Association of CD34 cell dose with hematopoietic recovery, infections, and other outcomes after HLA-identical sibling bone marrow transplantation

Association of bone marrow natural killer cell dose with neutrophil recovery and chronic graft-versus-host disease after HLA identical sibling bone marrow transplants

Allogeneic bone marrow (BM) transplant (BMT) outcomes have been correlated with the infused nucleated, CD34(+), and T- cell dose. The potential impact of natural killer (NK) BM infused cell dose has however not been established. We analysed the outcomes of 78 patients receiving an HLA identical BMT. A higher NK cell dose was associated with the speed of neutrophil (P = 0.05) and platelet recovery (P = 0.04). Higher nucleated cells, CD34(+), CD3(+), CD3(+)/4(+), CD3(+)/8(+) and NK cell dose were associated with a lower incidence of chronic GvHD (cGvHD) in univariate analysis. In multivariate analysis, the risk of cGvHD was increased by a lower NK cell dose [hazard ratio (HR) = 2.3 (1.2-4.4) for cell dose <0.9 x 10(6)/kg; P = 0.01] and an older age [HR = 1.4 /10 years (1.1-1.8); P = 0.002]. In addition, a higher CD3(+)/4(+) and NK cell dose were associated with a decreased incidence of viral infections (P = 0.03 and P = 0.06 respectively). No specific cell subpopulation infused dose was associated with survival. In conclusion, a higher BM NK cell dose is associated with an increased speed of neutrophil recovery and a decreased incidence of cGvHD.

Risk assessment in haematopoietic stem cell transplantation: Stem cell source

Bone marrow (BM) has been used for many years as the unique source of progenitor cells for allogeneic transplantation. However, two other sources of progenitor cells, peripheral blood (PB) and umbilical cord (UC), are being increasingly used. The type of graft is one of the most important factors in determining the speed and robustness of the reconstitution after the transplant of monocytes, T lymphocytes, B lymphocytes, NK cells, and dendritic cells. This fact is of especial relevance since the most important reactions after allogeneic transplants - e.g. graft-versus-host disease (GVHD), graft-versus-leukaemia effect (GvL), achievement of full donor chimerism, and fight against infections - are strongly influenced by a rapid and robust reconstitution of these cells. For this reason, the choice of the type of graft for allogeneic transplantation will influence the clinical outcome.

The Graft Content of Donor T Cells Expressing γδTCR+ and CD4+foxp3+ Predicts the Risk of Acute Graft versus Host Disease after Transplantation of Allogeneic Peripheral Blood Stem Cells from Unrelated Donors

PURPOSE

Recently, high numbers of regulatory T cells within the stem cell graft were described to be associated with less graft-versus-host disease (GVHD) after related peripheral blood stem cell transplantation (PBSCT). Studies in mice also suggest a distinct role of gamma delta TCR(+) T cells in mediating GVHD. Therefore, the aim of this study was to define the yet-unknown role of regulatory and gamma delta TCR(+) T cells in human PBSCT from unrelated donors.

EXPERIMENTAL DESIGN

The frequency of both T-cell subsets within the graft was analyzed in 63 patients receiving unrelated allogeneic PBSCT. The respective amounts were quantified by flow cytometry and PCR and further correlated with clinical outcome.

RESULTS

The grafts contained a median of 11.2 x 10(6)/kg CD4(+)foxp3(+) and 9.8 x 10(6)/kg gamma delta TCR(+) T cells, respectively. Patients receiving more CD4(+)foxp3(+) cells had a lower cumulative incidence of acute GVHD II-IV (44% versus 65%, P=0.03). Interestingly, in patients who received higher concentrations of donor gamma delta TCR(+) T cells, acute GVHD II-IV was more frequent (66% versus 40%, P=0.02). In multivariate analysis, only the graft concentration of gamma delta TCR(+) T cells (P=0.002) and a positive cytomegalovirus status of the recipient (P = 0.03) were significantly associated with the occurrence of acute GVHD II-IV.

CONCLUSION

Graft composition of T-cell subsets seems to affect the outcome of patients receiving allogeneic PBSCT from unrelated donors. Therefore, selective manipulation or add-back of particular subsets might be a promising strategy to reduce the incidence of GVHD.

Phenotypic and Functional Analysis of Human Fetal Liver Hematopoietic Stem Cells in Culture

Steady-state hematopoiesis and hematopoietic transplantation rely on the unique potential of stem cells to undergo both self-renewal and multilineage differentiation. Fetal liver (FL) represents a promising alternative source of hematopoietic stem cells (HSCs), but limited by the total cell number obtained in a typical harvest. We reported that human FL nonobese diabetic/severe combined immunodeficient (NOD/SCID) repopulating cells (SRCs) could be expanded under simple stroma-free culture conditions. Here, we sought to further characterize FL HSC/SRCs phenotypically and functionally before and following culture. Unexpanded or cultured FL cell suspensions were separated into various subpopulations. These were tested for long-term culture potential and for in vivo repopulating function following transplantation into NOD/SCID mice. We found that upon culture of human FL cells, a tight association between classical stem cell phenotypes, such as CD34(+) /CD38(-) and/or side population, and NOD/SCID repopulating function was lost, as observed with other sources. Although SRC activity before and following culture consistently correlated with the presence of a CD34(+) cell population, we provide evidence that, contrary to umbilical cord blood and adult sources, stem cells present in both CD34(+) and CD34(-) FL populations can sustain long-term hematopoietic cultures. Furthermore, upon additional culture, CD34-depleted cell suspensions, devoid of SRCs, regenerated a population of CD34(+) cells possessing SRC function. Our studies suggest that compared to neonatal and adult sources, the phenotypical characteristics of putative human FL HSCs may be less strictly defined, and reinforce the accumulated evidence that human FL represents a unique, valuable alternative and highly proliferative source of HSCs for clinical applications.

Mobilizing stem cells from normal donors: is it possible to improve upon G-CSF?

Currently, granulocyte colony stimulating factor (G-CSF) remains the standard mobilizing agent for peripheral blood stem cell (PBSC) donors, allowing the safe collection of adequate PBSCs from the vast majority of donors. However, G-CSF mobilization can be associated with some significant side effects and requires a multi-day dosing regimen. The other cytokine approved for stem cell mobilization, granulocyte-macrophage colony stimulating factor (GM-CSF), alters graft composition and may reduce the development of graft-versus-host disease, but a significant minority of donors fails to provide sufficient CD34+ cells with GM-CSF and some experience unacceptable toxicity. AMD3100 is a promising new mobilizing agent, which may have several advantages over G-CSF for donor mobilization. As it is a direct antagonist of the interaction between the chemokine stromal-derived factor-1 and its receptor CXCR4, AMD3100 mobilizes PBSCs within hours rather than days. It is also well tolerated, with no significant side effects reported in any of the clinical trials to date. Studies of autologous and allogeneic transplantation of AMD3100 mobilized grafts have demonstrated prompt and stable engraftment. Here, we review the current state of stem cell mobilization in normal donors and discuss novel strategies for donor stem cell mobilization.

Quantification of nucleated red blood cells in allogeneic marrow graft and impact of processing on recovery

BACKGROUND

In allogeneic bone marrow transplantation (BMT), a higher nucleated and CD34+ cell dose has been reported to improve various outcomes. Other cell types, such as lymphocyte subsets, also influenced BMT results. While nucleated red blood cells (NRBCs) represent a subset of bone marrow (BM) cell subpopulation, the question of their quantification in BM grafts and the impact of BM processing on their recovery has not been addressed.

STUDY DESIGN AND METHODS

In a prospective study on 77 BM products, NRBCs were enumerated by flow cytometry and the recovery analyzed after manipulation. Because NRBCs could compromise white blood cell count, the impact of NRBC count on CD34+ cell percentage and total nucleated cell (TNC) dose were also determined.

RESULTS

The mean percentage of NRBCs in BM grafts was 21.6 percent (range, 7.8%-40.9%). Mean NRBC recoveries after BM concentration or RBC depletion were 98.4 and 28.7 percent, respectively, close to those obtained for TNC cells (88.6 and 31.3%, respectively). When corrected with NRBC count, the mean percentages of corrected CD34+ cell and TNC dose were significantly modified when compared with uncorrected values, whatever the type of BM manipulation.

CONCLUSION

Our data show that NRBC quantification might be of importance to improve quality control of BM products and to evaluate the influence of NRBCs cell dose on outcomes after BMT.

Results of genoidentical hemopoietic stem cell transplantation with reduced intensity conditioning for acute myelocytic leukemia: higher doses of stem cells infused benefit patients receiving transplants in second remission or beyond--the Acute Leukemia Working Party of the European Cooperative Group for Blood and Marrow Transplantation

PURPOSE

Nucleated cell dose is an important and modifiable factor in hematopoietic stem cell transplantation (HSCT), however its association with outcomes in the context of reduced intensity conditioning regimen (RIC) HSCT for adults with acute myelocytic leukemia (AML) is not known.

PATIENTS AND METHODS

From 1998 to 2003, 253 patients with de novo AML, received transplants with RIC and peripheral blood from a genoidentical donor. Median age was 55 years (range, 18 to 72) and the median follow-up was 17 months (range, 2 to 67). One hundred forty one patients received transplants in first remission (CR1), 47 received transplants in second remission (CR2), and 65 patients received transplants in a more advanced phase. Fludarabin-based RIC was used in 91% of patients and low-dose (< 4 Gy) total-body radiation in 23% of patients. The median nucleated and CD34 cell dose infused were 9.1x 10(8)/kg and 5.8x 10(6)/kg, respectively.

RESULTS

Overall, 2-year leukemia-free survival (LFS) was 41% +/- 4% and it was 46% +/- 5% for patients receiving a higher cell dose (> 9.1x 10(8)/kg) and 37% +/- 5% for the remainders (P = .03). Higher cell doses exclusively benefited patients who received transplantations in CR2 or beyond, with LFS of 47 +/- 8 versus 20 +/- 8, with no detectable effect for patients who received transplants in CR1. In a multivariate analysis of the overall patient population, higher nucleated cell dose cells were associated with higher LFS (P = .04), higher incidence of chronic graft-versus-host disease (P = .01), and there was a trend towards a lower relapse incidence (P = .06). Interestingly, CD34+ cell dose was not associated with any outcomes.

CONCLUSION

Nucleated cell dose is an important factor that can be modified to improve results of RIC for patients with AML transplanted later than in CR1.

ABO-mismatched marrow processing for transplantation: results of 114 procedures and analysis of immediate adverse events and hematopoietic recovery

BACKGROUND

Red cell (RBC) depletion is needed to bypass ABO mismatch in allogeneic bone marrow transplantation (BMT). Technical and clinical data obtained after bone marrow (BM) processing with a continuous-flow cell separator (Cobe Spectra, Gambro BCT) are reported.

STUDY DESIGN AND METHODS

RBC depletion and recovery of nucleated cells, CD3+ cells, CD34+ cells, and colony-forming unit-granulocyte-macrophage were calculated. Bacteriologic contaminations, side effects of graft infusion, and hematopoietic recovery were analyzed.

RESULTS

A total of 114 BM samples were processed. The mean volume collected was 1099 mL (range, 390-2450 mL). Initial and residual mean RBCs volumes were 309.9 and 4.0 mL corresponding to a depletion of 98.6 +/- 0.78 percent. Before processing, the mean numbers of nucleated cells, granulocytes, CD3+ cells, CD34+ cells, and CFU-GM were 20.28 x 10(9), 12.79 x 10(9), 1.96 x 10(9), 356.7 x 10(6), and 195.6 x 10(5), respectively. The mean corresponding recoveries after processing were 33.66, 48.98, 82.02, 82.2, and 93.9 percent. Limited side effects were observed in 14 patients without correlation with residual RBCs volume. All but two patients engrafted.

CONCLUSION

BM processing with the Cobe Spectra cell separator provides high rates of RBC depletion without significant side effects after BMT.

Hematopoietic stem cell transplantation for 30 patients with primary immunodeficiency diseases: 20 years experience of a single team

We retrospectively analyzed our results of 30 patients with three distinctive primary immunodeficiency diseases (PIDs)--severe combined immunodeficiency (SCID, n = 11), Wiskott-Aldrich syndrome (WAS, n = 11) and X-linked hyper-immunoglobulin M (IgM) syndrome (XHIM, n = 8)--who underwent hematopoietic SCT (HSCT) during the past 20 years. Until 1995, all donors were HLA-haploidentical relatives with T-cell depletion (TCD) (n = 8). Since 1996, the donors have been HLA-matched related donors (MRD) (n = 8), unrelated BM (UR-BM) (n = 7) and unrelated cord blood (UR-CB) (n = 7). Twenty-seven of 30 patients had various pre-existing infections with or without organ damages before HSCT. Conditioning regimen and GVHD prophylaxis were determined according to disease, donor and pretransplant status. Although one of eight patients transplanted with TCD is alive with full engraftment, the other seven died. On the other hand, 18 of 22 patients transplanted without TCD are alive and well, including six of eight transplanted from MRD, seven of seven from UR-BM and five of seven from UR-CB. All 19 survivors did not require Ig supplementation after HSCT. These results indicate that UR-CBT as well as UR-BMT provides good results for PID comparable to MRD-SCT, and that early diagnosis, HSCT at early stage, careful supportive therapy and monitoring for various pathogens are important for the successful HSCT.

Marrow aplasia developing 13 years after HLA-identical sibling allogeneic transplantation for chronic myeloid leukaemia: successful treatment with antithymocyte globulin and peripheral blood stem cell infusion from the original donor

Secondary or late graft failure has been defined as the development of inadequate marrow function after initial engraftment has been achieved. We describe a case of profound marrow aplasia occurring 13 years after sibling allogeneic bone marrow transplantation for chronic myeloid leukaemia (CML) in first chronic phase. Although the patient remained a complete donor chimera, thereby suggesting that an unselected infusion of donor peripheral blood stem cells (PBSC) or bone marrow might be indicated, the newly acquired aplasia was thought to be immune in aetiology and some immunosuppression was therefore considered appropriate. Rapid haematological recovery was achieved after the infusion of unselected PBSC from the original donor following conditioning with anti-thymocyte globulin (ATG).

Evidence that donor intrinsic response to G-CSF is the best predictor of acute graft-vs-host disease following allogeneic peripheral blood stem cell transplantation

OBJECTIVE

Risk factors of acute graft-vs-host disease (GVHD) following allogeneic bone marrow transplantation have been well described before. In this study, we tested the hypothesis that acute GVHD after allogeneic peripheral blood stem cell (PBSC) transplant might be associated with donors' responsiveness to granulocyte colony-stimulating factor (G-CSF), rather than the dose of CD34(+) cells infused.

PATIENTS AND METHODS

We retrospectively analyzed mobilization and transplant data (demographic characteristics, donor blood cell subsets after G-CSF, graft composition) in 149 consecutive HLA-identical donor/recipient pairs in order to identify acute GVHD risk factors.

RESULTS

In 25% of donors, G-CSF mobilization led to an outstanding response, defined as greater than 117 x 10(6) CD34(+) cells/L. Overall, incidence of grades II-IV acute GVHD was 20.1% (95% CI: 16.6-23.6). Following univariate analysis, the incidence increased significantly in recipients receiving greater than 10 x 10(6) CD34(+) cells/kg (35% vs 15%; p = 0.007), and those transplanted from outstanding mobilizers (41% vs 12%, p < 0.0001). In multivariate analysis, only transplantation from outstanding mobilizers remained significant (p = 0.02). Donor or recipient demographic characteristics and lymphocyte subsets reinfused in the graft had no impact.

CONCLUSIONS

We demonstrate for the first time that donor responsiveness to G-CSF is associated with acute GVHD following PBSC transplantation. If confirmed, this correlation will help to identify recipients who could potentially benefit from improved prophylaxis. As further corollary, decreasing the dose of CD34(+) cells infused is unlikely to prevent acute GVHD. Future studies should focus on the molecular bases of interindividual discrepancies in response to G-CSF.

Influence of telomere length on short-term recovery after allogeneic stem cell transplantation

OBJECTIVE

Telomeres shorten in somatic cells during aging and states of increased turnover, including hematopoietic stem cell transplantation. Fast hematopoietic recovery is critical for the patients' course after hematopoietic stem cell transplantation. It is unknown whether telomere length in hematopoietic stem cells (HSCs) predicts short-term hematopoietic recovery.

METHODS

We quantified telomere length by flow fluorescence in situ hybridization analysis in HSCs and granulocytes of healthy stem cell donors and monitored time to peripheral blood cell recovery in transplanted hosts. Furthermore, we measured in vitro repopulation potency of HSCs by assaying for colony-forming units granulocyte-macrophage (CFU-GM).

RESULTS

Telomere length in HSC shortens continuously in vivo and is comparable to telomere length in granulocytes from the same individual. Numbers of in vitro formed CFU-GM per HSC show an inverse relationship to age and telomere length. However, telomere length in HSCs was not correlated with short-term recovery after HSC transplantation.

CONCLUSION

These findings suggest that healthy stem cell donors have sufficient telomere length reserve to repopulate a myeloablatively treated host, despite continuous aging of HSCs in vivo and decreased repopulation ability of HSCs from older donors in vitro.

Factors predicting success or failure associated with common types of transplants

The ability to predict clinical outcomes is essential to accurate medical decision analysis. Many accepted bone marrow transplant related prognostic variables are derived from data that is over 20-years old and may or may not be applicable to current medical practice. This report reviews both older data concerning bone marrow transplantation prognostic factors as well as more current reports. In addition to pretransplant variables, this review examines easily measured post-transplant variables that may affect prognosis, as well as data concerning the cellular component of the infused graft in both allogeneic and autologous transplantation.

Clinical relevance of NK, NKT, and dendritic cell dose in patients receiving G-CSF-mobilized peripheral blood allogeneic stem cell transplantation

To analyze the relationship between the cellular composition of peripheral blood allografts and clinical outcome, we performed a prospective study in 45 adult patients who underwent allogeneic peripheral blood hematopoietic stem cell transplantation (HSCT) from a histocompatibility leukocyte antigen identical sibling donor for different hematological malignancies. The dose of CD34+, CD3+, CD4+, CD8+, and CD19+ lymphocytes, natural killer (NK) cells, natural killer T (NKT) cells, type 1 and type 2 dendritic cells (DC1 and DC2), as well as regulatory T (Treg) lymphocytes was analyzed. All patients were conditioned with busulphan and cyclophosphamide (BuCy2) +/- VP-16 and received a short course of methotrexate and cyclosporin-A as graft-versus-host disease (GVHD) prophylaxis. Acute GVHD (aGVHD) was present in 9 of 43 (21%) patients, and chronic GVHD (cGVHD) developed in 18 of 39 (46%) patients. There was a significantly higher incidence of aGVHD in patients receiving more than 6x10(6)/kg CD34+ cells. In univariate analysis, variables associated with better survival were as follows: a dose of less than 1.5x10(7)/kg NKT cells and less than 1.7x10(6)/kg DC2 for disease-free survival (DFS), and a dose of less than 3x10(7)/kg NK cells, less than 1.5x10(7)/kg NKT cells, less than 3x10(6)/kg DC1, and less than 1.7x10(6)/kg DC2 for overall survival (OS). In the Cox regression analysis, the dose of NKT cells was the only variable associated with better DFS, while the doses of NK, NKT, and CD34+ cells (less than 8x10(6)/kg) were associated with better OS. In conclusion, different circulating cell populations, other than CD34+ cells, are also of relevance in predicting the clinical outcome after allogeneic peripheral blood HSCT.

Treatment of chronic hepatitis C virus in allogeneic bone marrow transplant recipients

We recently reported an increased incidence of cirrhosis in hepatitis C virus (HCV)-infected stem cell transplant (SCT) recipients. Here, we describe our experience in the treatment of these patients, which has been, to date, poorly reported in the literature. Among 99 HCV-infected HCT recipients, 36 had HCV-related liver lesions on biopsy requiring therapy. Owing to HCV treatment contraindications, only 61% of patients (22/36) could be treated. In all, 12 patients received more than one course of anti-HCV treatment if they had HCV RNA still detectable after the first course of treatment and no treatment contraindications. Combined therapy (pegylated interferon (IFN): n=9, or standard IFN: n=9, in combination with ribavirin) led to sustained virological response in 4/18 (20%) patients as compared to 2/20 (10%) in patients who received IFN alone. Hematological toxicity was more frequent with combined therapy. While anemia responded to erythropoietin and/or dose modification, thrombocytopenia usually led to treatment interruption (n=3). This study thus highlights the efficacy of combined therapy and emphasizes the fact that the undue safety concerns are not a problem when treating this particular population.

Cyclophosphamide and antithymocyte globulin as a conditioning regimen for allogeneic marrow transplantation in patients with aplastic anaemia: a long-term follow-up

A total of 81 severe aplastic anaemia patients, aged 2-63 years, received human leucocyte antigen-matched related marrow grafts after cyclophosphamide + antithymocyte globulin followed by postgrafting methotrexate + cyclosporin. Median follow-up was 9.2 years. Ninety-six per cent of patients had sustained engraftment, 24% developed acute graft-versus-host disease (GVHD), grade II in all but two patients, and 26% developed chronic GVHD; all surviving patients eventually responded to immunosuppressive therapy. Six patients developed cancer: one fatal lymphoma and five carcinomas (all five patients are now free of cancer). Survival was 88%. The regimen appeared well tolerated and effective in heavily pretreated patients with aplastic anaemia.

Hematologic aspects of myeloablative therapy and bone marrow transplantation

The transplantation of bone marrow cells or isolated hematopoietic stem cells from the bone marrow or peripheral blood is a widely utilized form of therapy for patients with incurable diseases of the hematopoietic and immune systems. Successful engraftment of the transplanted stem cells in an adequately prepared recipient normally leads to bone marrow reconstitution over a period of several weeks, accompanied by more gradual reconstitution of the immune system. Since the recipient is profoundly ill during the initial treatment period, laboratory data is critical for monitoring engraftment, detecting residual/recurrent disease, and identifying problems that may delay bone marrow reconstitution or lead to other medical complications. Accurate blood cell counts are imperative, and most bone marrow transplantation patients undergo periodic monitoring with bone marrow aspirates and biopsies with cytogenetic, molecular, and multiparametric flow cytometric studies. The potential complications of bone marrow transplantation include engraftment failure and delayed engraftment, infection, residual bone marrow disease, acute and chronic graft versus host disease, myelofibrosis, therapy-related acute leukemia, post-transplant lympho-proliferative disorders, and toxic myelopathy.

Influence of T-cell depletion on chronic graft-versus-host disease: results of a multicenter randomized trial in unrelated marrow donor transplantation

Donor-derived T cells have been proposed to play a role in pathogenesis of chronic graft-versus-host disease (cGVHD). The impact of ex vivo T-cell depletion (TCD) on cGVHD was analyzed in a randomized multicenter trial involving unrelated donor marrow transplants. A total of 404 patients diagnosed with hematologic malignancies received a total body irradiation-based myeloablative conditioning regimen. GVHD prophylaxis included TCD plus cyclosporine (CSA) or unmodified grafts with CSA plus methotrexate (M/C). Median recipient age was 31.2 years (range, 0.5-55.6 years); median follow-up time since randomization was 4.2 years. The mean number of T cells infused was 1 log lower on the TCD arm. The incidence of cGVHD at 2 years was similar between the TCD and M/C arms, 29% versus 34% (P = .27), respectively. Survival at 3 years from diagnosis of cGVHD was also similar, (TCD 51% versus M/C 58%; P = .29). The proportion of patients with cGVHD who discontinued immunosuppression at 5 years was not different (TCD 72% versus M/C 63%; P = .27), and incidence of serious infections and leukemia relapse were similar on both treatment arms. In spite of a significant reduction of acute GVHD, TCD did not reduce the incidence of cGVHD or improve survival in patients who developed cGVHD.

A 10-year median follow-up study after allogeneic stem cell transplantation for chronic myeloid leukemia in chronic phase from HLA-identical sibling donors

We report long-term outcome in 102 patients with cCML transplanted from an HLA-identical sibling donor from 1982 to 1998. The conditioning regimen was based on cyclophosphamide associated with either total body irradiation (TBI) (37 patients) or with busulfan (63 patients). Graft-versus-host disease (GvHD) prophylaxis consisted of cyclosporin and methotrexate in the majority of the patients. Fifteen year overall survival was estimated at 53% (95% confidence interval (CI), 44-65) with a plateau after 2.5 years. Long-term survival was adversely affected by: longer time from chronic myeloid leukemia (CML) diagnosis to transplantation, older age at time of transplantation and GvHD (acute grade III-IV or chronic extensive). The main cause of death was infection, related to GvHD in 69% of patients. Splenectomy also significantly increased the risk of bacterial infection. 15-year relapse was estimated at 8% (95% CI, 0.1-14). Late malignancies occurred in seven patients, four of whom had an invasive cancer. Other frequent late complications included cataracts, psychological depression, osteonecrosis and hypothyroidism. These complications were more frequent following splenectomy, TBI and in patients with chronic extensive GvHD. We conclude that allogeneic transplantation with a related donor can cure more than half of CML patients in chronic phase, although physicians should be alert to long-term complications.

Granulocyte colony-stimulating factor for poor graft function after allogeneic stem cell transplantation: 3 days of G-CSF identifies long-term responders

Poor graft function (PGF) is a frequent cause of morbidity after allogeneic hematopoietic stem cell transplantation (allo-HSCT). To study the value of granulocyte colony-stimulating factor (G-CSF) in PGF, we retrospectively analyzed 81 episodes of PGF in 66 patients transplanted from 01/94 to 01/99 from an HLA-identical sibling (n = 45) or an unrelated (n = 21) donor. Median age was 29 years, 55 patients had malignancies. A total of 11 patients received a CD34+ selected graft. Viral infections (25%), myelotoxic drug (33%), fungal/bacterial infections (14%), and GVHD (31%) were present before PGF diagnosis. Median time from allo-HSCT to PGF was 75 (25-474) days. All patients were treated with G-CSF. In 77/81 episodes, there was a response that was sustained in 57. A total of 27 patients presented an increase of white cell count (WBC) >0.1 x 10(9)/l after 3 days of G-CSF. The 5-year survival was 37% and was significantly better in patients with increased WBC > 0.1 x 10(9)/l after 3 days of G-CSF (65 vs 18%, P < 0.0001). In multivariate analysis, increased WBC > 0.1 x 10(9)/l after 3 days of G-CSF (P = 0.002) was associated with better survival, while BuCy-based conditioning (P = 0.02) and GVHD (P = 0.005) were associated with higher risk of death. In conclusion, hematological response after 3 days with G-CSF predicted a better survival for patients with PGF after allo-SCT.

Infused CD34+ cell dose predicts long-term survival in acute myelogenous leukemia patients who received allogeneic bone marrow transplantation from matched sibling donors in first complete remission

Allogeneic stem cell transplantation (ASCT) has improved the outcome of acute myelogenous leukemia (AML). To further improve the treatment outcome of ASCT in AML, finding a modifiable prognostic factor is mandatory. We evaluated the effect of CD34(+) cell dose on survival in allogeneic bone marrow transplantation (BMT) from HLA-matched sibling donors for AML patients in first complete remission (CR1). The 99 patients included in our analysis were classified into high CD34(+) cell dose group (CD34(+) cells > or = 2.5 x 10(6)/kg) and low CD34(+) cell dose group (CD34(+) cells < 2.5 x 10(6)/kg). The high CD34(+) cell dose patients had better overall survival (5-year overall survival rate, 75% +/- 6% vs 52% +/- 9%; P = .01) and leukemia-free survival (5-year leukemia-free survival rate, 70% +/- 6% vs 44% +/- 9%; P = .04). CD34(+) cell dose was the only independent prognostic factor in overall survival and leukemia-free survival. The high CD34(+) cell dose group had a lower relapse incidence with a borderline statistical significance (5-year relapse rate, 27% +/- 6% vs 50% +/- 10%; P = .09). There were no differences in the engraftment of neutrophil and platelet, grade II-IV acute graft-versus-host disease (GVHD), extensive-stage chronic GVHD, and transplant-related mortality between the high and low CD34(+) cell dose groups. We confirmed that high CD34(+) cell dose favorably affects the outcomes in allogeneic BMT for AML. The effort to attain a high CD34(+) cell dose should be pursued during bone marrow harvest in allogeneic BMT for AML in CR1.

The effect of peptide stimulation on haematopoietic stem cell mobilisation including engraftment characteristics and a note on donor side effects

Aplasia or irreversible bone marrow failure and a variety of haematologic malignancies, as well as an increasing number of solid tumours, currently include various forms of marrow or equivalent transplantation in routine management. In both allogeneic and autologous procedures stable recipient immunohaematopoietic reconstitution depends upon infusing the requisite population harvested at a precise time following commencement of a stimulatory peptide. In a first step this prospective study documented the safety of apheresis, defined side effects and enumerated mononuclear, CD34+ and CD3+ cells obtained. In the second stage delivery of the graft, characterised in this way and with the additional measurement of in vitro growth in clonogenic assay, to the suitably conditioned patient was correlated with recovery of neutrophil and platelet numbers appearing in the circulation. In a third and ongoing analysis the influence of passenger T-lymphocytes is being evaluated for impact on infection and a potential anti-tumour effect. The conclusion is that this technology is reliable, has a high degree of patient acceptability without untoward complications, and that local results correspond to international experience thereby providing an important and relevant measure of quality control.

Long-term antifungal prophylaxis in high-risk hematopoietic stem cell transplant recipients

The risks for invasive fungal infections, particularly mould infections such as invasive aspergillosis, among hematopoietic stem cell transplant (HSCT) recipients are linked to the duration and severity of myelosuppression and immunosuppression. Strategies to prevent invasive fungal infections have focused primarily on the use of orally administered azole antifungal agents during the neutropenic period rather than on the more prolonged post-engraftment period. The major limitations of these studies included the heterogeneity among the subjects studied for fungal infection risk factors, the agents administered, the dosing, and duration of prophylaxis. More recent studies have attempted to examine the efficacy of antifungal prophylaxis strategies among allogeneic HSCT recipients to day 100 and beyond. It is clear that a variety of products have efficacy in preventing invasive candidiasis, including imidazole and triazole antifungals, low-dose amphotericin B, and the echinocandin, micafungin; however, only the extended spectrum azole, itraconazole, has been shown to impact the incidence of proven invasive aspergillosis. Other extended spectrum azole antifungal agents, voriconazole and posaconazole, are being studied as long-term prophylaxis in high-risk HSCT recipients. While clinical trials have suggested that a duration of prophylaxis against moulds of six months or more may be required, it remains unclear if this is required in all cases. The prophylactic efficacy over time may be linked to the degree of immunosuppression as measured by markers such as the numbers of circulating CD4 T lymphocytes. Concerns about selection for resistant moulds among long-term recipients of these drugs are emerging. The cumulative experience to date suggests that long-term antifungal chemoprophylaxis is feasible and effective when applied in defined circumstances. The concerns about treatment-related toxicities, resistance, and costs are valid.

Cord blood transplant: strategy of alternative donor search

Unrelated cord blood transplantation has been used to treat patients with malignant and non-malignant hematopoietic disorders for whom an HLA-compatible hematopoietic stem cell donor is not available. The establishment of cord blood banks worldwide, the increased number of cord blood units frozen, and the shorter time to find a donor, have made it possible to use this source of hematopoietic stem cells to treat more than 2,500 patients. The Eurocord registry was established to study the clinical results of cord blood transplantation and to compare the outcomes of unrelated transplants using either cord blood or bone marrow. Briefly, we have found, in two distinct retrospective analyses of children or adults with acute leukemia given either an unrelated cord blood or bone marrow transplant, that leukemia-free survival and relapse were similar in both types of graft (with adjustment for confounding clinical factors). Cord blood recipients experienced a decreased incidence of acute graft-versus-host disease and delayed hematopoietic recovery compared to bone marrow recipients. To improve the delayed hematopoietic recovery after cord blood transplantation, certain approaches have been investigated such as ex vivo expansion of cord blood cells, double cord blood transplantation and reduced intensity conditioning regimen. We have also attempted to establish some guidelines for cord blood-donor choice based on cord blood cell dose and number of HLA disparities that have been found to be associated with hematopoietic recovery. In conclusion, an unrelated hematopoietic stem cell donor should be simultaneously searched for in cord blood banks and in bone marrow donor registries for patients lacking an HLA-identical sibling hematopoietic stem cell donor. The option of performing cord blood transplants should be based on urgency of the transplant, cord blood cell dose and number of HLA disparities.

Unrelated peripheral blood and cord blood hematopoietic stem cell transplants for thalassemia major

Allogeneic hematopoietic stem cell transplantation is currently the only curative treatment available for thalassemia major. While sibling donors are usually used, unrelated bone marrow transplants have also recently been found to be successful. In this report of two patients, we show that, besides using unrelated bone marrow, peripheral blood stem cell and cord blood transplantations from unrelated donors are viable options. We believe a significant contributory factor in both our cases was the large cell dose used.

Long-term outcome after bone marrow transplantation for severe aplastic anemia

From January 1978 to December 2001, 133 patients with severe aplastic anemia (SAA) underwent non-T cell-depleted allogeneic bone marrow transplantation from an HLA-identical sibling donor, at the Hospital Saint Louis using either the combination of cyclophosphamide (Cy) and thoracoabdominal irradiation (TAI; n = 100) or Cy and antithymocyte globulin (ATG; n = 33), as a conditioning regimen. With 13.6 years of follow-up, the 10-year survival estimate was 64%. Four factors were associated with lower survival: older age, use of Cy-TAI, any form of treatment prior to transplantation (either androgens or immunosuppressive therapy, [IST]), and grade II to IV acute graft-versus-host disease (GvHD). TAI was the sole factor associated with the occurrence of acute GvHD. The risk of cancers (15-year cumulative incidence, 10.9%) was associated with older age and with the use of cyclosporine as IST before transplantation. Cumulative incidences and risk factors of nonmalignant late effect including avascular osteonecrosis and late bacterial, viral, and fungal infection were also analyzed. Improved results using Cy-ATG as conditioning can lead to more than 90% chance of cure in patients with SAA. Even if, in our experience, the role of Cy-ATG versus that of Cy-TAI remained inextricably related to the year of transplantation, the major detrimental role of the GvHD disease in the long-term outcome and its relation to TAI supports avoidance of irradiation in the conditioning regimen. Furthermore, avoidance of any IST before transplantation in patients with a sibling donor is a prerequisite for attaining such excellent results.

Prognostic value of apoptotic cells and infiltrating neutrophils in graft-versus-host disease of the gastrointestinal tract in humans: TNF and Fas expression

The gastrointestinal (GI) tract is a major target in graft-versus-host disease (GvHD). In rodents both tumor necrosis factor (TNF) and Fas-dependent apoptosis have been shown to play a major role in GvHD lesions, but data in humans on TNF and Fas in situ expression are scarce. More recently, the role of non-T cells as GvHD effectors has also been suggested in experimental models. Here we report a detailed quantitative pathologic analysis in 95 patients who underwent gastroduodenal biopsy. This analysis included characterization and quantification of the cellular infiltrate, TNF, TNF receptors, and Fas in situ expression analyses and quantification of apoptotic cell numbers. TNF was expressed in all biopsies and it was highly specific for acute GvHD. In multivariate analysis, including pathologic factors only, increased early transplant-related mortality (TRM) was associated with the presence of more than 20 neutrophils per field. Factors affecting early and late TRM were then assessed by multivariate analyses including both pathologic and clinical factors. Increased day-90 TRM was associated with the presence of more than 5 apoptotic bodies per field within the cellular infiltrate, and with stage II or higher acute liver GvHD. One-year TRM associated with the same 2 factors and with chronic GvHD.

T-cell alloreactivity dominates natural killer cell alloreactivity in minimally T-cell-depleted HLA-non-identical paediatric bone marrow transplantation

Natural killer (NK) cell alloreactivity resulting from killer immunoglobulin-like receptor (KIR) ligand incompatibility improves outcomes in patients receiving extensively T-cell-depleted bone marrow (BM) grafts. Patients with KIR ligand incompatibility are at risk for donor T-cell alloreactivity. We investigated the relative significance of NK-cell and T-cell alloreactivity in 105 paediatric patients who received a minimally T-cell-depleted human leucocyte antigen-non-identical BM transplantation. Donor NK-cell incompatibility did not improve patient outcome [engraftment, graft-versus-host disease (GVHD), relapse or overall survival]. In contrast, donor T-cell incompatibility was a risk factor for acute GVHD, chronic GVHD and death. Thus, T-cell alloreactivity dominated that of NK cells in minimally T-cell-depleted grafts.

Long-term outcome of hepatitis C infection after bone marrow transplantation

Chronic hepatitis C is often asymptomatic, at least during the first decade following hematopoietic stem cell transplantation. Progression to advanced liver disease or cirrhosis in patients surviving more than 10 years is currently thought to be rare. Among 1078 patients who underwent an allogeneic transplantation between January 1973 and January 1995, 96 patients infected by hepatitis C virus (HCV) during the transplantation period were studied. Cumulative incidence and analysis of risk factors for cirrhosis were analyzed, and the rate and risk of cirrhosis in transplant recipients were compared with those of 158 HCV-infected controls who did not receive transplants. At a median follow-up of 15.7 years, 15 patients developed biopsy-proven cirrhosis, leading to a cumulative incidence of cirrhosis of 11% and 24% at 15 and 20 years, respectively. By multivariate analysis, extrahepatic HCV manifestations and HCV genotype 3 were associated with risk of cirrhosis. The median time to cirrhosis in transplant recipients was 18 years as compared with 40 years in the control population. The risk of cirrhosis in transplant recipients relative to controls was significantly higher by multivariate analysis (P =.0008). Roughly a quarter of long-term HCV-infected survivors with transplants progressed to cirrhosis that is much more rapid than in patients without transplants. Systematic detection of HCV infection, liver biopsy, and therapeutic intervention are therefore warranted in long-term marrow transplant recipients.

Allogeneic graft CD34+ cell dose correlates with dendritic cell dose and clinical outcome, but not with dendritic cell reconstitution after transplant

OBJECTIVE

This study examined whether the CD34(+) cell dose in allografts correlates with the dose of myeloid dendritic cells (mDC) and plasmacytoid DC (pDC), and with DC reconstitution and clinical outcome after a myeloablative HLA-matched transplant.

PATIENTS AND METHODS

Fifty-three patients were included in this study: 37 who had undergone a granulocyte colony-stimulating factor mobilized peripheral blood stem cells (PBSC) transplant from related donors and 16 who had undergone a marrow transplant from unrelated donors. The number of CD34(+) cells, lin(-)HLA-DR(+)CD11c(+) mDC, lin(-)HLA-DR(+)CD123(+) pDC, CD14(+) monocytes, and CD3(+)CD4(+), CD3(+)CD8(+), CD56(+), and CD19(+) lymphocytes was compared in the graft, as well as in the peripheral blood after transplant, in patients receiving more than versus less than or equal to the median number of CD34(+) cells in PBSC (5.78 x 10(6)/kg) or in marrow (2.8 x 10(6)/kg).

RESULTS

A higher CD34(+) cell dose was associated with larger numbers of mDC in PBSC (p=0.01) and pDC in marrow grafts (p=0.004). However, neither mDC nor pDC recovery after transplant correlated with the number of CD34(+) cells infused. Finally, higher doses of CD34(+) cells appeared to negatively affect (p=0.02) the overall survival in PBSC transplantation and were associated with a trend for higher acute graft-vs-host disease in PBSC and lower acute graft-vs-host disease in marrow transplant.

CONCLUSIONS

CD34(+) cell dose correlates with the dose of different DC subsets in PBSC and marrow grafts, but it does not affect DC reconstitution after transplant. Higher doses of CD34(+) cells in PBSC, but not in marrow, seem to adversely affect survival after transplant.

Impact of CD34+ cell dose on the outcome of patients undergoing reduced-intensity-conditioning allogeneic peripheral blood stem cell transplantation

We analyzed the impact of CD34+ cell dose on the outcome of 86 patients undergoing reduced-intensity conditioning (RIC) allogeneic peripheral blood stem cell transplantation. The RIC was based on fludarabine 150 mg/m2 and melphalan 140 mg/m2 or busulphan 10 mg/kg. A median of 5.68 x 106 CD34+ cells/kg and 2.86 x 108 CD3+ cells/kg were infused. All patients receiving more than percentile 75 (p75) of CD34+ cells reached complete chimerism in T lymphocytes by days 21 to 28, compared with 44% among those receiving p75 or fewer cells (P =.046). Overall, 30.3% patients developed grade 2 to 4 acute graft-versus-host disease (aGVHD). Among 83 evaluable patients, 55.8% developed chronic GVHD (cGVHD). The dose of CD34+ cells infused did influence the development of cGVHD, with a cumulative incidence of extensive cGVHD of 74% vs 47% (P =.02) among patients receiving more than p75 CD34+ cells vs those receiving p75 or fewer. Projected overall survival (OS) and event-free survival (EFS) at 43 months were 60% and 46%, respectively. Neither the dose of CD34+ cells nor the dose of CD3+ cells infused significantly influenced OS and EFS, although among patients categorized as high-risk, 36% of those receiving p75 or fewer CD34+ cells relapsed or progressed, compared with only 9% among those receiving more than p75 CD34+ cells (P =.07). Among patients receiving p75 or fewer CD34+ cells, 36% of high-risk patients relapsed, compared with 10% of low- and intermediate-risk patients (P =.004), while relapse rates were not significantly different between both subgroups when we infused more than p75 CD34+ cells, thus indicating that infusing high doses of CD34+ cells ameliorates the negative effect of advanced disease status at transplantation. cGVHD was associated with better EFS (63% vs 16% at 43 months for patients with and without cGVHD; P <.0001) and better OS (78% vs 28% for patients with and without cGHVD; P <.001). The number of CD34+ cells infused should be tailored to prevent extensive cGVHD among patients categorized as low-risk, while high-risk patients, in whom the graft-versus-leukemia effect may determine disease outcome, should receive high doses of CD34+ cells.

Impact of transplanted CD34+ cell dose in allogeneic unmanipulated peripheral blood stem cell transplantation

The impact of the CD34+ cell dose on chronic graft-versus-host disease (cGVHD) and the clinical outcome was analyzed in 41 consecutive adult patients submitted to allogeneic peripheral blood stem cell transplantation from HLA-identical siblings. The patients were classified into 'low' or 'high' CD34+ cell dose groups based on whether they received less or more than a median CD34+ cell dose of 10.5 x 10(6)/kg, respectively. There was a significant difference in the incidence of extensive cGVHD (low vs high group, 25.0 vs 66.7%, P=0.021) and relapse (47.6 vs 20.0%, P=0.049) between the two groups. With a median follow-up of 335 days, the 3-year survival estimate for the whole population was 47.9%, while that for the low and high groups was 29.9 and 67.8%, respectively (P=0.0434). An inverse relation was noted between the relapse rate and the incidence of extensive cGVHD (P=0.043). It would appear reasonable that the optimal dose of CD34+ cells should be determined based on the disease status or aggressiveness of the malignant cells in each patient. Yet, in the case of patients with a high risk of relapse, transplantation with a CD34+ cell dose of >10.5 x 10(6)/kg would seem to be acceptable to minimize the risk of relapse.

HLA-identical stem cell transplantation: is there an optimal CD34 cell dose?

A review of the published literature, supplemented with a recent analysis of Fred Hutchinson data, has been undertaken to investigate the association of infused CD34 cell dose with various clinical outcomes after HLA-identical transplantation. Separate assessments for unrelated vs related donors and the use of bone marrow or mobilized G-PBMC have been incorporated. The three primary findings are: (1) higher CD34 dose results in better neutrophil and platelet recovery in all settings; (2) high CD34 doses (>8 x 10(6)/kg) are associated with the development of more chronic GVHD when using related G-PBMC; (3) higher CD34 dose is correlated with improved survival after bone marrow transplantation, especially with unrelated donors. This is not seen when using G-PBMC. The data suggest that the CD34 content of the graft can have a significant impact on clinical outcome after allogeneic transplantation, but optimal dose is dependent on both donor type and stem cell source.

T-cell depletion with Campath-1H "in the bag" for matched related allogeneic peripheral blood stem cell transplantation is associated with reduced graft-versus-host disease, rapid immune constitution and improved survival

We studied the outcome of 24 peripheral blood stem cell (PBSC) graft recipients, who were T-cell depleted (TCD) with either 20 mg (n = 14) or 10 mg (n = 10) Campath-1H in vitro, in comparison with a retrospective cohort of 23 unmanipulated (UM) PBSC recipients. While the neutrophil engraftment was similar, the platelet engraftment occurred earlier in the TCD group (d 11 vs 14). The incidence of acute and chronic graft-versus-host-disease (GVHD) was 8.7% and 4.4% in the TCD group, respectively, compared with 47.7% and 56.3% in UM group (P < 0.001). In the TCD group, 5/6 chronic myeloid leukaemia (CML) and 4/18 non-CML patients relapsed (vs 0/6 and 3/17 in UM group, P = 0.06). All four molecular or cytogenetic relapses of CML were disease-free survivors following donor lymphocyte infusion. There was no difference in the incidence of serious infection between the TCD and UM groups and the lymphocyte recovery at 100 d was comparable. In the TCD cohort, the lymphocyte recovery was quicker in the 10 mg Campath-1H group. The non-relapse mortality (19.1%vs 66.3%) and 3 year survival (73.1 vs 19.2) were improved in the TCD group (P = 0.05). Thus elimination of late mortalities related to chronic GVHD and a rapid immune reconstitution, limiting either infection or relapse related deaths, contributed to an improved outcome following T-cell depletion with Campath-1H "in the bag".

Clinical application of hematopoietic progenitor cell expansion: current status and future prospects

In the past decade, we have witnessed significant advances in ex vivo hematopoietic stem cell culture expansion, progressing to the point where clinical trials are being designed and conducted. Preclinical milestone investigations provided data to enable expansion of portions of hematopoietic grafts in a clinical setting, indicating safety and feasibility of this approach. Data derived from current clinical trials indicate successful reconstitution of hematopoiesis after myeloablative chemoradiotherapy using infusion of ex vivo-expanded perfusion cultures. Future avenues of exploration will focus upon refining preclinical and clinical studies in which cocktails of available cytokines, novel molecules and sophisticated expansion systems will explore expansion of blood, marrow and umbilical cord blood cells.