Split chimerism after allogeneic bone marrow transplantation in Chediak-Higashi syndrome

Chediak-Higashi Syndrome (CHS) is a hereditary multiorgan disease associated with a lymphoproliferative disorder termed 'accelerated phase' (AP). As AP is often life-threatening, hematopoietic stem cell transplantation has been proposed as the only curative treatment for CHS. Here, we report a 1-year-old Japanese boy with CHS who received an HLA-matched unrelated BMT at the AP stage, which resulted in split chimerism. We evaluated the chimerism status of isolated leukocytes and found that only a limited population of T and NK cells was of donor origin and the majority of these and other hematopoietic cells was of host origin. Clinical outcome was successful, and the patient is currently alive and well, free of AP and serious infections more than 18 months after BMT.     

Prognostic value of hematopoietic chimerism in patients with acute leukemia after allogeneic bone marrow transplantation: a prospective study

Hematopoietic chimerism as a predictive marker for the relapse of acute leukemia after allogeneic BMT was evaluated in a prospective study. Monthly assays of hematopoietic chimerism were performed from peripheral blood samples by PCR amplification of short tandem repeats or amelogenin loci. Between December 1997 and June 1999, 33 patients enrolled and 30 were evaluable (two early deaths, one lack of informative bands for chimerism evaluation). There were 14 male and 16 female patients (15 AML and 15 ALL) with a median age of 31 years (range 16-46). Mixed chimerism (MC) was observed at least once in 14 of 30 patients (47%). There was no significant difference between 14 patients who showed MC (MC group) and 16 patients who did not show MC (complete chimerism (CC) group) in terms of age, sex, disease status at BMT, donor type, and the number of bone marrow cells infused. There was no significant difference in the neutrophil and platelet engraftment rates between the two groups. After a median follow up of 10.9 months (range 4.3-22.4), five patients in the CC group and two patients in the MC group relapsed (P = 0.27). All five patients who relapsed in the CC group maintained CC up to 1 month prior to clinical relapse. Our study demonstrated that the patients who showed MC post BMT did not have higher risk of relapse of acute leukemia when compared to patients who did not show MC. Sensitive PCR-based assays for hematopoietic chimerism applied on a monthly basis after allogeneic BMT could not predict relapse of acute leukemia.     

The analysis of leukemic relapse after allogeneic bone marrow transplantation]

This report presents the analysis of leukemic relapse of 52 patients who received allogeneic bone marrow transplantation between July 1984 and May 1990. Conditioning regimen consisted of TBI + CY and GVHD prophylaxis consisted of cyclosporin-A and methotrexate. The relapse ratios of chronic myelogenous leukemia (CML) (21 in chronic phase, 1 in accelerated phase, 1 in blastic crisis), acute nonlymphocytic leukemia (ANLL) (all 17 in 1st CR), acute lymphocytic leukemia (ALL) (all 12 in 1st CR) were 13%, 18%, 25%, respectively, and 3 year disease free survival (DFS) was as follows, CML 68%, ANLL 72%, ALL 49%. Regarding acute GVHD grading and chronic GVHD presence, 3 year DFS was as follows, acute GVHD 0 degree: 59%, I degree: 78%, II degree-IV degree: 53%, chronic GVHD (+): 82% GVHD (-): 77%. In our center leukemic relapse has been the major cause of death after BMT since 1984. Among 9 relapsed cases, one recurred more than 3 years after BMT, and another one got recurrent leukemia of donor origin.     

Natural history of mixed chimerism after bone marrow transplantation with CD6-depleted allogeneic marrow: a stable equilibrium

Mixed hematopoietic chimerism (MC) is a common finding after allogeneic bone marrow transplantation (BMT), but the natural history of this phenomenon remains unclear. To understand the evolution and the implications of this finding, we performed a prospective analysis of the development of mixed chimerism in 43 patients with hematologic malignancies who received bone marrow (BM) from human leukocyte antigen (HLA)-identical sibling donors. T-cell depletion in vitro with anti-T12 (CD6) monoclonal antibody and rabbit complement was used as the only method of graft-versus-host disease (GVHD) prophylaxis. Overall, MC was identified in peripheral blood (PB) and BM in 22 of 43 (51%) patients evaluated. MC was found by restriction fragment length polymorphism (RFLP) analysis in 21 of 40 (53%) patients, by cytogenetic analysis in 6 of 29 (21%) patients, and by red blood cell phenotyping in 4 of 9 (44%) patients. RFLP studies were performed at 0.5, 1, 3, 6, 9, and 12 months post-BMT and then every 6 months, and showed a high probability of developing MC in the first 6 months after BMT followed by stabilization after 12 months. Cytogenetic analysis was less sensitive in detecting MC. Once MC was detected after BMT, the percentage of recipient cells increased very slowly over more than 3 years of follow-up, and no patient reverted to complete donor hematopoiesis (CDH). Thus, recipient and donor cells remained in a relative state of equilibrium for prolonged periods that seemed to favor recipient cells over donor cells. Patient's disease, remission status, or intensity of the transplant preparative regimen did not influence the subsequent development of mixed chimerism. Early immunologic reconstitution was the only factor that correlated with the subsequent chimeric status of the patients. The percentage and absolute number of T3 (CD3) and T4 (CD4) positive cells at day 14 after BMT were significantly higher in the patients who maintained CDH but NK cell reconstitution was similar in both groups, suggesting that early reconstitution with T cells may play a role in preventing recovery of recipient cells after BMT. GVHD was also associated with maintenance of CDH, but the probability of relapse, survival, and disease-free survival was identical in patients with MC and CDH.     

Poor engraftment after allogeneic bone marrow transplantation: role of chimerism analysis in treatment and outcome

We analyzed the clinical course and risk factors of 18 patients with poor engraftment after allogeneic bone marrow transplantation (BMT), defined as absolute neutrophil count below 0.1 x 10(9)/l 28 days post-BMT. Significant risks associated with non-engraftment included HLA one antigen mismatch, BMT from matched unrelated donor, and a low dose of colony-forming units-granulocyte-macrophage (<10(4)/kg). Examined by a semiquantitative analysis of polymorphic microsatellite markers, donor DNA chimerism on day 28 was found to be predictive of treatment outcome. Seven patients had detectable donor DNA, varying from 43 to 100%. Five of them responded to granulocyte colony-stimulating factor (G-CSF) and achieved engraftment. Two were given further infusions of peripheral blood hematopoietic stem cells (PBSC) from the same donors, resulting in engraftment in one of them. Eleven patients had no detectable donor DNA, and none responded to G-CSF. Autologous regeneration occurred in six of these patients, four after infusion of backup marrow and two spontaneously. The remaining five patients died despite the administration of PBSC from the same or different donors. Regular monitoring of donor DNA chimerism is useful in the management of patients at high risk of poor engraftment.     

Origin of leukemic relapse after bone marrow transplantation: comparison of cytogenetic and molecular analyses

Leukemic relapse following bone marrow transplant (BMT) is generally due to the recurrence in recipient cells, but may rarely occur as a result of donor cell transformation. Donor cell relapse is generally identified using cytogenetic markers such as the sex chromosomes. Recently, molecular techniques have been used to identify the origin of bone marrow cells by their DNA restriction fragment length polymorphisms. We describe the case of a male pediatric patient who had a leukemic relapse 30 months following BMT from his sister. Both cytogenetic and molecular techniques were used to identify the origin of the leukemic relapse. Cytogenetic analyses indicated the absence of the Y chromosome and the presence of a donor cell type 9qh polymorphism, suggesting a donor cell relapse. Molecular analyses also indicated the absence of the Y chromosome but demonstrated the recurrence of recipient DNA markers from three other chromosomes, suggesting a recipient cell relapse. While the leukemic cell lineage cannot be definitively assigned in this case, our results suggest that caution must be exercised when assigning leukemic cell lineage following post-BMT relapse.     

Growth hormone accelerates immune recovery following allogeneic T-cell-depleted bone marrow transplantation in mice

OBJECTIVE: To test in a murine model whether recombinant human growth hormone can promote immune recovery after allogeneic T-cell-depleted bone marrow transplantation. MATERIALS AND METHODS: Lethally irradiated (8.5 Gy) BALB/c mice (H2(d)) were transplanted with 5 x 10(6) T cell-depleted bone marrow cells from C57BL/6 mice (H2(b)). Recipient mice were injected intraperitoneally with recombinant human growth hormone (20 microg/dose/day) or saline for the first 4 weeks after transplantation. These animals were followed for phenotypic and functional immune recovery. RESULTS: Administration of human recombinant growth hormone improved the CD4(+) T-cell counts in peripheral blood on day +14 (44+/-14 vs 33+/-7/microL blood, p<0.05) and day +21 (281+/-109 vs 187+/-76/microL blood, p<0.01) compared with the saline control. These differences were no longer significant by day +28 despite continued growth hormone administration. Similar effects were also observed on CD8(+) T cells and B220(+) B cells. The improvements in peripheral T-cell counts were at least partially as a result of enhanced thymopoiesis because there was an increase in total thymocytes after treatment with growth hormone. T-cell-depleted bone marrow recipients treated with growth hormone rejected the third-party grafts faster than those treated with saline control (median survival time: 20 days vs 26 days, p<0.05). CONCLUSIONS: These data demonstrated that recombinant human growth hormone can accelerate phenotypic and functional immune reconstitution following allogeneic T-cell-depleted bone marrow transplantation in mice.     

Mixed chimerism of erythro- and megakaryopoiesis following allogeneic bone marrow transplantation

Until now, studies on mixed chimerism (MCh) after allogeneic bone marrow transplantation (BMT) have predominantly focused on the B- and T-lymphocyte population, but not on distinct myeloid cell lineages like nucleated erythroid precursors and megakaryocytes. To evaluate the lineage-restricted MCh more explicitly in 10 patients with chronic myelogenous leukemia (CML), a quantitative analysis was performed on bone marrow biopsies following a sex-mismatched host/donor constellation. Techniques included immunophenotyping (antiglycophorin C, CD61) for the identification of erythro- and megakaryopoiesis and a simultaneously conducted genotyping with x- and y-chromosome-specific DNA probes. Normal bone marrow and specimens taken before BMT served as controls. Contrasting a total gender-dependent sex-typing in the latter samples in the early and late posttransplant period (up to 586 days), 3-9% erythroid precursors and about 16% megakaryocytes revealed a host-type origin. This significantly higher number of host megakaryocytes is explained by their polyploidy generating an increased probability to detect positive signals at a certain section level of the corresponding biopsies. A striking conversion of MCh to a recipient cell type was found in leukemic relapse with a more than 90% host-derived erythroid and megakaryocytic cell population in 4 patients approximately 643 days after BMT.     

Antibody-mediated marrow failure after allogeneic bone marrow transplantation

Marrow graft failure observed in association with histocompatibility differences between donor and recipient is often attributed to rejection mediated by host-derived cytolytic T lymphocytes. The data presented in this report indicate that persistent host antibodies specific for donor antigen may also mediate graft failure, either by antibody-dependent cell-mediated cytotoxicity (ADCC), or complement- mediated cytotoxicity. In the case of HLA Class I disparity, where all donor cells express the target antigen, the presence of alpha-donor antibody was associated with complete graft failure and death. In the case of ABO blood group antigen disparity, the presence of alpha-donor antibody resulted in erythroid hypoplasia. The latter cases proved informative insofar as they established that host antibodies could persist for more than 18 months after chemoradiotherapy and impair marrow function.     

Tolerance and chimerism and allogeneic bone marrow/stem cell transplantation in liver transplantation

The liver has particular tolerogenic properties that allow its spontaneous acceptance in some animal species.Liver structure is considered to favor a tolerogenic environment.The peripheral tolerance mechanisms also play a role in spontaneous tolerance to liver graft.In a clinical setting,the main challenge nowadays facing liver transplantation is minimization of immunosuppression with the goal of donor-specific tolerance.Mechanisms involved in tolerance to transplanted organs are complex and partly unknown.A significant mechanism in tolerance induction is chimerism.Chimerism can be induced through transplantation of allogeneic donor bone marrow/stem cells under appropriate host conditioning.This review focuses on the tolerance mechanisms in liver transplantation and highlights the role of chimerism and allogeneic bone marrow/stem cell transplantation in tolerance development.     

Developing an algorithm of informative markers for evaluation of chimerism after allogeneic bone marrow transplantation

Analysis of chimerism by polymerase chain reaction amplification of STR or VNTR has become a routine procedure for the evaluation of engraftment after allogeneic stem cell transplantation. Knowledge of the frequency of different STR or VNTR alleles in unrelated individuals in a population is useful for forensic work. In the context of HLA identical sibling bone marrow transplantation the informativeness of these markers needs to be evaluated. We evaluated five STRs (THO1, VWA, FES, ACTBP2, and F13A1) and 1 VNTR (APOB) for informativeness in stem cell transplants from HLA identical sibling donors. All four markers used individually allowed us to discriminate 20-56% of the patient donor pairs. Using a combination of all these markers along with a polymorphic marker in the beta-globin gene and the sex chromosome specific amelogenin marker, we were able to discriminate 99% of the patient donor pairs. We have established an algorithm for evaluating chimerism following HLA identical sibling donor transplants in the Indian population using molecular markers in 310 patients. Analysis of heterozygote frequencies in different populations is similar suggesting that this algorithm can be used universally for transplant centers to evaluate chimerism following allogeneic bone marrow transplantation.     

Hematopoietic donor chimerism and graft-versus-myeloma effect in relapse of multiple myeloma after allogeneic bone marrow transplantation

 A large group of patients relapsing after allogeneic bone marrow transplantation (BMT) have obtained remission after infusion of leukocytes from their original donor, suggesting a graft-versus-myeloma effect. However, side effects such as graft-versus-host disease and myelosuppression are severe, and sometimes fatal, complications of this therapeutic approach. Previously we demonstrated that patients with leukemia who lack donor hematopoiesis in relapse after BMT experience severe and lasting aplasia after infusion of donor leukocytes. In two patients – one with extramedullary and one with marrow relapse after a sex-mismatched transplantation – we analyzed hematopoietic chimerism by cell sorting and bone marrow cultures. CD34-positive cells, CD4-CD8-positive cells, committed progenitors, and LTC-IC were of donor origin, as demonstrated by two-color fluorescence in situ hybridization (FISH). Additionally, in relapse complete donor T-cell chimerism was seen. In contrast, plasma cells were of recipient origin in the patient who had a relapse in the bone marrow. Both patients were treated with infusions of donor leukocytes from their original donor. Neither patient suffered myelosuppression, and one achieved a stable complete remission. Received: February 26, 1999 / Accepted: April 14, 1999     

Hepatopulmonary syndrome after allogeneic bone marrow transplantation

A 10-year-old girl with aplastic anemia received an allogeneic bone marrow transplantation (BMT). Three years after an uneventful course apart from chronic graft-versus-host disease (GVHD) she presented with chronic hypoxemia, reduced diffusion capacity of the lungs, normal spirometric lung function and increased bilirubin and liver enzymes. Intrapulmonary vascular dilatations were demonstrated. Pulmonary complications after BMT may include a hepatopulmonary syndrome (liver disease, hypoxemia, intrapulmonary vascular dilatations).