Bone marrow transplantation using unrelated donors for haematological malignancies

Alpha/beta T-cell depleted grafts as an immunological booster to treat graft failure after hematopoietic stem cell transplantation with HLA-matched related and unrelated donors

Allogeneic hematopoietic stem cell transplantation is associated with several complications and risk factors, for example, graft versus host disease (GVHD), viral infections, relapse, and graft rejection. While high levels of CD3+ cells in grafts can contribute to GVHD, they also promote the graft versus leukemia (GVL) effect. Infusions of extra lymphocytes from the original stem cell donor can be used as a treatment after transplantation for relapse or poor immune reconstitution but also they increase the risk for GVHD. In peripheral blood, 95% of T-cells express the αβ T-cell receptor and the remaining T-cells express the γδ T-cell receptor. As αβ T-cells are the primary mediators of GVHD, depleting them from the graft should reduce this risk. In this pilot study, five patients transplanted with HLA-matched related and unrelated donors were treated with αβ T-cell depleted stem cell boosts. The majority of γδ T-cells in the grafts expressed Vδ2 and/or Vγ9. Most patients receiving αβ-depleted stem cell boosts increased their levels of white blood cells, platelets, and/or granulocytes 30 days after infusion. No signs of GVHD or other side effects were detected. A larger pool of patients with longer follow-up time is needed to confirm the data in this study.

Immune Reactions following Cord Blood Transplantations in Adults

Cord blood transplantation (CBT) is an attractive alternative therapy in adult patients with advanced hematological malignancies in whom matched donors are unavailable. However, the risk of complications, especially infections, post-CBT increases the mortality rates in these patients. Although the incidence of acute and chronic graft versus host disease (GVHD) post-CBT is lower than that following bone marrow transplantation and peripheral blood stem cell transplantation (SCT), the additional immunosuppressive therapy required to treat it could increase the mortality in these patients. Further, chronic GVHD following CBT is milder and responds better to treatment than that occurring after bone marrow transplants. Unlike bone marrow transplantation, the onset of GVHD is a positive prognostic indicator of overall survival in patients receiving CBT, due to the graft versus malignancy (GVM) effect. This paper focuses on the immune reactions following CBT and aims to elucidate a management strategy for acute and chronic GVHD.

Reduced intensity conditioning compared with myeloablative conditioning using unrelated donor transplants in patients with acute myeloid leukemia

PURPOSE

Reduced intensity conditioning regimen (RIC) is increasingly used in hematopoietic stem cell transplantation (HSCT). Unrelated donor (UD) transplants have more complications. We wanted to examine if RIC is a valid treatment option using UD in acute myeloblastic leukemia (AML).

PATIENTS AND METHODS

Between 1999 and 2005, 401 patients with AML were treated with RIC and 1,154 received myeloablative conditioning (MAC), using UD and reported to the European Group for Blood and Marrow Transplantation Registry. Patients < and > or = 50 years of age were analyzed separately.

RESULTS

Patients receiving RIC were older, received transplants more recently, received peripheral blood stem cells more frequently, and were treated with total-body irradiation less often. In multivariable analysis, in patients younger than 50 years of age, nonrelapse mortality (NRM) was similar using RIC (hazard ratio [HR], 0.85; P = .41), relapse was increased (HR, 1.46; P = .02) and leukemia-free survival (LFS) was the same (HR, 0.88; P = .28), as compared with MAC. In patients > or = 50 years of age, NRM was decreased in the RIC group (HR, 0.64; P = .04), relapse probability was not significantly different (HR, 1.34; P = .16) and LFS was similar (HR, 1.04; P = .79) compared with MAC. CONCLUSION RIC-UD transplants are associated with higher relapse in AML patients younger than 50 years of age and decreased NRM in those > or = 50 years compared with MAC-UD. LFS was similar after both conditioning regimens, regardless of age. Therefore, RIC-UD extend the use of allotransplants for elderly patients and strategies that decrease relapse should be considered mainly in younger patients with AML.

Chronic graft-versus-host disease following umbilical cord blood transplantation: retrospective survey involving 1072 patients in Japan

We have little information on chronic graft-versus-host disease (GVHD) after cord blood transplantation (CBT). We investigated its clinical features in 1072 Japanese patients with hematologic malignancies who received a transplant through the Japan Cord Blood Bank Network. The primary end point was to investigate the incidence of any chronic GVHD. Median age of the patients was 33 years (range, 0-79 years). The cumulative incidence of chronic GVHD 2 years after transplantation was 28%. Chronic GVHD was fatal in 29 patients. Multivariate analysis demonstrated that development of chronic GVHD was favorably associated with both overall survival and event-free survival. Multivariate analysis identified risk factors of chronic GVHD: higher patient body weight, higher number of mismatched antigens for GVHD direction, myeloablative preparative regimen, use of mycophenolate mofetil in GVHD prophylaxis, and development of grades II to IV acute GVHD. Although chronic GVHD is a significant problem after CBT, it is associated with improved survival, perhaps due to graft-versus-malignancy effects.

Clinical characteristics of chronic graft-versus-host disease following umbilical cord blood transplantation for adults

Chronic GVHD is a significant complication following allogeneic hematopoietic stem cell transplantation; however, the clinical characteristics of chronic GVHD following cord blood transplantation (CBT) in adults have not been well described. Between March 2001 and November 2005, a total of 77 patients underwent CBT at eight transplantation centers of the Nagoya Blood and Marrow Transplantation Group. Of 77 patients, 29 survived without graft failure or progression of underlying diseases for at least 100 days after transplantation. The median age of the 29 patients was 42 years (range, 18-67 years). Seven patients developed chronic GVHD (extensive, n=4; limited, n=3) disease. The cumulative incidence of chronic GVHD 1 year after day 100 was 24% (95% confidence interval (CI), 11-41%), and the organs involved were the skin (n=6), oral cavity (n=4), liver (n=1) and gastrointestinal tract (n=1). In three patients, chronic GVHD was resolved with supportive care. The remaining four were successfully treated with additional immunosuppressive therapy. Event-free survival rates of the 29 patients with and without chronic GVHD 3 years after day 100 were 83 (95% CI, 27-97%) and 36% (95% CI, 17-56%), respectively (P=0.047). These results suggest that chronic GVHD following CBT is mild and has a graft-versus-malignancy effect.

Allogeneic hematopoietic stem cell transplantation: state of the art and new perspectives

Allogeneic hematopoietic stem cell transplantation (ASCT) is a well-established therapy for leukemias and other immunohematopoietic disorders. In more recent years, bone marrow as stem cell source has been replaced by peripheral blood stem cells, which results in faster engraftment. Cord blood grafts are increasingly used. Conditioning prior to transplant may be myeloablative or nonmyeloablative. The latter is used preferentially in patients with high age or organ impairment. Isolation in the hospital during posttransplant pancytopenia has been challenged by promising results using home care. PCR diagnosis and new antifungal and antiviral treatment have reduced morbidity and mortality. The major threat to a successful outcome after ASCT is leukemic relapse. PCR techniques to detect recipient cells in the leukemic cell lineage or minimal residual disease enable early detection of leukemic cells. Donor lymphocyte infusions have an antileukemic effect. ASCT has shown an antitumor effect in metastatic cancers from breast, kidney, colon, ovaries, prostate and pancreas. Mesenchymal stem cells may be derived from bone marrow and have the capacity to differentiate into several mesenchymal tissues, such as bone, cartilage and fat. They seem to escape the immune system and have immunomodulatory effects in vitro and in vivo. To conclude, ASCT is a potent immunotherapy.

Allogenic stem cell transplantation for nonmalignant disorders using matched unrelated donors

We here report 25 patients with nonmalignant disorders, ie, severe aplastic anemia (SAA, n = 12) or inborn errors of metabolism (IEM, n = 13), who underwent allogeneic hematopoietic stem cell transplantation (HSCT) from unrelated high-resolution typed HLA-A, -B, and -DRbeta1 identical donors. One patient had an HLA-B subtype-mismatched donor. Conditioning for SAA mainly consisted of cyclophosphamide and total body irradiation, and that for IEM consisted of busulfan and cyclophosphamide. All patients received antithymocyte globulin during conditioning. After HSCT, they were given cyclosporine combined with methotrexate for immunosuppression. Two patients rejected their grafts: 1 died of pneumonia, and the other was successfully regrafted. The cumulative incidence of acute graft-versus-host disease grades II to IV was 24%, whereas chronic graft-versus-host disease occurred in 21%. The 5-year survival rates were 83% in the SAA group and 85% in those with IEM. We conclude that HSCT with HLA-A, -B, and -DRbeta1 genomically matched unrelated donors in combination with antithymocyte globulin in the conditioning regimen gives encouraging results in patients with SAA or IEM.

Dose Study of Thymoglobulin During Conditioning for Unrelated Donor Allogeneic Stem-Cell Transplantation

BACKGROUND

Steroid-related bone loss is a recognized complication after renal transplantation. In a prospective, randomized, multicenter study we compared the influence of a steroid-free immunosuppressive regimen with a regimen with limited steroid exposure on the changes in bone mass after renal transplantation.

METHODS

A total of 364 recipients of a renal transplant were randomized to receive either daclizumab (1 mg/kg on days 0 and 10 after transplantation; steroid-free group n=186) or prednisone (0.3 mg/kg per day tapered to 0 mg at week 16 after transplantation; steroids group n=178). All patients received tacrolimus, mycophenolate mofetil, and, during the first 3 days, 100 mg prednisolone intravenously. Changes in bone mineral density (BMD) were evaluated in 135 and 126 patients in the steroid-free and steroids group, respectively.

RESULTS

The mean (+/- SD) BMD of the lumbar spine decreased slightly in both groups during the first 3 months after transplantation (steroid-free -1.3 +/- 4.0% [P<0.01]; steroids -2.3 +/-4.2% [P<0.01]). In the following months, lumbar BMD recovered in both groups (P<0.01), resulting in a lumbar BMD at 12 months after transplantation comparable with the baseline value. No difference between the groups was found at 3 months (steroid-free versus steroids +1.0%; 95% confidence interval -0.0%-+2.0%, P=0.060) and at 12 months after transplantation (steroid-free versus steroids +0.9%; 95% confidence interval -0.8%-+2.6%, NS).

CONCLUSION

The use of a moderate dose of steroids during 4 months after transplantation has no important influence on bone mass during the first year after renal transplantation. On average, both regimens prevented accelerated bone loss.

Which donor should be chosen for hematopoietic stem cell transplantation among unrelated HLA-A, -B, and -DRB1 genomically identical volunteers?

The aim of this study was to identify significant prognostic factors by using unrelated genomically HLA-A, -B and -DRB1-identical donors. Such data could help to choose the best donor. We studied 136 consecutive patients with hematologic malignancies and a median age of 32 years (range, 0-55 years) who received hematopoietic stem cell transplantation. Bone marrow grafts were given to 83 and peripheral blood stem cells to 53 patients. The cumulative incidence of grade II to IV acute graft-versus-host disease (GVHD) was 30% and of chronic GVHD was 54%. At 5 years, the overall transplant-related mortality (TRM) was 34%, and patient survival was 50%. In Cox multivariate analysis, 32 potential risk factors were analyzed. Monoclonal antibody OKT-3 during conditioning was correlated with grade II to IV acute GVHD, chronic GVHD, and TRM. HLA-DP mismatch was associated with poor TRM and poor survival. Cytomegalovirus-seropositive patients with a seronegative donor had a decreased leukemia-free survival. Five-year TRM was 14% with no risk factor, 38% with 1 risk factor, and 87% with 2 risk factors. The 5-year survival was 72%, 48%, and 30% with 0, 1, and 2 risk factors, respectively. We concluded that unrelated hematopoietic stem cell transplantation may be improved if an optimal donor and immunosuppression are chosen.

Polyclonal anti-T-cell globulin as part of the preparative regimen for pediatric allogeneic stem-cell transplantation

To prevent graft rejection and graft-versus-host disease (GvHD) after allogeneic stem-cell transplantation (ASCT), 56 children were given polyclonal anti-T-cell globulin (ATG) as part of the conditioning regimen. Of the 56 children in the cohort, 27 had a non-malignant disease and 29 had different hematological malignancies. Eight were in first remission of leukemia and the remainder in later stages. Donors were in 16 cases a human leucocyte antigen (HLA)-identical sibling and in 40 a matched unrelated donor (MUD). The control group comprised 16 patients with an HLA-identical donor; the children in this group were not treated with ATG. Side-effects related to the ATG treatment occurred in 63% of the patients and included fever, chills, headache, dyspnoea, nausea/vomiting, body pain, fall in blood pressure, and transient respiratory arrest. Engraftment occurred in 55 (98%) of the ATG-treated patients at a median of 17 (11-27) days after ASCT. One rejection occurred at 23 days post-SCT. The probabilities of acute graft-versus-host disease (GvHD) of grades II-IV were 6% for patients with an HLA-identical donor, 12% for controls, and 26% for the MUD group. Chronic GvHD occured in 20%, 50%, and 50% of patients in the three groups, respectively. Transplant-related mortality rates at 100 days were 6%, 6%, and 7%, respectively. The 5-yr survival rate was 94% and 81% using sibling donors, with and without ATG respectively, and 53% using unrelated donors (p = 0.002). Disregarding donor type, among the ATG-treated patients 5-yr survival rates were 46% in patients with a malignant disease and 77% in non-malignant disorders. Relapse and relapse-free survival rates were 42% and 46%, respectively. Five out of 12 patients who showed an early full donor chimerism in the T-cell lineage developed acute GvHD of grades II-IV, compared to none out of 13 patients being mixed chimeras (p = 0.01). Hence, the use of polyclonal ATG as part of conditioning prior to ASCT in children is safe and the survival rate encouraging.

Long-term persistence of oligoclonal serum IgM repertoires in patients treated with allogeneic bone marrow transplantation (BMT)

Immunoglobulin gene rearrangements in patients treated with BMT have restricted repertoire diversity. Clonal variability remains low for 3 months and reconstitution of the humoral immune system appears to follow a wave-like pattern. In the present study we analysed serum IgM and IgG repertoires in 44 patients from 1 week to 3 years after transplantation. We applied a quantitative immunoblot technique in combination with a newly developed method for estimation of repertoire diversity in complex mixtures of antibodies. Our results demonstrate that 60% of BMT patients have severely reduced diversity in the IgM repertoire during and after the first year post-BMT, compared with healthy controls. In contrast, the majority of patients have a polyclonal IgG repertoire, similar to that of healthy controls. Serum IgM repertoires remain oligoclonal even though the serum concentration of total IgM is within normal range around 6 months post-BMT. During the first years after transplantation IgM as well as IgG repertoires are less diverse in patients receiving a BM graft from a sibling donor compared with those receiving a graft from an HLA-matched unrelated donor. Patients in the latter group show a higher incidence of infections and minor antigen mismatches which may promote the development of a diverse immunoglobulin repertoire post-BMT.

Low incidence of acute graft-versus-host disease, using unrelated HLA-A-, HLA-B-, and HLA-DR-compatible donors and conditioning, including anti-T-cell antibodies

BACKGROUND

Using unrelated bone marrow, there is an increased risk of graft-versus-host disease (GVHD).

METHODS

HLA-A-, HLA-B-, and HLA-DR-compatible unrelated bone marrow was given to 132 patients. The diagnoses included chronic myeloid leukemia (n=43), acute lymphoblastic leukemia (n=29), acute myeloid leukemia (n=27), myelodysplastic syndrome (n=4), lymphoma (n=3), myeloma (n=1), myelofibrosis (n=1), severe aplastic anemia (n=12), and metabolic disorders (n=12). The median age was 25 years (range 1-55 years). HLA class I was typed serologically, and class II was typed by polymerase chain reaction using sequence-specific primer pairs. Immunosuppression consisted of antithymocyte globulin or OKT3 for 5 days before transplantation and methotrexate combined with cyclosporine.

RESULTS

Engraftment was seen in 127 of 132 patients (96%). Bacteremia occurred in 47%, cytomegalovirus (CMV) infection in 49%, and CMV disease in 8%. The cumulative incidences of acute GVHD > or = grade II and of chronic GVHD were 23% and 50%, respectively. The 5-year transplant-related mortality rate was 39%. The overall 5-year patient survival rate was 49%; in patients with metabolic disorders and severe aplastic anemia, it was 61% and 48%, respectively. The disease-free survival rate was 47% in patients with hematological malignancies in first remission or first chronic phase and 38% in patients with more advanced disease (P=0.04). Acute GVHD was associated with early engraftment of white blood count (P=0.02). Poor outcome in multivariate analysis was associated with acute myeloid leukemia (P=0.01) and CMV disease (P=0.04).

CONCLUSION

Using HLA-A-, HLA-B-, and HLA-DR-compatible unrelated bone marrow and immunosuppression with antithymocyte globulin, methotrexate, and cyclosporine, the probability of GVHD was low and survival was favorable.

Allogeneic bone marrow transplantation for hematological malignancies--controversies and recent advances

Today more than 80000 allogeneic bone marrow transplantations (BMT) have been performed worldwide. The major indications are hematological malignancies such as acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), chronic myeloid leukemia (CML) and myelodysplastic syndromes. Unrelated donors are increasingly used and there are around 4 million volunteer donors available in different registers, the largest being the National Marrow Donor Program. Molecular typing has improved the typing technique which has resulted in a decreased risk of graft-versus-host disease (GVHD), lower transplant-related mortality (TRM) and improved leukemia-free survival (LFS). Using HLA-identical siblings, patients with AML in first complete remission (1 CR) and high-risk ALL in 1 CR are clear indications for BMT. However, if an HLA-identical sibling is not available, it is not known today if an unrelated bone marrow or autografting is the best option for all patients with acute leukemia in 1 CR. Because BMT is the only curable treatment for CML, a search for an unrelated donor should start as soon as it is evident that an HLA-identical sibling is not available. BMT within a year from diagnosis is of major importance for outcome. Allogeneic peripheral blood progenitor cells (PBPC) have been used as an alternative to bone marrow. Preliminary studies indicate a faster engraftment, but prospective randomized trials are necessary to establish the role of allogeneic PBPC. Umbilical cord blood has also been used as a source of allogeneic hematopoietic stem cells. Using cord blood from HLA-identical siblings, engraftment seems to be delayed, but the probability of GVHD is low. Preliminary data using unrelated cord blood cells are encouraging. GVHD has an important antileukemic effect. Recently, a graft-versus-myeloma and a graft-versus-breast-cancer effect has been demonstrated. In patients who relapse after BMT, donor lymphocytes can induce remission, especially in patients with CML. With molecular techniques it is possible to detect relapse at an early stage, so called minimal residual disease. Liposomal amphotericin B has few side-effects and decreased the death rate by invasive fungal infection in BMT recipients. Early diagnosis and treatment of cytomegalovirus (CMV) infection with new antiviral drugs have dramatically reduced the incidence and mortality in CMV disease. Cyclosporine combined with methotrexate is today the most widely used immunosuppressive regimen and has decreased GVHD and improved survival. However, several new immunosuppressive drugs need to be explored in clinical BMT. Immune modulation by for instance cytokines and cytokine inhibititors is a new exciting development.