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Query: UMLS:C0018133 (graft-versus-host disease)
 18,032 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mixed hemopoietic chimerism has the potential to correct genetic hemological diseases (sickle cell anemia, thalassemia) and eliminate chronic immunosuppressive therapy following organ transplantation. To date, most strategies require either recipient conditioning (gamma-irradiation, depletion of the peripheral immune system) or administration of "mega" doses of bone marrow to facilitate reliable engraftment. Although encouraging, many issues remain that may restrict or prevent clinical application of such strategies. We describe an alternative, nonirradiation based strategy using a single dose of busulfan, costimulation blockade, and T cell-depleted donor bone marrow, which promotes titratable macrochimerism and a reshaping of the T cell repertoire. Chimeras exhibit robust donor-specific tolerance, evidenced by acceptance of fully allogeneic skin grafts and failure to generate donor-specific proliferative responses in an in vivo graft-versus-host disease model of alloreactivity. In this model, donor cell infusion and costimulation blockade without busulfan were insufficient for tolerance induction as donor-specific IFN-gamma-producing T cells re-emerged and skin grafts were rejected at approximately 100 days. When applied to a murine beta-thalassemia model, this approach allows for the normalization of hemologic parameters and replacement of the diseased red cell compartment. Such a protocol may allow for clinical application of mixed chimerism strategies in patients with end-stage organ disease or hemoglobinopathies.
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PMID:Costimulation blockade, busulfan, and bone marrow promote titratable macrochimerism, induce transplantation tolerance, and correct genetic hemoglobinopathies with minimal myelosuppression. 1144 Nov 22

Bone marrow transplantation offers a potential cure for a number of childhood cancers, sickle cell anemia, and stabilization of a deteriorating and debilitating process in a number of metabolic disorders and leukodystrophies. Depending upon the disease, treatment prior to BMT, and natural history of the disease, BMT may increase the risk of neuropsychological toxicity for children undergoing BMT, or may actually improve their long-term neurodevelopmental outlook. The role of factors such as pre-BMT therapy, age at time of treatment, presence or absence of total body irradiation, and toxicities associated with GVHD are presented for consideration. A developmental model for understanding the emergence of neurocognitive effects of BMT is reviewed, and strategies for intervention are considered.
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PMID:Acute and long-term neurodevelopmental outcomes in children following bone marrow transplantation. 1148 61

The morbidity and mortality associated with sickle cell disease (SCD) is caused by hemolytic anemia, vaso-occlusion, and progressive multiorgan damage. Bone marrow transplantation (BMT) is currently the only curative therapy; however, toxic myeloablative preconditioning and barriers to allotransplantation limit this therapy to children with major SCD complications and HLA-matched donors. In trials of myeloablative BMT designed to yield total marrow replacement with donor stem cells, a subset of patients developed mixed chimerism. Importantly, these patients showed resolution of SCD complications. This implies that less toxic preparative regimens, purposefully yielding mixed chimerism after transplantation, may be sufficient to cure SCD without the risks of myeloablation. To rigorously test this hypothesis, we used a murine model for SCD to investigate whether nonmyeloablative preconditioning coupled with tolerance induction could intentionally create mixed chimerism and a clinical cure. We applied a well-tolerated, nonirradiation-based, allogeneic transplantation protocol using nonmyeloablative preconditioning (low-dose busulfan) and costimulation blockade (CTLA4-Ig and anti-CD40L) to produce mixed chimerism and transplantation tolerance to fully major histocompatibility complex-mismatched donor marrow. Chimeric mice were phenotypically cured of SCD and had normal RBC morphology and hematologic indices (hemoglobin, hematocrit, reticulocyte, and white blood cell counts) without evidence of graft versus host disease. Importantly, they also showed normalization of characteristic spleen and kidney pathology. These experiments demonstrate the ability to produce a phenotypic cure for murine SCD using a nonmyeloablative protocol with fully histocompatibility complex-mismatched donors. They suggest a future treatment strategy for human SCD patients that reduces the toxicity of conventional BMT and expands the use of allotransplantation to non-HLA-matched donors.
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PMID:A cure for murine sickle cell disease through stable mixed chimerism and tolerance induction after nonmyeloablative conditioning and major histocompatibility complex-mismatched bone marrow transplantation. 1186 3

The novel allogeneic transplant approach outlined in this chapter proposes the dual concepts that currently used intensive cytoreductive conditioning programs can be successfully replaced by nonmyeloblative immunosuppression and that stem cell grafts create marrow space for engraftment through subclinical GVH reactions. Immunosuppression can be conceptually divided into two parts, one targeted exclusively towards host cells before transplantation, and the other aimed at both host and donor T lymphocytes after transplantation. The resultant effect is to either establish mutual graft-host tolerance as reflected by stable mixed donor-host chimerism or accomplish complete donor chimerism. Preclinical studies have demonstrated the feasibility of this new approach in the context of MHC-identical transplants in young canines. Early data from the dog model of severe hereditary hemolytic anemia suggest that mixed chimerism can partially correct the phenotypic expression of disease, but that complete chimerism will be necessary to halt the continued hemolytic process of the host type minority red blood cell population. In contrast, mixed chimerism would be expected to correct disease manifestations of other severe hereditary red blood cell disorders such as sickle cell disease. The early results in human patients with hematological malignancies have demonstrated the feasibility of establishing hematopoietic engraftment using a nonmyeloblative conditioning regimen. Using this regimen, transplants were performed in the outpatient setting, and the need for transfusion support was minimal. Preliminary information suggests that mixed chimerism does not appear to be stable in this older patient population, with most patients progressing to full donor chimerism and a small minority rejecting. Complete disease responses and molecular remissions have been observed in a significant proportion of patients, suggesting that adoptive immunotherapy may not be necessary in most cases. However, in those patients that engraft with at least mixed chimerism and develop progression of the underlying malignancy, DLIs can be used for subsequent adoptive immunotherapy. The feasibility and safety of the outpatient approach for MHC-nonidentical transplantation has been demonstrated. Graft rejection appears to have been corrected by the addition of fludarabine to the nonmyeloablative conditioning regimen for the recipients of HLA-identical sibling allografts. Despite most recipients of MHC-nonidentical transplantation having sustained engraftment, some rejections have been observed. Studies are ongoing to identify the risk factors for rejection after unrelated HSCT to ensure uniform engraftment in future studies.
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PMID:Outpatient allografting in hematologic malignancies and nonmalignant disorders--applying lessons learned in the canine model to humans. 1190 97

Allogeneic bone marrow transplantation (BMT) from HLA-identical siblings is an accepted treatment for both thalassemia and sickle cell disease (SCD). However, it is associated with decided risk of both transplant-related mortality (TRM) and chronic graft-versus-host disease (GVHD). We analyzed 44 patients (median age, 5 years; range, 1-20 years) given an allogeneic related cord blood transplant for either thalassemia (n = 33) or SCD (n = 11). Thirty children were given cyclosporin A (CsA) alone as GVHD prophylaxis, 10 received CsA and methotrexate (MTX), and 4 patients received other combinations of immunosuppressive drugs. The median number of nucleated cells infused was 4.0 x 10(7)/kg (range, 1.2-10 x 10(7)/kg). No patient died and 36 of 44 children remain free of disease, with a median follow-up of 24 months (range, 4-76 months). Only one patient with SCD did not have sustained donor engraftment as compared with 7 of the 33 patients with thalassemia. Three of these 8 patients had sustained donor engraftment after BMT from the same donor. Four patients experienced grade 2 acute GVHD; only 2 of the 36 patients at risk developed limited chronic GVHD. The 2-year probability of event-free survival is 79% and 90% for patients with thalassemia and SCD, respectively. Use of MTX for GVHD prophylaxis was associated with a greater risk of treatment failure. Related CBT for hemoglobinopathies offers a good probability of success and is associated with a low risk of GVHD. Optimization of transplantation strategies could further improve these results.
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PMID:Related umbilical cord blood transplantation in patients with thalassemia and sickle cell disease. 1242 97

Hematopoietic cell transplantation (HCT) has been used for more 30 years for the treatment of selected malignant and nonmalignant diseases. Traditionally, HCT for hematological disorders has relied on myeloablative conditioning before HLA-identical sibling bone marrow transplantation to correct the underlying hematological defect. Most children with hematological diseases who are referred to HCT have features that portend significant morbidity and early mortality. Among SAA patients who have HLA-identical sibling donors, younger patients with profound pancytopenia might be considered early for HCT. For others who lack sibling donors, patients who receive HCT from alternate sources have generally failed one or more courses of intensive immunosuppressive therapy and remain transfusion-dependent, some with hemosiderosis, red cell alloimmunization, and platelet transfusion refractoriness [44,46,48]. Currently, HCT for SCD is generally restricted to those who have experienced a significant sickle-related complication such as stroke, recurrent acute chest syndrome, or recurrent painful episodes [7,13]. In contrast, most reserve HCT in thalassemia for younger, Lucarelli class I, good-risk patients who have HLA-identical sibling donors, and veer away from older, high-risk thalassemics for whom transplantation is a riskier clinical intervention. For groups such as young adults with thalassemia major, HCT might become more widely applicable if its toxicity was reduced. Several approaches undergoing development include reduced-intensity conditioning and attempts to prevent GVHD. New methods to reduce the intensity and toxicity of conditioning as well as to use highly purified stem cells with the reduction in graft versus host disease may allow for the use of matched unrelated donors or haploidentical donors. This would serve to provide potentially more children who could benefit from stem cell transplantation with donors. These advances will hopefully lead to benefits for the majority of children who lack HLA-identical donors.
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PMID:New approaches to hematopoietic cell transplantation for hematological diseases in children. 1243 Jun 22

Although hematopoietic stem cell transplantation has curative potential for selected patients with sickle cell disease (SCD), most patients who are eligible for transplantation do not have a suitable donor. Cord blood (CB) from a sibling could provide an alternative stem cell source that, while not as well established as marrow, may offer certain advantages for selected families. These potential advantages include low risk to the infant donor, the possibility that mismatched CB units from sibling donors may be acceptable for transplantation, prompt availability of a stored CB unit for transplant, and decreased risk of clinically significant graft-versus-host disease. When families with SCD (or other transplant-treatable condition) conceive a sibling, no comprehensive research resource exists to assist the family in collecting the new infant's CB. With support from the National Heart Lung and Blood Institute, we are developing a noncommercial research-based CB Banking Program specifically for medically indicated sibling donations. In preliminary experience, we have collected CB from 52 SCD families across 19 states. Of these, 2 CB units have thus far been used for transplantation and 9 others are HLA-identical. We conclude that a CB bank focusing on sibling-donations may be feasible, but further study is required to determine whether such a bank can collect CB units of sufficient quantity and quality to support controlled trials of sibling CB transplantation. Families with a specific medical need, such as those already caring for a child with SCD, should consider collecting sibling CB as part of comprehensive care if the opportunity becomes available.
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PMID:Sibling donor cord blood banking for children with sickle cell disease. 1267 40

We describe previously transfused patients with sickle cell disease (n = 6) and thalassemia (n = 1) who received nonmyeloablative hematopoietic stem cell transplantation (HCT) to induce stable (full or partial) donor engraftment. Patients were 3 to 20 years (median, 9 years) old. All 7 received pretransplantation fludarabine and 200 cGy of total body irradiation; 2 patients also received horse antithymocyte globulin. Patients received bone marrow (n = 6) or peripheral blood stem cells (n = 1) from HLA-identical siblings, followed by a combination of mycophenolate mofetil and cyclosporine or tacrolimus for postgrafting immunosuppression. After nonmyeloablative HCT, absolute neutrophil counts were <0.5 x 10(9)/L and <0.2 x 10(9)/L for a median of 5 days (range, 0-13 days) and 0 days (range 0-13 days), respectively. A median of 0 (range, 0-9) platelet transfusions were administered. No grade IV nonhematologic toxicities were observed. One patient experienced grade II acute graft-versus-host disease. Two months after transplantation, 6 of 7 patients had evidence of donor chimerism (range, 25%-85%). Independent of red blood cell transfusions, these 6 patients initially had increased total hemoglobin and hemoglobin A concentrations and a reduction of reticulocytosis and transfusion requirements. There were no complications attributable to sickle cell disease during the interval of transient mixed chimerism. However, after posttransplantation immunosuppression was tapered, there was loss of the donor graft, and all patients experienced autologous hematopoietic recovery and disease recurrence. One patient did not engraft. The duration of transient mixed chimerism ranged from 97 to 441 days after transplantation in patients 4 and 6, respectively, and persisted until immunosuppressive drugs were discontinued after transplantation. In summary, the nonmyeloablative HCT regimens described here produced minimal toxicity and resulted in transient donor engraftment in 6 of 7 patients with hemoglobinopathies. Although complications from the underlying hemoglobinopathies did not occur during the period of mixed chimerism, these results suggest that stable (full or partial) donor engraftment after nonmyeloablative HCT is more difficult to achieve among immunocompetent pediatric patients with hemoglobinopathies than among adults with hematologic malignancies, perhaps in part because recipients may have been sensitized to minor histocompatibility antigens of their donor by preceding blood transfusions.
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PMID:Results of minimally toxic nonmyeloablative transplantation in patients with sickle cell anemia and beta-thalassemia. 1293 Nov 21

The dramatic advances that have taken place in recent years in the care of sick and premature infants also have been matched by a similar increase in the use of blood transfusion therapy. Haematological features indicate that a newborn has a blood volume of 85-125 ml/kg the foetal haemoglobin is 60-85% and average Hb in full term infant is 18 gm/dl. By 2-3 months it falls to 11-12 g/dl the main cause of anemia are iron poor diet, weaning diets recurrent or chronic infections and hemolytic episodes in malarious areas. The red cells transfusions are usually top up transfusions, exchange transfusions, partial exchange transfusions. Top up- are for investigational losses and correction of mild degrees of anemias, upto to 5-15 ml/kg. They comprise 90% of all neonatal transfusions and are used in low birth babies in special care units for a maximum of 9-10 episodes. The walk in donor programs once popular are not much in vogue. The threshold for transfusion is 8-10 g/dl Hb for upto 5 weeks. Exchange transfusions are done for correction of anemia, removal of bilirubin, removal of antibodies and replacement of red cells. Ideally plasma reduced red cells that are not older than 5 days are used. It is prepared by removal of 120 ml of standard whole blood donation. The advantage of fresh cells is that hyperkalemia is avoided and good post transfusion survival acceptable red cell oxygen affinity. However it has to be screened for sickle cell disease and G6PD deficiency. Indications for exchange transfusion are kernicterus, neonatal hemolysis, G6PD deficiency, ARDS, neonatal sepsis, DIC and neonatal isoimmune thrombocytopaenia. Complications include over transfusion, perforation of major vessels, hypocalcaemia, citrate toxicity, hypothermia, hypoglycaemia, thrombocytopenia, necrotizing enterocolitis, GVHD, bacterial, viral infections. Partial exchange transfusions are done for symptomatic anemia, where Hb<10 g/dl, it is indicated in polycythemia and hyperviscosity syndromes. Exchange volume = Blood volume x (observed Hct-Desired HCt) divided observed Hct. Points to consider-there is weak expression of ABO antigens so particular care while grouping. Transfusing volumes should be 2-5 ml/kg/hour in paediatric bags of 50-100 ml with infusion devices. Platelet transfusion are indicated in neonatal throbocytopaenia, thrombocytopaenia due to sepsis, DIC, bacterial pathogens, CMV, TORCHS, Obstetric conditions such as pre eclampsia, intrauterine death abruption placenta birth injury hypoxia schock neonatal iso immune thrombocytopaenia and maternal ITP. Administration 1 RDE/pack per 2.5 kg single dose of fresh platelets less than 24hrs which contains 55 x 10(9) cells. This also contributes fresh plasma so is useful for coagulation defects also, though there is a risk of CMV and GVHD due to leucocyte contamination. Granulocyte concentrate; Gravity leucopheresis-1:8 ratio of 60 ml of 6% HES made to stand for 1hr.
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PMID:Component therapy. 1451 88

With improvements in the treatment of children with sickle cell disease (SCD), there has been a significant increase in the number of patients with SCD in adult hematology practice. Quality of life and life expectancy continue to be severely compromised in adult patients; hydroxyurea is the only treatment currently available that could reduce the severity and frequency of painful episodes. Allogeneic stem cell transplantation (SCT) has been offered to children with SCD as a curative option. We discuss the implications of new developments in the field of allogeneic SCT in the treatment of adult SCD patients in light of the experience derived from pediatric transplantation. These developments include innovations in the conditioning regimens, GVHD prophylaxis, and alternative donor SCT and their possible effect on adult SCD patients. Finally, we discuss a nonmyeloablative conditioning protocol for adult SCD patients and the eligibility criteria for adult SCD patients undergoing allogeneic transplantation.
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PMID:Will developments in allogeneic transplantation influence treatment of adult patients with sickle cell disease? 1475 76


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