± 10% at 1 year. Fludarabine/melphalan combinations are feasible and allow consistent engraftment of allogeneic progenitor cells from both related and unrelated donors in patients with multiple myeloma and should be explored in patients with less advanced disease.

Factors affecting mobilization of CD34+ cells in normal donors treated with filgrastim

BACKGROUND: Multiple days of apheresis are required for some normal peripheral blood progenitor cell (PBPC) donors, to ensure a sufficient collection of CD34+ cells for allografting. It would be of practical value to be able to identify the patients with poor mobilization on the basis of simple pretreatment clinical or hematologic variables.

High Risk of Graft Failure in Patients with Anti-HLA Antibodies Undergoing Haploidentical Stem Cell Transplantation

Background. Although donor-specific anti-human leukocyte antigen (HLA) antibodies (DSA) have been implicated in graft rejection in solid organ transplantation, their role in hematopoietic stem-cell transplantation remains unclear. Methods. To address the hypothesis that the presence of DSA contributes to the development graft failure, we tested 24 consecutive patients for the presence of anti-HLA antibodies determined by a sensitive and specific solid-phase/single-antigen assay. The study included a total of 28 haploidentical transplants, each with 2 to 5 HLA allele mismatches, at a single institution, from September 2005 to August 2008. Results. DSA were detected in five patients (21%). Three of four (75%) patients with DSA before the first transplant failed to engraft, compared with 1 of 20 (5%) without DSA (P=0.008). All four patients who experienced primary graft failure had second haploidentical transplants. One patient developed a second graft failure with persistent high DSA levels, whereas three engrafted, two of them in the absence of DSA. No other known factors that could negatively influence engraftment were associated with the development of graft failure in these patients. Conclusions. These results suggest that donor-specific anti-HLA antibodies are associated with a high rate of graft rejection in patients undergoing haploidentical stem-cell transplantation. Anti-HLA sensitization should be evaluated routinely in hematopoietic stem-cell transplantation with HLA mismatched donors.

Concurrent Administration of High-Dose Rituximab Before and After Autologous Stem-Cell Transplantation for Relapsed Aggressive B-Cell Non-Hodgkin’s Lymphomas

PURPOSE We investigated the efficacy and safety of administering high-dose rituximab (HD-R) in combination with high-dose carmustine, cytarabine, etoposide, and melphalan chemotherapy and autologous stem-cell transplantation (SCT) in patients with recurrent B-cell aggressive non-Hodgkins lymphoma (NHL). PATIENTS AND METHODS Sixty-seven consecutive patients were treated. Rituximab was administered during stem-cell mobilization (1 day before chemotherapy at 375 mg/m(2) and 7 days after chemotherapy at 1,000 mg/m(2)), together with granulocyte colony-stimulating factor 10 mug/kg and granulocyte-macrophage colony-stimulating factor 250 microg/m(2) administered subcutaneously daily. HD-R of 1,000 mg/m(2) was administered again days 1 and 8 after transplantation. The results of this treatment were retrospectively compared with those of a historical control group receiving the same preparative regimen without rituximab. RESULTS With a median follow-up time for the study group of 20 months, the overall survival rate at 2-years was 80% (95% CI, 65% to 89%) for the study group and 53% (95% CI, 34% to 69%) for the control group (P = .002). Disease-free survival was 67% (95% CI, 51% to 79%) for the study group and 43% (95% CI, 26% to 60%) for the control group (P = .004). The median time to recovery of absolute neutrophil count to >/= 500 cells/microL was 11 days (range, 8 to 37 days) for the rituximab group and 10 days (range, 8 to 17 days) for the matched control group (P = .001). However, infections were not significantly increased in patients treated with rituximab. CONCLUSION The results of this study suggest that using HD-R and autologous SCT is a feasible and promising treatment for patients with B-cell aggressive NHL.

Autologous blood stem-cell transplantation in patients with advanced Hodgkin's disease and prior radiation to the pelvic site.

Patients with relapsed Hodgkins disease who respond to salvage therapy are successfully treated with cyclophosphamide, carmustine (BCNU), and etoposide (VP-16) (CBV) followed by autologus bone marrow transplantation (ABMT). Because of heavy pretreatment including radiation to the pelvic site, marrow harvest was not feasible in those patients. We therefore used blood-derived hemopoietic precursor cells as an alternative stem-cell source to rescue them after superdose chemotherapy. Hemopoietic precursor cells were mobilized into the peripheral blood either by chemotherapeutic induction of transient myelosuppression followed by an overshooting of blood stem-cell concentration, or by continuous intravenous (IV) granulocyte-macrophage colony-stimulating factor (GM-CSF) administration. The median time to reach 1,000 WBC per microliter, 500 polymorphonuclear cells (PMN) per microliter, or 20,000 platelets per microliter was 10, 20.5, and 38 days, respectively, for 50% of all patients. The platelet counts of two patients never dropped below 20,000/microL following autologous blood stem-cell transplantation (ABSCT), whereas two other patients had to be supported with platelets for 75 and 86 days posttransplant until a stable peripheral platelet count of 20,000/microL was attained. Among the 11 assessable patients, seven are in unmaintained complete remission (CR) at a median follow-up of 318 days. This is a first report on a series of ABSCTs in patients with advanced Hodgkins disease proving that, despite prior damage to the marrow site, the circulating stem-cell pool is still a sufficient source of hemopoietic precursor cells for stem-cell rescue.

Donor-specific anti-HLA Abs and graft failure in matched unrelated donor hematopoietic stem cell transplantation.

Anti-HLA donor-specific Abs (DSAs) have been reported to be associated with graft failure in mismatched hematopoietic stem cell transplantation; however, their role in the development of graft failure in matched unrelated donor (MUD) transplantation remains unclear. We hypothesize that DSAs against a mismatched HLA-DPB1 locus is associated with graft failure in this setting. The presence of anti-HLA Abs before transplantation was determined prospectively in 592 MUD transplantation recipients using mixed-screen beads in a solid-phase fluorescent assay. DSA identification was performed using single-Ag beads containing the corresponding donors HLA-mismatched Ags. Anti-HLA Abs were detected in 116 patients (19.6%), including 20 patients (3.4%) with anti-DPB1 Abs. Overall, graft failure occurred in 19 of 592 patients (3.2%), including 16 of 584 (2.7%) patients without anti-HLA Abs compared with 3 of 8 (37.5%) patients with DSA (P = .0014). In multivariate analysis, DSAs were the only factor highly associated with graft failure (P = .0001; odds ratio = 21.3). Anti-HLA allosensitization was higher overall in women than in men (30.8% vs 12.1%; P < .0001) and higher in women with 1 (P = .008) and 2 or more pregnancies (P = .0003) than in men. We conclude that the presence of anti-DPB1 DSAs is associated with graft failure in MUD hematopoietic stem cell transplantation.

Twenty-five years of peripheral blood stem cell transplantation

Peripheral blood stem cell transplantation (PBSCT) is the most common transplantation procedure performed in medicine. Its clinical introduction in 1986 replaced BM as a stem-cell source to approximately 100% in the autologous and to approximately 75% in the allogeneic transplantation setting. This historical overview provides a brief insight into the discovery of circulating hematopoietic stem cells in the early 1960s, the development of apheresis technology, the discovery of hematopoietic growth factors and small molecule CXCR4 antagonist for stem- cell mobilization, and in vivo experimental transplantation studies that eventually led to clinical PBSCT. Also mentioned are the controversies surrounding the engraftment potential of circulating stem cells before acceptance as a clinical modality. Clinical trials comparing the outcome of PBSCT with BM transplantation, registry data analyses, and the role of the National Marrow Donor Program (NMDP) in promoting unrelated blood stem-cell donation are addressed.