Unrelated Cord Blood Stem Cell Transplantation Research Articles

Successful Reduced-Intensity Stem Cell Transplantation From Unrelated Cord Blood In Three Patients with X-Linked Severe Combined Immunodeficiency.

AbstractAbstract 4571Severe combined immunodeficiency (SCID) is the most severe form of the primary immunodeficiencies (PID), the most frequent type of which is X-linked SCID (X-SCID; T-B+NK-SCID). Hematopoietic stem cell transplantation (SCT) is the only curative treatment for these high-risk patients. Recently, some PID cases treated with unrelated cord blood stem cell transplantation (CBT) have been reported. To avoid severe infection during SCT and late complications, such as mental and growth retardation, reduced-intensity conditioning (RIC) regimens have been used for unrelated SCT for PID patients. However, reports of X-SCID patients receiving CBT with reduced-intensity stem cell transplantation (RIST) are quite limited. We report successful allogenic RIST from unrelated cord blood (CB) for treatment of X-SCID in our single centre. Three patients with X-SCID who had no HLA-matched sibling received unrelated CBT. Mutations in the common gamma chain gene were detected in all patients. Pre-transplantation conditioning for all patients consisted of fludarabine (FLU) (30 mg/m2/day) from day -7 to day -2 (total dose 180 mg/m2) and busulfan (BU) 4 mg/kg/day from day -3 to day -2 (total dose 8 mg/kg). All CB units were serologically matched HLA-A, B, and DR loci. Though two of the patients suffered from fungal or bacterial pneumonia before transplantation, there were no additional infectious complications during transplantation. All patients achieved engraftment with an absolute neutrophil count > 500/μ l with a mean of 22 days (range, 19–27 days), and they showed 100% donor chimerism by fluorescence in situ hybridization of their peripheral mononuclear cells using × and Y chromosome probes at one-year post transplantation. Full donor chimerism of both T and B cells was also confirmed. Only one patient (patient 2) developed grade III acute graft versus host disease (GVHD), which resolved with increased oral corticosteroid. None of the patients have developed chronic GVHD, received intravenous immunoglobulin replacements after the transplantations, or showed delayed psychomotor development during 21 to 77 months of follow-up. Only one patient (patient 3) had short stature (-2.4SD) at 21-month follow-up. The most commonly used RIC regimens worldwide have been the FLU/melphalan (LPAM) and the FLU/BU regimens. LPAM has broad stem cell toxicity to both primitive and committed stem cells, while BU may spare committed stem cells, resulting in early onset and a prolonged duration of neutropenia with the FLU/LPAM regimen. Moreover, it has been reported that the LPAM-containing conditioning regimen is a risk factor for hepatic veno-occlusive disease. Although conditioning regimens including standard-dose BU may be associated with a high rate of treatment-related complications due to organ toxicity, reduced-dose BU in combination with FLU is less myelosuppressive and less toxic than the FLU/LPAM regimen. Moreover, CBT has some advantages with regard to incidence and intensity of GVHD and availability compared with other alternative stem cell sources. Patients 1 and 2 had overcome pre-existing fungal and bacterial pneumonias, respectively, and recovered after transplantation. Thus, immediate SCT using an RIC regimen could be indicated for patients with X-SCID to reconstitute the immune system regardless of pre-existing infections. Since pre-existing infections are the principal risk factors for poor SCT outcomes, early diagnosis and transplantation before any infectious episodes is necessary for X-SCID patients. In conclusion, CBT is a suitable alternative to bone marrow transplantation for X-SCID patients requiring urgent SCT with no sibling donors. RIC consisting of FLU and BU is an effective and safe treatment for such cases. Disclosures:No relevant conflicts of interest to declare.

Predominant Reconstitution of B Lymphoid Precursors (Hematogones) Following Unrelated Cord Blood Stem Cell Transplantation.

Primary B lymphoid lineages development from hematopoietic stem cells occurs in the bone marrow. During their development, B lymphoid precursors progress through a series of distinct developmental stages defined by CD34+CD38+CD10+CD19−Lin− early-B cells, CD34+CD38+CD10+CD19+Lin− pro-B cells, and CD34−/loCD38+CD10−CD19+CD20+ pre-B cells. These immature B lymphoid cells are more prominent in pediatric bone marrow, and the number of B lymphoid precursors is gradually declined with aging. Benign immature B lymphoid cells, originally termed hematogones, can be observed in the bone marrows during hematopoietic recovery phase in some patients who received chemotherapy or allogeneic bone marrow transplantation (allo-BMT) for hematologic disorders. However, little is known about the mechanisms of occurrence of hematogones and no study concerning hematogones has been available following unrelated cord blood stem cell transplantation (UCBT). We retrospectively analyzed populations of B lymphoid precursors of bone marrow samples from 67 patients who received allogeneic stem cell transplantation (SCT). Patients studied included 28 women and 39 men, with a median age of 49 years (19–66 years). The underlying diseases of 67 patients varied; 26 acute myelogenous leukemia, 10 acute lymphocytic leukemia, 3 chronic myelogenous leukemia, 10 myelodysplastic syndrome, 14 malignant lymphoma, and 4 others. 46 patients underwent allo-BMT and 21 underwent UCBT. Mean number of the infused cells amounted of 2.74 x 108 cells/kg (0.92–4.02 x 108) for allo-BMT recipients and 2.66 x 107 cells/kg (1.92–5.00 x 107) for UCBT recipients. 44 patients received myeloablative conditioning regimen (total body irradiation/cyclophosphamide for 32 patients and buslfan/cyclophosphamide for 12) and 23 received reduced intensity conditioning regimen. Graft-versus-host disease (GVHD) prophylaxis included 2 cyclosporine (CSP) alone, 3 CSP and mycophenolate mofetil, 18 CSP and methotrexate, 2 tacrolimus alone, and 42 tacrolimus and methotrexate. Median time between day 0 of transplant and days performed on evaluation of hematogones by bone marrow aspiration was 31 days (15–140 days). At that time, engraftment of donor cells was confirmed by chimerism analysis using DNA amplification of polymorphic short tandem repeats of bone marrow cells, indicating that hematogones were proven to derive from donor-origins. Hematogones were identified averagely in 1.65% of bone marrow cells (0.01–12.27%) for allo-BMT recipients and 8.39% (0.15–55.56%) for UCBT recipients, respectively. Furthermore, UCBT recipients disclosed more prominent expansion of hematogones than allo-BMT recipients; 5 out of 21 (23.8%) UCBT recipients and 3 out of 46 (6.5%) allo-BMT recipients presented 5% or more of hematogones in their bone marrow cells. These results indicated that UCBT recipients presented much higher frequency and prominent reconstitution of hematogones compared with allo-BMT recipients (p=0.0035). We next analyzed the proportion of hematogones by comparing donors' age with recipients' age, since B lymphopoiesis is associated with aging under the physiologically condition. Donor's age for UCBT was defined as 0-year-old for analyses. Donors for allo-BMT included 15 women and 31 men, with a median age of 36 years (17–66 years). Frequency of hematogones following SCT significantly declined with increasing the donors' age (p=0.0014), but not with increasing the patients' age. There was no statistically significant relationship between the number of hematogones and patients' sex, underlying disease, infectious complications, conditioning regimen, and serum level of immunoglobulin following transplantation. In conclusion, predominant reconstitution of hematogones can be detected following UCBT much higher than allo-BMT, indicating that reconstitution of hematogones depends on donor's age rather than recipient's age. These findings obtained from allogeneic SCT suggest that primary lymphoid development may depend on the intrinsic property of stem cells and progenitors, especially aging, rather than bone marrow microenvironments. For the patients who underwent SCT, hematogones often can be confused with relapse of their disease. Our study indicated that prudent attention should be taken in UCBT recipients as well as BMT recipients, although clinical significance of expanded hematogones has not yet resolved.

KIR-Ligand Incompatibility in the Graft-Versus-Host Direction Is Associated with Better Outcomes after Unrelated Cord Blood Stem Cell Transplantation for Acute Leukemia in Complete Remission

HLA class I, killer-cell immunoglobulin-like receptor (KIR) ligands which are missing in the recipient may trigger cytotoxicity of donor NK cells leading to graft-versus- host disease (GvHD) and/or graft-versus-leukemia reactions. Donor KIR(-ligand) incompatibility in the graft-versus-host (GvH) direction is associated with decreased relapse incidence (RI) and improved disease-free survival (DFS) in haplo-identical and HLA-mismatched unrelated hematopoietic stem cell transplantation (HSCT). Since it is unknown whether KIR-ligand mismatching impacts outcomes in unrelated cord blood stem cell transplantation (UCBT), we studied patients reported to Eurocord Registry with acute leukemia in complete remission (CR) with available high resolution typing of HLA-A, -B and -C in recipient/donor pairs who received a single UCBT. Patients and donors were categorized to their KIR-ligand groups by determining whether or not they expressed: HLA-C group 1 or 2, HLA-Bw4 and HLA-A3 or -A11. A total of 218 patient-donor pairs met the eligibility criteria. The patients had ALL (n=124) or AML (n=94) and were transplanted in 1st CR (n=105), 2nd CR (n=91) or >2nd CR (n=22). Median age was 13.4 yrs, weight 49 kg, and nucleated cell dose infused was 3.0×10E7/kg. The cord blood was HLA identical (6/6) in 21, 5/6 in 91, 4/6 in 91 and <4/6 in 15. Conditioning was myeloablative (84%) or reduced intensity (16%), and included ATG in 80%. Forty-one donors were HLA-C, 12 HLA-Bw4 and 22 HLA-A3/-A11 KIR-ligand mismatched in the GvH direction with the patient whereas fifty-one patients were HLA–C group 1 or 2, 19 HLABw4 and 18 HLA-A3/-A11 KIR-ligand mismatched in the HvG direction with the donor. When studying only donor-patient pairs in the GvH direction a total of sixty-nine patients had a KIR-ligand mismatched (KIR+) donor and 149 had not (KIR−). There were no statistical differences for patient-, disease- and transplantion-related factors between the KIR+ and KIR− group, except for more cytogenetically bad risk AML patients in the KIR+ group. HLA-C group 1 and 2, and HLA-A3/-A11, KIR-ligand incompatible UCBT showed independently a trend to improved DFS (p=0.09 and p=0.13, respectively). Analysis of the combined HLA-A, -B and -C KIR-ligand (mis)matches showed no statistical association with neutrophil recovery (81±4% KIR+, 79±3% KIR− group, p=0.21), non-relapse mortality (25±6% KIR+, 32±4% KIR−, p=0.34), acute GvHD (27±5% KIR+, 29±3% KIR−, p=0.82) and chronic GvHD (18±4% KIR+, 14±3% KIR−, p=0.38). However, differences were shown in RI (20±6% KIR+, 37±4% KIR−, p=0.03), DFS (55±7% KIR+, 31±4% KIR−, p=0.005) and overall survival (57±7% KIR+, 40±4% KIR−, p=0.02). In multivariate analysis, donor KIR-ligand incompatibility was associated with decreased RI (HR=0.53, p=0.05), increased DFS (HR=2.05, p=0.016) and overall survival (HR=2, p=0.004). In subgroup analysis for AML: RI for KIR+ vs KIR− was 5±4% vs 36±7% (p=0.005) and DFS 73±10% vs 38±7% (p=0.012); and for ALL: RI was 29±8% vs 37±6% (p=0.71) and DFS 44±9% vs 27±6% (p=0.10), respectively. The use of KIR-ligand incompatible donors in UCBT resulted in a lower RI and increased DFS and overall survival, especially in AML. If these results are confirmed in a larger series of patients KIR-ligand incompatibility in the GvH direction might be considered as a criterion of cord blood donor choice.

Unrelated Versus Related Donors Cord Blood Transplantation for Children with Non-Malignant Hematologic Diseases.

Allogeneic umbilical cord blood stem cell transplantation (CBT) has been accepted worldwide for curative therapy of many serious hematologic disorders for nearly two decades. To evaluate efficacy and outcomes of unrelated versus related donor CBT in Thai children with non-malignant diseases and to assess feasibility of using cord blood (CB) units cryopreserved in Thai National Cord Blood Bank, we retrospectively reviewed all children undergoing such transplants in our institute from February 2002 to July 2006. There were eligible 11 patients categorized into unrelated group (n=4, 3 male and 1 female) and related donors group (n=7, 6 male and 1 female). Median age and weight were 4 years 9 months (range 1 year 3 months-11 years 9 months), 17.3 kg (range 7.8–55 kg) and 7 years (range 1 year 6 months-14 years 10 months), 19.6 kg (range 13.1–30 kg), respectively. There were 2 cases of β-thalassemia/hemoglobin E, 1 of Wiskott-Aldrich syndrome (WAS), and 1 of severe aplastic anemia (SAA) in unrelated donors group, while every case in related group was diagnosed β-thalassemia/hemoglobin E. 4 unrelated donors consisted of 2 one-HLA-A-allele, 1 one-HLA-B-antigen, and 1 two-HLA-A-B-antigen mismatched cord blood units, while 7 related donors consisted of 5 HLA-identical, 1 two-allele mismatched, and 1 haploidentical siblings. Myeloablative conditioning regimen consisted of busulfan, cyclophosphamide, and anti-thymocyte globulin (ATG) for WAS and thalassemia patients. Fludarabine, ATG, and melphalan were used for the SAA girl because of precedent multiple transfusion received. Cyclosporine was used as graft-vs-host disease (GvHD) prophylaxis in every case. Median numbers of infused mononuclear cells and CD34+ cells of the unrelated donors group were 3.3×107/kg (range 2.4–44) and 2.75×105/kg (range 2.26–25), compared to 1.9×107/kg (range 1.5–3.4), and 1.06×105/kg (range 0.2–5.3) of the related group. Median times to neutrophil and platelet engraftments in each group were 15 and 37 days, compared to 22 and 43 days, respectively. 6 complete donor engraftments were achieved from 3 unrelated CB units and from 3 related sibling donors, however 2 mixed-chimerism status with donor predominance were present from related group. The remaining 1 case of the unrelated group and 2 of the related group did not engrafted, subsequently one case (thalassemia) resumed autologous recovery and unfortunately two cases (thalassemia and SAA) died due to neutropenic septicemia. Acute GvHD occurred in 2 unrelated (skin, gut, liver involvement grade IV (n=1); skin, gut grade II (n=1)) and 1 related (skin involvement grade II) CBT recipients. After immunosuppressive therapy the GvHD lesions were completely resolved in all but one thalassemia boy who suffered from severe fatal grade IV GvHD and eventually died. Median follow-up time for surviving patients was 30 months (range 4–53). Overall and disease-free survival in unrelated donor CBT (n=4) recipients were 50% (n=2) and 50% (n=2), compared to in related donor (n=7) 85.71% (n=6) and 71.43% (n=5), respectively. To date the boy with WAS has been cured by unrelated CBT for more than 4 years. Umbilical cord blood provides a reasonable option for source of hematopoietic stem cells to do transplantation for treatment non-malignant hematologic diseases and the outcome in our study is relatively well and comparable to other studies.

Successful Unmanipulated Haploidentical Bone Marrow Transplantation From an HLA 2-Locus-Mismatched Mother for Wiskott-Aldrich Syndrome After Unrelated Cord Blood Stem Cell Transplantation

The authors describe a boy with Wiskott-Aldrich syndrome (WAS) who was diagnosed immediately after birth using flow cytometric and genetic analysis. At 1 year of age he received unrelated cord blood stem cell transplantation (UCBSCT); however, the sex chromosomes of the peripheral blood mononuclear cells showed that the recipient type was over 70%. This rate gradually increased to over 90% after immunosuppressant therapy was discontinued. Clinical manifestations, including high fever, graft-versus-host disease (GVHD)-like eruptions, and signs of infection recurred. Results of flow cytometric and genetic analysis of mononuclear cells from the boy's mother were normal with no mutation. Three months after UCBSCT, he received an unmanipulated HLA-haploidentical 2-locus-mismatched bone marrow transplant (BMT) from his mother. The prophylaxis against GVHD was tacrolimus and short-term methotrexate. Hematopoietic reconstitution was rapid and fluorescence in situ hybridization analysis revealed sustained engraftment. Grade II acute GVHD developed but improved rapidly with the administration of methylprednisolone. The patient is progressing well and displays complete chimerism 2 years after the BMT. This case suggests that unmanipulated haploidentical BMT from the mother might be feasible not only for malignant disease but also for immunodeficiency disease patients who urgently need stem cell transplants and have no HLA-identical donors.

Kinetics of T-cell development of umbilical cord blood transplantation in severe T-cell immunodeficiency disorders

Background: Hematopoietic stem-cell transplantation is the treatment of choice for severe primary T-cell immunodeficiencies. When an HLA-identical sibling donor is not available, an alternative donor stem-cell source is needed. In primary T-cell immunodeficiencies, T-cell–depleted HLA-haploidentical bone marrow transplantation has been particularly successful in reconstituting the T-cell immune system in many of the severe combined immunodeficiency syndrome types. However, there are some problems associated with this preparation as a stem donor source, such as increased resistance to engraftment, a long period of time for T-cell engraftment to occur, and failure to engraft B cells and B-cell functions. These problems can be especially troublesome if the patient is infected before the transplantation. Objective: Umbilical cord blood was evaluated as a stem-cell source for immune reconstitution in children with severe primary T-cell immunodeficiency disorders, such as severe combined immunodeficiency syndrome, reticular dysgenesis, thymic dysplasia, and combined immunodeficiency disease, when a matched sibling donor was unavailable. Methods: From January 1996 through July 1997, 6 children received unrelated cord blood stem-cell transplantation after a preparative regimen for the treatment of combined immunodeficiency diseases. The patients ranged in age from 2 weeks to 6 years. The cord blood units were 3 of 6 HLA antigen matches in 2 children, 4 of 6 HLA antigen matches in 3 children, and 5 of 6 HLA antigen matches in 1 child, with molecular HLA-DR mismatch in 3 of the children. Results: The average time for neutrophil engraftment (absolute neutrophil count, >500/mm 3) was 12 days (range, 10 to 15 days), and the average time for platelet engraftment (platelet count, >20,000/mm 3) was 36 days (range, 24 to 50 days). In a patient with reticular dysgenesis, the first transplant failed to engraft but fully engrafted after a second unrelated donor cord blood transplantation. Five of 6 patients exhibited grade I graft-versus-host disease (GvHD), although 1 child experienced grade IV skin and gut GvHD. Immunologic reconstitution demonstrated that cord blood stem-cell transplantation resulted in consistent and stable T-cell, B-cell, and natural killer–cell development. The kinetics of recovery of phenotypic expression and function of T cells occurred between 60 to 100 days and that of natural killer cells at approximately 180 days. B cells engrafted early, and a study of functional B-cell antibody responses revealed that 2 of 2 patients in whom intravenous immune globulin was discontinued have low detectable antibody responses to tetanus and diphtheria toxoid immunizations more than 1 year after the transplantation. Conclusions: Unrelated umbilical donor cord blood is an excellent source of stem cells for transplantation of children with immune deficiency disorders. Benefits include rapid and reliable recovery of immune function, low risk of GvHD, and low viral transmission rate. (J Allergy Clin Immunol 1999;103:823-32.)