Selected Stro-1-enriched bone marrow stromal cells display a major suppressive effect on lymphocyte proliferation.

Mesenchymal stem cells (MSCs) have an immunosuppressive effect and can inhibit the proliferation of alloreactive T cells in vitro and in vivo. Cotransplantation of MSCs and hematopoietic stem cells (HSCs) from HLA-identical siblings has been shown to reduce the incidence of acute graft-vs.-host disease. MSCs are heterogeneous and data on the inhibitory effects of different MSC subsets are lacking. The antigen Stro1 is a marker for a pure primitive MSC subset. We investigated whether Stro-1-enriched induce a more significant suppressive effect on lymphocytes in a mixed lymphocyte reaction (MLR), and whether this action is related to a specific gene expression profile in Stro-1-enriched compared to other MSCs. We demonstrated that the Stro-1-enriched population elicits a significantly more profound dose-dependent inhibition of lymphocyte proliferation in a MLR than MSCs. One thousand expanded Stro-1-enriched induced an inhibitory effect comparable to that of 10 times as many MSCs. Inhibition by Stro-1-enriched was more significant in contact-dependent cultures than in noncontact-dependant cultures at higher ratio. The Stro-1-enriched inhibitory effect in both culture types was linked to increased gene expression for soluble inhibitory factors such as interleukin-8 (IL-8), leukemia inhibitory factor (LIF), indoleamine oxidase (IDO), human leukocyte antigen-G (HLA-G), and vascular cell adhesion molecule (VCAM1). However, tumor growth factor-beta1 (TGF-beta) and IL-10 were only up-regulated in contact-dependant cultures. These results may support using a purified Stro-1-enriched population to augment the suppressive effect in allogeneic transplantation.

Immunomodulatory effect of mesenchymal stromal cells: possible mechanisms.

Co-transplantation of mesenchymal stem cells (MSCs) and hematopoietic stem cells ameliorate hematopoietic reconstitution and induce tolerance. The immunomodulatory properties of MSCs have been demonstrated both in vivo and in vitro. MSCs can modulate function of immune cells such as T lymphocytes, antigen-presenting cells and natural killer cells. However, it is unknown whether MSCs given to patients that have undergone HSC transplantation could alleviate graft versus leukemia effect or could increase the risk of the infection. Proper characterization of MSC immunomodulatory mechanisms are crucial to anticipate the possible effect of MSC in the host. In the current report, interesting and contradictory results in the literature are reviewed in an attempt to understand the underlying mechanism. Differences in experimental designs and models used seem to be the underlying causes of discrepancy in reported results. Results of the few in vivo studies are controversial and further clinical studies are needed to confirm the efficiency and safety of MSCs in transplantation management.

Long-term follow-up of high-dose treatment with autologous haematopoietic progenitor cell support in 693 patients with follicular lymphoma: an EBMT registry study.

To evaluate the outcome of a large series of patients who received high-dose treatment (HDT) for follicular lymphoma (FL), 693 patients undergoing HDT (total-body irradiation (TBI)-containing regimen: 58%; autologous bone marrow (BM)/peripheral blood progenitor cells (PBPCs): 378/285 patients) were included in the study. A total of 375 patients (54%) developed recurrent lymphoma, 10-year progression-free survival (PFS) being 31%. On multivariate analysis, younger age (P=0.003) and HDT in first complete remission (CR1) (P<0.001) correlated with longer PFS. With a median follow-up of 10.3 years, 330 patients died. Ten-year overall survival (OS) from HDT was 52%. Shorter OS was associated on multivariate analysis with older age (P<0.001), chemoresistant disease (P<0.001), BM+PBPC as source of stem cells (P=0.007) and TBI-containing regimens (P=0.004). Thirty-nine patients developed secondary myelodysplastic syndrome/acute myeloid leukaemia (MDS/AML), in 34 cases having received TBI as the conditioning regimen. The 5-year non-relapse mortality (NRM) was 9%. On multivariate analysis, older age (P<0.001), refractory disease (P<0.001) and TBI (P=0.04) were associated with a higher NRM. This long follow-up study shows a plateau in the PFS curve, suggesting that a selected group of patients might be cured with HDT. On the downside, TBI-containing regimens are associated with a negative impact on survival.

Human bone marrow-derived mesenchymal stem cells.

Mesenchymal stem cells (MSCs) have elicited a great clinical interest, particularly in the areas of regenerative medicine and induction of tolerance in allogeneic transplantation. Previous reports demonstrated the feasibility of transplanting MSCs, which generates new prospects in cellular therapy. Recently, injection of MSCs induced remission of steroid-resistant acute graft-versus-host disease (GVHD). This review summarizes the knowledge and possible future clinical uses of MSCs.

Autologous stem cell transplantation for progressive multiple sclerosis: update of the European Group for Blood and Marrow Transplantation autoimmune diseases working party database.

Over the last decade, hematopoietic stem cells transplantation (HSCT) has been increasingly used in the treatment of severe progressive autoimmune diseases. We report a retrospective survey of 183 multiple sclerosis (MS) patients, recorded in the database of the European Blood and Marrow Transplantation Group (EBMT). Transplant data were available from 178 patients who received an autologous graft. Overall, transplant related mortality (TRM) was 5.3% and was restricted to the period 1995-2000, with no further TRM reported since then. Busulphan-based regimens were significantly associated with TRM. Clinical status at the time of transplant and transplant techniques showed some correlations with toxicity. No toxic deaths were reported among the 53 patients treated with the BEAM (carmustine, etoposide, cytosine-arabinoside, melphalan)/antithymocyte globulin (ATG) regimen without graft manipulation, irrespective of their clinical condition at the time of the transplant. Improvement or stabilization of neurological conditions occurred in 63% of patients at a median follow-up of 41.7 months, and was not associated with the intensity of the conditioning regimen. In this large series, HSCT was shown as a promising procedure to slow down progression in a subset of patients affected by severe, progressive MS; the safety and feasibility of the procedure can be significantly improved by appropriate patient selection and choice of transplant regimen.

A long-term follow-up of 33 patients with non-Hodgkin's lymphoma who received the BEAM high-dose intensification regimen with cytokine support only and no transplant.

High-dose intensification and autologous stem-cell transplantation (ASCT) is widely used to consolidate patients with non-Hodgkin's lymphoma (NHL), who have reached a stage of minimal residual disease. However, patients with persisting marrow and/or blood involvement and those who fail peripheral blood hemopoietic progenitor mobilization are excluded from ASCT. For such patients with no available graft to infuse, we developed 15 years ago, before the anti-CD20 monoclonal antibody therapeutic era, the use of the BEAM pretransplant regimen followed only by the administration of three cytokines (erythropoietin, granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor). We report here on the long-term follow-up of 33 patients treated with this approach. In all, 33 NHL patients underwent the BEAM (carmustine, VP-16, cytosine-arabinoside, melphalan) followed by the administration of the three cytokines from January 1994-2000. A backup marrow, albeit infiltrated by tumor cells, had been collected earlier and stored in all. A total of 30 patients (91%) recovered normal hematopoiesis. In total, 32 patients (97%) recovered neutrophils (>500/microl) at a median of 19 days and 30 patients (91%) recovered platelets (>20,000/microl) at a median of 26 days. Age, richness of backup graft and blood-hemoglobin level at intensification had an impact on the time for hematopoietic recovery (P=0.014, P=0.014, P=0.048). The median follow-up was 62 months. Five patients died from toxicity related to the procedure. Eight patients relapsed and died. A total of 20 patients (61%) are alive, 16 (49%) in complete remission. A 5-year disease-free survival was 52+/-9%, relapse incidence 35+/-16%, mortality due to the procedure 12+/-12% and overall survival 61+/-10%. The BEAM regimen is not myeloablative. The BEAM+3CK procedure is a feasible therapeutic option that has shown efficacy in poor risk NHL patients who were not eligible for autografting because of persisting marrow/blood tumor contamination, or poor hemopoietic progenitor harvesting. It is unclear today whether some of these patients would have cleared their marrow/peripheral blood with the additional use of anti-CD20 treatment, thereby making the classical approach (BEAM followed by the infusion of a clean autograft) feasible.

Patients with acute lymphoblastic leukaemia allografted with a matched unrelated donor may have a lower survival with a peripheral blood stem cell graft compared to bone marrow.

We analysed data for 213 patients with ALL and AML who received either peripheral blood stem cells (PBSC) (n=74) or bone marrow (BM) (n=139) from an HLA-matched unrelated donor (EBMT acute leukaemia registry; January 1994 to January 1999). The two groups of patients (by cell source) were comparable with respect to age, sex, disease status, year at transplant and graft T cell depletion. Engraftment was achieved in about 90% regardless of stem cell source or leukaemia type. Kinetics of neutrophil and platelet recovery, similar for both sources in ALL patients, were faster for PBSC in AML patients. The incidence of acute graft-versus-host disease was similar for both sources in AML patients, but higher for PBSC in ALL patients (74 vs 54%, P=0.05). The 1-year probability of chronic graft-versus-host disease was 40 and 45% (P=0.66) in ALL patients compared to 49 and 35% (P=0.13) in AML patients (PBSC vs BM). In AML patients, none of the following differed significantly with cell source: transplant-related mortality, relapse incidence, leukaemia-free survival and overall survival. In ALL patients, the transplant-related mortality for PBSC vs BM was 61 vs 47% (P=0.13), the relapse incidence was 47 vs 39% (P=0.17), the leukaemia-free survival was 21 vs 32% (P=0.04) and the overall survival was 24 vs 34% (P=0.04). These data suggest that the short-term outcome of allogeneic PBSC is not significantly different from that of BM in AML patients who underwent a transplant from a matched unrelated donor but, conversely, that survival with PBSC may be decreased in ALL patients. In conclusion, the source of transplant cells needs to be evaluated by disease, especially when dealing with unrelated donors.

Outcome of 5651 hematopoietic stem cell transplants for hematological malignancies carried out in Europe in 1993: a reliability study of the registry.

Outcome results of observational databases are frequently criticized as relying on incomplete information from incomplete patient populations. Few data are available to dispute these arguments of selection bias. The European Group for Blood and Marrow transplantation (EBMT) decided to address this question by evaluating the hematopoietic stem cell transplants performed in 1993. A comprehensive survey was launched in an effort to collect informations on all transplants for hematological malignancies performed throughout Europe during the year 1993. The main goals of this effort were to compare the group of spontaneously reported patients with the group of retrospectively solicited patients, and to give an accurate estimate of the outcome of all patients. For the year 1993, the annual EBMT activity survey indicated 6336 transplants performed for hematological malignancies in Europe. A total of 5651 transplants could be analyzed; 2595 were reported spontaneously by the teams (group A) and 3056 were retrieved on solicitation (group B). Patients and transplant characteristics for group A and B were very similar for most parameters with a few exceptions. There was no statistical difference for outcome at 3 years between groups A and B: disease-free survival (DFS) was 45 +/- 1% and 44 +/- 1%, relapse incidence (RI) 41 +/- 1% and 42 +/- 1%, transplant-related mortality (TRM) 23 +/- 1% and 23 +/- 1%, and overall survival (OS) 54 +/- 1% and 55 +/- 1%, respectively, for group A and group B. The real outcome at 3 years for the 5651 patients (group A + group B) transplanted in 1993 was 44 +/- 1%, 41 +/- 1%, 23 +/- 1%, and 54 +/- 1%, for DFS, RI, TRM and OS, respectively. The outcome at 3 years by transplant modality, autologous or allogeneic transplants, and by disease categories showed no difference between groups A and B.

Hematopoietic stem cell transplantation for multiple sclerosis. A retrospective multicenter study.

RATIONALE: Phase I/II studies of autologous hematopoietic stem cell transplantation (HSCT) for multiple sclerosis ( MS) were initiated, based on results of experimental transplantation in animal models of multiple sclerosis and clinical observations in patients treated concomitantly for malignant disease. PATIENTS: Eighty-five patients with progressive MS were treated with autologous HSCT in 20 centers and reported to the autoimmune disease working party of the European Group for Blood and Marrow Transplantation (EBMT). 52 (61 %) were female, median age was 39 [20-58] years. The median interval from diagnosis to transplant was 7 [1-26] years. Patients suffered from severe disease with a median EDSS score of 6.5 [4.5-8.5]. Active disease prior to transplant was documented in 79 of 82 evaluable cases. RESULTS: The stem cell source was bone marrow in 6 and peripheral blood in 79, and stem cells were mobilized into peripheral blood using either cyclophosphamide combined with growth factors or growth factors alone. Three patients experienced transient neurological complications during the mobilization phase. The high dose regimen included combination chemotherapy, with or without anti-lymphocyte antibodies or, with or without, total body irradiation. The stem cell transplants were purged of lymphocytes in 52 patients. Median follow-up was 16 [3-59] months. There were 7 deaths, 5 due to toxicity and infectious complications, 2 with neurological deterioration. The risk of death of any cause at 3 years was 10 (+/-7)% (95 % confidence interval). Neurological deterioration during transplant was observed in 22 patients; this was transient in most but was associated with MS progression in 6 patients. Neurological improvement by > or = 1 point in the EDSS score was seen in 18 (21 %) patients. Confirmed progression-free survival was 74 (+/-12)% at 3 years being 66 (+/-23)% in patients with primary progressive MS but higher in patients with secondary progressive or relapsing-remitting MS, 78 (+/-13)%; p = 0.59. The probability of confirmed disease progression was 20 (+/-11)%. MRI data were available in 78 patients before transplant showing disease activity (gadolinium enhancing, new or enlarging lesions) in 33 %. Posttransplant MRI showed activity at any time in 5/61 (8 %) evaluable cases. CONCLUSION: Autologous HSCT suggest positive early results in the management of progressive MS and is feasible. These multicentre data suggest an association with significant mortality risks especially in some patient groups and are being utilised in the planning of future trials to reduce transplant related mortality.

Improved efficiency of remission induction facilitates autologous BMT harvesting and improves overall survival in adults with AML: 108 patients treated at a single institution.

A hundred and eight patients less than 60 years old with de novo acute myeloid leukemia were treated between 1982 and 1994 by protocols including final intensification with a transplant using autologous bone marrow purged by mafosfamide in first remission in the absence of an HLA-matched sibling donor available for allograft. From 1989, we attempted to improve tumor control by using high-dose anthracyclines in induction, by increasing from one to two the number of consolidation courses pre-transplant and by introducing intermediate doses of cytarabine in the first consolidation course. The CR rate was 77% (33/43) before 1989 and 90% (59/65) after 1989 (P = 0.06). Forty-five out of the 59 patients (76%) who achieved CR after 1989 could undergo bone marrow grafting in CR1 vs 16/33 (48%) before 1989 (P = 0.01). In spite of the higher proportion of patients above 50 years after 1989 (32%) toxicity was mild and an adequate graft was obtained more frequently after one collection. The principal factor relating to improvement in graft feasibility was the post-1989 modification of induction and consolidation regimens. This improvement in graft feasibility was associated with a better disease-free survival (DFS) (48 +/- 7% vs 32 +/- 8%, P = 0.04) and overall survival (OS) (53 +/- 6% vs 30 +/- 7%, P = 0.007) at 5 years. By multivariate analysis four factors were associated with overall survival (OS): karyotype, white blood cell count at diagnosis, treatment regimen and bone marrow grafting in CR1. This global approach should be prospectively compared with intensive chemotherapy.

Ex vivo expansion of CD34-positive peripheral blood progenitor cells from patients with non-Hodgkin's lymphoma: no evidence of concomitant expansion of contaminating bcl2/JH-positive lymphoma cells.

The aim of the present study was to evaluate the capacity to expand of hematopoietic stem cell (HSC) samples from eight patients with NHL, and to follow in parallel the fate of tumor cells in four of eight samples still containing bcl2/JH+ tumor cells after CD34+ or CD19-/20-/34+ cell selection. The presence of bcl2/JH+ cells was also investigated after expansion in four of eight samples, two of which were bcl2/JH at harvesting and two which were initially bcl2/JH+ but became bcl2/JH (below the level of PCR detection) after cell selection, to assess a possible reappearance of occult tumor cells after expansion culture. We used culture conditions that we previously had established to allow high level expansion of normal precursors, progenitors and LTC-ICs. In this study, particular attention was given to the role of Flt3-ligand, known to favor the growth of B cells. The expansion conditions were: 1.5 x 10(3) cells/ml in serum-free medium containing stem cell factor (SCF), interleukin-3 (IL-3), IL-6, granulocyte-stimulating factor (G-CSF), erythropoietin (Epo) +/- Flt3-ligand (Flt3-L) for 10 days. After culture, total cells, CFU-GMs, BFU-Es and LTC-ICs were expanded to a mean of 833-, 6.6-, 4.6-, and 1.8-fold, respectively with the cocktail of cytokines not including Flt3-L. When Flt3-L was added, the mean expansion values were 1095-, 31-, 15- and three-fold, respectively. Residual bcl2/JH+ cells present in four of eight samples before expansion were not detected after expansion. Similarly, no tumor cells reappeared after expansion of the two samples which had become negative after selection, as well as in the two samples which were bcl2/JH- at harvesting. These results suggest first that ex vivo expansion of hematopoietic stem cells in patients with non-Hodgkin's lymphoma is feasible without incurring the parallel risk of amplifying tumor cells; second, that Flt3-L did not stimulate the growth of tumor cells while it clearly favored the growth of normal progenitors.

Feasibility and recent improvement of autologous stem cell transplantation for acute myelocytic leukaemia in patients over 60 years of age: importance of the source of stem cells.

A total of 193 patients with acute myelocytic leukaemia (AML) [147 in first complete remission (CR1)], ranging from 60 years to 75 years of age (median 63 years), were autografted between January 1984 and December 1998. The source of stem cells was peripheral blood (PB) in 128 patients, bone marrow in 51 patients and a combination of both in 14 patients. Total body irradiation (TBI) was used in 34 cases. Ninety-seven per cent of patients had successful engraftment of neutrophils on day 15 (range days 7-71) and of platelets on day 30 (range days 9-894). In patients autografted in CR1, the transplant-related mortality (TRM) was 15 +/- 4%, the relapse incidence (RI) was 58 +/- 5%, the leukaemia-free survival (LFS) was 36 +/- 5% and the overall survival was 47 +/- 5% at 3 years. The source and dose of stem cells were studied in particular; in patients transplanted in CR1, the RI was 44 +/- 11% in those receiving marrow compared with 63 +/- 6% in those receiving PB (P = 0.04). Patients autografted in CR1 who received higher granulocyte-macrophage colony-forming units (CFU-GM) doses (above the median) had a lower RI (47 +/- 11% vs. 79 +/- 9%, P = 0.009). There was a significant improvement in patients transplanted after March 1996; for those in CR1, the RI was 41 +/- 8% vs. 65 +/- 6% (P = 0.01), the LFS was 53 +/- 8% vs. 28 +/- 5% (P = 0.01) and the overall survival was 72 +/- 7% vs. 36 +/- 6% (P = 0.02). By multivariate analyses, significant factors for the outcome were the date of transplant with recent improvement and the source of stem cells, with a lower RI for marrow. Autologous stem cell transplantation (ASCT) is a potential therapeutic approach in patients with AML over 60 years of age; results have improved recently.

The dismal outcome in patients with acute leukaemia who relapse after an autograft is improved if a second autograft or a matched allograft is performed. Acute Leukaemia Working Party of the European Group for Blood and Marrow Transplantation (EBMT).

All patients receiving autografts for acute leukaemia in remission between 1 January 1981 and 31 December 1996 and reported to the European Group for Blood and Marrow Transplantation and had a relapse, were included. The patients underwent an allograft (n = 90, group A), were treated with chemotherapy (n = 2584, group B) or received a second autograft (n = 74, group C). The 2-year survival after relapse was 32 +/- 5%, 11 +/- 1% and 42 +/- 6% in groups A, B and C, respectively. In group A, those with an HLA-A, -B and -DR compatible related or unrelated donor had a 2-year survival of 37 +/- 7% compared to 13 +/- 8% for those receiving a graft from an HLA mismatched donor (n = 20). The following factors were associated with better survival in multivariate analyses: an interval from first autograft to relapse >5 months (P < 0.00001), a first autograft performed later than 1991 (P < 0.00001), patient age below 26 years (median, P < 0.002), group B vs HLA mismatches from group A (P = 0.002), group C vs group B (P < 0.005), patients who were not treated with total body irradiation at first autograft (P < 0.02) and patients in first remission at first autograft (P = 0.02). To conclude, the poor outcome in these patients was improved if a second autograft was feasible (P < 0.005), or if an HLA-matched allograft was performed (NS). Bone Marrow Transplantation (2000).