Cyclophosphamide and antithymocyte globulin to condition patients with aplastic anemia for allogeneic marrow transplantations: the experience in four centers

Incidence and risk factors for secondary graft failure in uniformly treated patients with severe aplastic anemia receiving fludarabine and cyclophosphamide for conditioning and matched sibling bone marrow graft as stem cell source

BACKGROUND AIMS

Graft failure after allogeneic transplant for aplastic anemia is problematic. The risk of graft failure depends on multiple variables, including the preparative regimen, donor type, stem cell dose and source among other variables.

METHODS

We performed a retrospective analysis of patients with aplastic anemia who underwent matched-sibling allogeneic transplant at a single center.

RESULTS

We identified 82 patients who fit the inclusion criteria. One had primary graft failure and was excluded from this analysis. The recipient median age was 22 years. The donor median age was 23 years. The median time from diagnosis to transplant was 1.6 months. The median number of red cell transfusions before transplant was nine. The median number of platelet transfusions before transplant was 18. Thirteen patients developed secondary graft failure, with a cumulative incidence at 5 years of 16% and median time to develop secondary graft failure of 129 days. All patients engrafted with a median time for neutrophil engraftment of 19 days and a median time for platelet engraftment of 22 days. The survival of patients with or without secondary graft failure was not different. Major or bidirectional ABO incompatibility and older recipient age were statistically significantly associated with greater risk of secondary graft failure.

CONCLUSIONS

Secondary graft failure is a significant complication after allogeneic transplant for SAA. Identification of recipients at risk and mitigating the potential risks of this complication is warranted.

Human leucocyte antigen-matched related haematopoietic stem cell transplantation using low-dose cyclophosphamide, fludarabine and thymoglobulin in children with severe aplastic anaemia

When human leucocyte antigen-matched related donors are available, haematopoietic stem cell transplantation (HSCT) in children with severe aplastic anaemia (SAA) represents the standard of care. Cyclophosphamide (Cy) 200 mg/kg and anti-thymocyte globulin (ATG) are frequently administered, but to-date, no standard conditioning regimen exists. In this study, we investigated the efficacy of a unified HSCT conditioning protocol consisting of low-dose Cy 80 mg/kg, fludarabine and ATG. Data were reviewed from children aged ≤14 years with either acquired SAA or non-Fanconi anaemia inherited bone marrow failure syndrome (IBMFS) between 2011 and 2022 at various Saudi institutions. Graft-versus-host disease (GVHD) prophylaxis included mycophenolate mofetil and calcineurin inhibitors. HSCT was performed in 32 children (17 females and 15 males). Nine patients had deleterious mutations (two ERCC6L2, two ANKRD26, two TINF2, one LZTFL1, one RTEL1 and one DNAJC21). Four patients had short telomeres. All 32 patients engrafted successfully. At 3 years post-transplant, the event-free survival was 93% and overall survival was 95%. Two patients experienced secondary graft failure or myelodysplastic syndrome. A low probability of GVHD was observed (one acute GVHD II and one mild chronic GVHD). These data highlight how HSCT using low-dose Cy as part of a fludarabine-based regimen is safe and effective in SAA/non-Fanconi anaemia IBMFS.

Fludarabine/Cyclophosphamide Conditioning Regimen in Aplastic Anemia Patients Receiving Matched-Sibling Donor Transplant Is Non-inferior to ATG/Cyclophosphamide: A Single-Center Experience from Pakistan

The successful outcome of allogeneic hematopoietic stem cell transplant (HSCT) in aplastic anemia patients is driven by suitable donor selection, appropriate conditioning regimen, early intervention, and optimal supportive care after transplant. Pakistan, being a developing country, faces grave economic challenges due to meager health care budget; therefore, cost constraints remain the foremost impediment in optimizing transplant facilities for socioeconomically deprived patients. We conducted a single-center retrospective analysis of aplastic anemia patients (N = 130), who received matched sibling donor transplants from 2011 to 2019, treated with either fludarabine/cyclophosphamide (Flu/Cy) or antithymocyte globulin/cyclophosphamide (ATG/CY) conditioning regimen. Median age was 16 years (IQR, 11-20), and it ranged from 3 to 48 years. The median time from diagnosis to transplant was 3 months (IQR, 2 to 4), and it ranged from 1 to 8 months. The estimated overall survival (OS), relapse-free survival (RFS), and GvHD-free survival (GFS) were found to be 69.0%, 66.7%, and 64.3% in the ATG/Cy group while 76.1%, 72.7%, and 62.5% in the Flu/Cy group, respectively, after a median follow-up of 30 months (IQR, 8 to 55), and it ranged from 0 to 98 months for the study groups. The Flu/Cy regimen was well tolerated and was not associated with increased risk of GvHD. Hence, it may be an appropriate alternative conditioning regimen for developing countries with limited health care resources.

Design, synthesis, and pharmacological evaluation of sinomenine derivatives on rings A and C: Novel compounds screening for aplastic anemia targeting on cytotoxic T lymphocyte

Cytotoxic T lymphocyte (CTL), a key effector cell in aplastic anemia (AA) immune injury, is shown to be a potential target for AA drug therapy. However, there is no candidate for this target till now. Oriented by the inhibition activity of CTL and macrophage derived nitric oxide (NO), a series of novel sinomenine derivatives on rings A and C are designed, synthesized and screened. Among them, compound 3a demonstrates the best inhibitory activity on CTL with an IC₅₀ value of 2.3 μM, and a 97.1% inhibiton rate on macrophage NO production without significant cytotoxicity. Further, compound 3a exhibits substantial therapeutic efficacy on immune-mediated BM failure in AA model mice by improving the symptoms of anemia and the function of BM hematopoiesis, and shows more advantages in life quality improving than cyclosporine A (CsA). Its efficacy on AA at least partly comes from targeting on activated cluster of differentiation (CD)8⁺ T cell. Additionally, 3a also shows much less toxicity (LD₅₀ > 10.0 g/kg) than sinomenine (LD₅₀ = 1.1 g/kg) in preliminary acute toxicity assessment in mice, and has a low risk to inhibit hERG to cause cardiotoxicity. These results indicate that compound 3a merits further investigation for AA treatment by targeting on CTL.

Upfront Alternative Donor Transplant versus Immunosuppressive Therapy in Patients with Severe Aplastic Anemia Who Lack a Fully HLA-Matched Related Donor: Systematic Review and Meta-Analysis of Retrospective Studies, on Behalf of the Severe Aplastic Anemia Working Party of the European Group for Blood and Marrow Transplantation

Idiopathic aplastic anemia is a rare and life-threatening disorder, and hematopoietic stem cell transplantation (HSCT) from a matched sibling donor (MSD) is the standard treatment strategy for young patients. Alternative donor transplantation (ADT) from a matched unrelated donor or an HLA haploidentical donor is not commonly used in the frontline setting. This systematic review/meta-analysis was conducted to compare ADT as an upfront, rather than delayed, treatment strategy in the absence of an MSD to immunosuppressive therapy (IST) in severe aplastic anemia (SAA). We searched PubMed/MEDLINE and Embase (1998 to 2019) for studies that compared the outcomes of ADT with IST as upfront therapy in patients with SAA. We included studies with 5 patients or more in each arm. Studies that included patients with inherited forms of bone marrow failure syndromes were excluded. The primary outcome was the 5-year overall survival (OS) rate. Five studies met the inclusion criteria and were included in this meta-analysis. The pooled 5-year odds ratio (OR) for OS was statistically significant at 0.44 (95% confidence interval [CI], 0.23 to 0.85) in favor of upfront ADT. In addition, survival was compared between upfront ADT versus salvage ADT in 6 studies. The pooled 5-year OR for OS was statistically significant at 0.31 (95% CI, 0.15 to 0.64) in favor of upfront ADT. Although this analysis has some limitations, including the retrospective nature of the included studies, the lack of ethnic diversity, the predominantly pediatric population, and the relatively suboptimal IST regimen used in some of the studies, it indicates that upfront ADT is a potential alternative treatment option in young and pediatric SAA patients who lack an HLA identical sibling donor, particularly when optimal IST is not available. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Haploidentical BMT for severe aplastic anemia with intensive GVHD prophylaxis including posttransplant cyclophosphamide

Severe aplastic anemia (SAA) is a stem cell disorder often treated with bone marrow transplantation (BMT) to reconstitute hematopoiesis. Outcomes of related HLA-haploidentical (haplo) donors after reduced-intensity conditioning with intensive graft-versus-host disease (GVHD) prophylaxis including posttransplantation cyclophosphamide are presented here from 37 SAA, 20 relapsed/refractory (R/R), and 17 treatment-naïve (TN) SAA patients. Median follow-up is 32 months (90% confidence interval [CI], 29-44). The median age was 25 (range, 4-69) years. The median time to neutrophil recovery was 17 days (range, 15-88). Four of 37 patients (11%) experienced graft failure (GF). There was 1 primary GF of 20 patients in the R/R group and 3 of 17 in the TN group at 200 cGy (1 primary, 2 secondary), but none in the 10 patients who received 400 cGy total body irradiation. Two patients with GF succumbed to infection and 2 were rescued with second haplo BMT. The overall survival for all patients is 94% (90% CI, 88-100) at 1 and 2 years. The cumulative incidence of grade II-IV acute GVHD at day 100 is 11%. The cumulative index of chronic GVHD at 2 years is 8%. Similar results were seen in 10 SAA patients who received the identical nonmyeloablative regimen with posttransplant cyclophosphamide but matched donor transplants. Haplo BMT with posttransplant cyclophosphamide represents a potential cure in SAA, with all 20 R/R currently alive, disease-free, and with no evidence of active GVHD. Extending this approach to TN patients was associated with higher GF rates, but an increase in total body irradiation dose to 400 cGy was associated with durable engraftment without greater early toxicity. Nonmyeloablative haplo BMT in TN SAA could lead to a paradigm shift, such that essentially all patients can proceed quickly to safe, curative BMT. These trials were registered at www.cincialtrials.gov as #NCT02224872) and #NCT02833805.

Allogeneic hematopoietic stem cell transplantation in aplastic anemia: current indications and transplant strategies

Treatment options for newly diagnosed aplastic anemia (AA) patient includes upfront allogeneic hematopoietic stem cell transplant (HSCT) or immunosuppressive therapy (IST). With recent advances in supportive care, conditioning regimens and post-transplant immunosuppression the overall survival for HSCT approaches 70-90%. Transplant eligibility needs to be assessed considering age, comorbidities, donor availability and probability of response to immunosuppressive therapy (IST). Upfront HSCT should be offered to children and young adults with matched related donor (MRD). Upfront HSCT may also be offered to children and young adults with rapidly available matched unrelated donor (MUD) who require urgent HSCT. Bone marrow (BM) graft source and cyclosporine (CsA) plus methotrexate (MTX) as graft versus host disease (GVHD) prophylaxis are preferable when using anti-thymocyte globulin (ATG) based conditioning regimens. Alemtuzumab is an acceptable alternative to ATG and is used with CsA alone and with either BM or peripheral blood stem cells (PBSC). Cyclophosphamide (CY) plus ATG conditioning is preferable for patients receiving MRD transplant, while Fludarabine (Flu) based conditioning is reserved for older adults, those with risk factors of graft failure and those receiving MUD HSCT. For haploidentical transplant, use of low dose radiotherapy and post-transplant cyclophosphamide has resulted in a marked reduction in graft failure and GVHD.

Allogeneic hematopoietic stem cell transplantation for aplastic anemia with pre-transplant conditioning using fludarabine, reduced-dose cyclophosphamide, and low-dose thymoglobulin: A KSGCT prospective study

The optimal pre-transplant conditioning for aplastic anemia (AA) remains unclear. We performed a prospective study on allogeneic transplantation from a related or unrelated donor for adult patients with AA. We assessed whether reduced-dose cyclophosphamide (CY) could decrease toxicity while maintaining engraftment, and low-dose thymoglobulin could safely prevent graft-vs-host disease (GVHD). The pre-transplant conditioning regimen consisted of fludarabine 120 mg/m² , CY 100 mg/kg, and thymoglobulin 2.5 mg/kg with or without 2 Gy of total body irradiation. Twenty-seven patients with a median age of 36 years were analyzed. Sixteen patients received graft from related donors. The stem cell source was bone marrow in 26 patients. All of the patients but one, who died early, achieved neutrophil engraftment at a median of 19 days. Mixed chimerism was observed in six and five patients at days 30 and 90, respectively. Only one patient experienced secondary engraftment failure with complete donor-type chimerism. None of the patients developed severe acute GVHD. The cumulative incidence of chronic GVHD was 37.7% at 1 year. The overall survival rate was 96.3% at 1 year and 3 years. A high EB virus-DNA load was detected in one patient at days 60. No one developed EBV-lymphoproliferative disorder within a year. The results suggest that the conditioning regimen in this study was safe and effective. However, relatively high incidence of chronic GVHD needs further improvement.

Allogeneic Bone Marrow Transplants for Pediatric Severe Aplastic Anemia: Real-world Data comparing Matched Related and Unrelated Donors in a Developing Country. Retrospective study on behalf of the Pediatric Hematopoietic Stem Cell Transplant Working Group of the Brazilian Bone Marrow Transplantation Society (SBTMO) and the Brazil-Seattle Consortium (Gedeco)

In this study, we report on major MRD or URD BMT outcomes in pediatric patients with SAA in Brazil. This was a retrospective study, which included 106 patients ≤18 years old who received a first BMT for SAA. All patients received bone marrow as graft source from an MRD (n = 69) or a URD (n = 37). Conditioning regimen was non-myeloablative in 73.6% of cases, and GVHD prophylaxis comprised a calcineurin inhibitor plus methotrexate in 89.6% of patients. After a median follow-up of 4.5 years after BMT, 81 patients are alive, with a 4-year OS of 77% and no statistically significant difference between the MRD and URD groups (82% vs. 69%, respectively; P = .08). Grade III-IV aGVHD at 6 months and cGVHD at 2 years were observed in 8% and 14% of cases, respectively, and were not statistically different between the groups. Twenty-five (23%) patients died at a median of 2.9 months after BMT. Our study showed that 4-year OS after BMT was not statistically different between MRD and URD recipients. This study shows that the outcomes of pediatric patients transplanted for SAA with a URD in Brazil are approaching those of MRD transplants. In contrast, OS after MRD BMT was lower than we would expect based on previous reports. The wide range of preparatory regimens used by the study centers highlights the need for standardized protocols for these children. Our findings provide a benchmark for future studies focused on improving BMT outcomes in this setting in Brazil.

Mixed Chimerism and Secondary Graft Failure in Allogeneic Hematopoietic Stem Cell Transplantation for Aplastic Anemia

Mixed chimerism (MC) and/or secondary graft failure (SGF) with recipient- or donor-type chimerism is a major obstacle in allogeneic transplantation for aplastic anemia (AA). From a registry database in Japan, patients with AA age >15 years who underwent a first allogeneic bone marrow or peripheral blood stem cell transplantation between 2000 and 2014 and achieved engraftment were included in this study. MC that did not require either granulocyte-colony stimulating factor (G-CSF) or transfusion support (group 1), MC (not SGF) that required G-CSF and/or transfusion support (group 2), SGF with MC or complete recipient-type chimerism (group 3), and SGF with complete donor-type chimerism (group 4) developed in 26, 16, 19, and 17 patients, respectively. The overall median duration of follow-up for survivors was 1727 days. The overall survival (OS) was 90.4% at 1 year and 83.5% at 5 years in patients without MC or SGF (n = 340), which was not different from the OS in groups 1 and 2. However, inferior OS was observed in group 3 (1 year, 52.1%; 5 years, 52.1%) and group 4 (1 year, 82.4%; 5 years, 56.3%). In multivariate analyses, the use of fludarabine (Flu) and the absence of irradiation in conditioning were associated with the development of SGF with MC or complete recipient-type chimerism, and the use of Flu in conditioning was associated with SGF with complete donor-type chimerism. In conclusion, the use of Flu may affect the occurrence of SGF with both recipient-type and donor-type chimerism.

[Improved outcome by optimized conditioning regimens with an increased dose of cyclophosphamide in allogeneic peripheral blood stem cell transplantation for severe aplastic anemia]

Objective: To respectively analyze the impact of conditioning regimens with a dose-decreased cyclophosphamide (Cy) on the outcome in fully matched sibling donor (MSD) peripheral blood stem cell transplantation (PBSCT) for severe aplastic anemia (SAA) . Methods: Two conditioning regimens with different doses of Cy (150 mg/kg or 120 mg/kg) in combination with fludarabine (Flu) and antithymocyte globulin (ATG) for MSD-PBSCT were investigated in 51 patients with acquired SAA. Results: Overall survival and failure-free survival in patients received 150 mg/kg of Cy (Cy150 cohort) or 120 mg/kg (Cy120 cohort) were 93.5% vs 90.0% (χ(2)=0.170, P=0.680) and 90.3% vs 85.0% (χ(2)=0.285, P= 0.594) respectively. However, either acute or chronic graft-versus-host disease risks were higher in Cy120 cohort than in Cy150 cohort (HR=3.89, 95% CI 1.21-12.53, P=0.023; HR=4.48, 95% CI 1.40-14.32, P= 0.011, respectively) . No difference was found for opportunistic infections or graft failure between two cohorts. Conclusion: Cy at a dose of 150 mg/kg, in combination with Flu and ATG, was more effective than that of 120 mg/kg Cy to produce improved clinical outcome in the setting of acquired SAA patients after MSD-PBSCT.

Haploidentical Donor Bone Marrow Transplantation for Severe Aplastic Anemia

Hematopoietic stem cell transplantation (bone marrow transplantation [BMT]) is the only curative treatment of severe aplastic anemia. BMT from an human leukocyte antigen (HLA)-matched sibling donor is the standard of care for young patients; immunosuppressive therapy is used for older patients or those lacking matched sibling donors. Patients with refractory or relapsed disease are increasingly treated with HLA haploidentical BMT. Historically, haploidentical BMT led to high rates of graft rejection and graft-versus-host disease. High-dose post transplant cyclophosphamide, which mitigates the risk of graft-versus-host disease, is a major advance. This article provides an overview of the haploidentical BMT approach in severe aplastic anemia.

Allogeneic Matched Related Donor Bone Marrow Transplantation for Pediatric Patients With Severe Aplastic Anemia Using "Low-dose" Cyclophosphamide, ATG Plus Fludarabine

BACKGROUND

The combination of cyclophosphamide (CY) and antithymocyte globulin (ATG) has been used as a standard conditioning regimen for matched related donor transplantation in patients with severe aplastic anemia.

PROCEDURE

To decrease the regimen-related toxicity while maintaining appropriate engraftment and survival rates, fludarabine (FLU) was added to the regimen. Four pediatric patients received matched related donor bone marrow transplantation with CY (50 mg/kg×2) (instead of the 50 mg/kg×4 standard dosing), equine ATG (30 mg/kg×3), with the addition of FLU (30 mg/m×4). Graft versus host disease (GvHD) prophylaxis included a calcineurin inhibitor and methotrexate.

RESULTS

No grade 4 acute toxicities occurred during the first 30 days after transplant. All patients engrafted with normalization of peripheral blood counts and transfusion independence. One patient developed grade 1 to 2 acute GvHD, followed by chronic GvHD that resolved. With a median follow-up of 41.7 months, all 4 patients are alive and transfusion free, with complete donor chimerism. This combination of a low-dose CY/ATG+FLU regimen was overall very well tolerated and contributed toward a successful outcome including engraftment, chimerism, and survival.

CONCLUSION

This small pilot study shows that this cytoreductive regimen could be considered as the standard of care for transplantation of pediatric patients with aplastic anemia from HLA-matched siblings.

T Cell Receptor Profiling in Type 1 Diabetes

PURPOSE OF REVIEW

The genetic susceptibility and dominant protection for type 1 diabetes (T1D) associated with human leukocyte antigen (HLA) haplotypes, along with minor risk variants, have long been thought to shape the T cell receptor (TCR) repertoire and eventual phenotype of autoreactive T cells that mediate β-cell destruction. While autoantibodies provide robust markers of disease progression, early studies tracking autoreactive T cells largely failed to achieve clinical utility.

RECENT FINDINGS

Advances in acquisition of pancreata and islets from T1D organ donors have facilitated studies of T cells isolated from the target tissues. Immunosequencing of TCR α/β-chain complementarity determining regions, along with transcriptional profiling, offers the potential to transform biomarker discovery. Herein, we review recent studies characterizing the autoreactive TCR signature in T1D, emerging technologies, and the challenges and opportunities associated with tracking TCR molecular profiles during the natural history of T1D.

Alternative Donor Transplantation with High-Dose Post-Transplantation Cyclophosphamide for Refractory Severe Aplastic Anemia

Severe aplastic anemia (SAA) is a life-threatening hematopoietic stem cell disorder that is treated with bone marrow transplantation (BMT) or immunosuppressive therapy (IST). The management of patients with refractory SAA after IST is a major challenge. Alternative donor BMT is the best chance for cure in refractory SAA, but morbidity and mortality from graft failure and complications of graft-versus-host disease (GVHD) have limited enthusiasm for this approach. Here, we employed post-transplantation high-dose cyclophosphamide in an effort to safely expand the donor pool in 16 consecutive patients with refractory SAA who did not have a matched sibling donor. Between July 2011 and August 2016, 16 patients underwent allogeneic (allo) BMT for refractory SAA from 13 haploidentical donors and 3 unrelated donors. The nonmyeloablative conditioning regimen consisted of antithymocyte globulin, fludarabine, low-dose cyclophosphamide, and total body irradiation. Post-transplantation cyclophosphamide 50 mg/kg/day i.v. on days +3 and +4 was administered for GVHD prophylaxis. Additionally, patients received mycophenolate mofetil on days +5 through 35 and tacrolimus from day +5 through 1 year. The median age of the patients at the time of transplantation was 30 (range, 11 to 69) years. The median time to neutrophil recovery over 1000 × 103/mm3 for 3 consecutive days was 19 (range, 16 to 27) days, to red cell engraftment was 25 (range, 2 to 58) days, and to last platelet transfusion to keep platelets counts over 50 × 103/mm3 was 27.5 (range, 22 to 108) days. Graft failure, primary or secondary, was not seen in any of the patients. All 16 patients are alive, transfusion independent, and without evidence of clonality. The median follow-up is 21 (range, 3 to 64) months. Two patients had grade 1 or 2 skin-only acute GVHD. These same 2 also had mild chronic GVHD of the skin/mouth requiring systemic steroids. One of these GVHD patients was able to come off all IST by 15 months and the other by 17 months. All other patients stopped IST at 1 year. Nonmyeloablative alloBMT using post-transplantation cyclophosphamide allowed for safe expansion of the donor pool to include HLA-haploidentical donors. This approach appears promising in refractory SAA patients. Importantly, engraftment was 100%, pre-existing clonal disease was eradicated, and the risk of GVHD was low.

Evolving hematopoietic stem cell transplantation strategies in severe aplastic anemia

PURPOSE OF REVIEW

Significant improvements in unrelated donor hematopoietic stem cell transplantation (HSCT) in recent years have solidified its therapeutic role in severe aplastic anemia (SAA) and led to the evolution of treatment algorithms, particularly for children.

RECENT FINDINGS

Advances in understanding the genetics of inherited bone marrow failure syndromes (IBMFS) have allowed more confidence in accurately diagnosing SAA and avoiding treatments that could be dangerous and ineffective in individuals with IBMFS, which can be diagnosed in 10-20% of children presenting with a picture of SAA. Additionally long-term survival after matched sibling donor and matched unrelated donor HSCT now exceed 90% in children. Late effects after HSCT for SAA are minimal with current strategies, and compare favorably to late effects after upfront immunosuppressive therapy, except for patients with chronic graft versus host disease.

SUMMARY

Careful assessment for signs or symptoms of IBMFS, along with genetic screening for these disorders, is of major importance. Matched sibling donor HSCT is already considered the standard of care for upfront therapy and some groups are evaluating matched unrelated donor HSCT as primary therapy. Ongoing studies will continue to challenge treatment algorithms and may lead to an even more expanded role for HSCT in SAA.

Second allogeneic stem cell transplant for aplastic anaemia: a retrospective study by the Severe Aplastic Anaemia Working Party of the European Society for Blood and Marrow Transplantation

We analysed the outcome of a second allogeneic haematopoietic stem cell transplant (alloHSCT) in 162 patients reported to the European Society for Blood and Marrow Transplantation between 1998 and 2009. Donor origin was a sibling in 110 and an unrelated donor in 52 transplants, respectively. The stem cell source was bone marrow in 31% and peripheral blood in 69% of transplants. The same donor as for the first alloHSCT was used in 81% of transplants whereas a change in the choice of stem cell source was reported in 56% of patients, mainly from bone marrow to peripheral blood. Neutrophil and platelet engraftment occurred in 85% and 72% of patients, after a median time of 15 and 17 days, respectively. Grade II-IV acute graft-versus-host disease (GVHD) and chronic GVHD occurred in 21% and 37% of patients, respectively. Graft failure (GF) occurred in 42 patients (26%). After a median follow-up of 3·5 years, the 5-year overall survival (OS) was 60·7%. In multivariate analysis, the only factor significantly associated with a better outcome was a Karnofsky/Lansky score ≥80 (higher OS). We conclude that a second alloHSCT is feasible rescue option for GF in SAA, with a successful outcome in 60% of cases.

Allogeneic hematopoietic stem cell transplantation for non-malignant hematological disorders

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) from a geno-identical matched sibling (MSD) is one of the most successful therapies in patients with non-malignant hematological disorders. This study included 273 patients with severe aplastic anemia (SAA), 152 patients with B-Thalassemia major (BTM), 31 patients with Fanconi's anemia (FA), 20 patients with congenital immunodeficiency diseases (ID), and 13 patients with inherited metabolic disorders (IMD) allografted from a MSD. In SAA, the 8-year overall survival (OS) of the whole group patients was 74%. OS was significantly better in patients conditioned with fludarabine and cyclophosphamide (Flu/Cy) than in those who received cyclophosphamide and antithymocyte globulin (Cy/ATG) (p = 0.021). Acute graft-versus-host disease (aGVHD) grade II-IV occurred in 15% while chronic GVHD (cGVHD) occurred in 28%. In BTM, the 12-year disease-free survival (DFS) of the whole group of BTM patients was 72.4%. DFS was 74% for peripheral blood stem cell (PBSC) group compared to 64% in the BM stem cell group. The incidence of graft rejection was significantly lower in patients who received PBSC than in those who received BM (9% vs 25%) (p = 0.036). AGVHD grade II-IV and cGVHD occurred in 15% and 12% of the whole group of BTM patients respectively. In FA, the 5-year OS was 64.5%. Graft rejection occurred in 10% of patients. Grade II-IV aGVHD occurred in 16% while cGVHD occurred in 4%. In ID, the 5-year OS was 62%. Graft rejection occurred in two (10%) patients. Three patients (15%) developed grade II-IV aGVHD, 2 of them progressed to secondary cGVHD. In IMD, OS was 46% at 5 years. Graft rejection occurred in 8% of patients. AGVHD grade II-IV occurred in 15% while cGVHD occurred in 14%. In conclusion, Allo-HSCT provides a higher DFS rate over conventional therapies for patients with non-malignant hematological disorders with prolonged survival.

Outcomes of hematopoietic cell transplantation in adult patients with acquired aplastic anemia using intermediate-dose alemtuzumab-based conditioning

Graft-versus-host disease (GVHD) has no therapeutic benefit after hematopoietic cell transplantation (HCT) for patients with acquired aplastic anemia (AA), and its prevention is highly desirable. We designed a conditioning regimen using an intermediate dose of alemtuzumab (50 to 60 mg) and describe our institutional experience of 41 patients who underwent HCT for AA. The median age at HCT was 37 years (range, 17 to 59). The conditioning regimen was high-dose cyclophosphamide (n = 9) or fludarabine based (n = 32). Additional GVHD prophylaxis was with cyclosporine. With a median follow-up of 3.6 years, overall survival at 3 years was 85%. Survival in patients <40 years and ≥40 years was 96% and 67%, respectively (P = .04). Graft failure occurred in 4 (10%) patients; 2 primary and 2 secondary. The cumulative incidences of acute (grades 1 to 2) and chronic GVHD were 27% and 15%, respectively. No patients developed grade 3 to 4 acute GVHD or severe chronic GVHD. The following viral complications were frequent: cytomegalovirus reactivation (79%), herpes simplex (18%), varicella zoster (25%), and BK virus hemorrhagic cystitis (8%). The majority of patients had no significant long-term health issues. This intermediate-dose alemtuzumab-based conditioning regimen results in excellent survival with a favorable impact on GVHD and long-term health outcomes, but close monitoring for viral complications is important.

A combination of fludarabine, half-dose cyclophosphamide, and anti-thymocyte globulin is an effective conditioning regimen before allogeneic stem cell transplantation for aplastic anemia

Conditioning regimens consisting of reduced-dose cyclophosphamide (CY) and fludarabine (FDR) have been investigated for use in allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with aplastic anemia to reduce the toxicities associated with CY. However, the ideal dose of CY has not been identified. In addition, little information is available regarding donor cell chimerism after allo-HSCT with these regimens. Therefore, we retrospectively analyzed 13 patients who underwent allo-HSCT with half-dose CY (100 mg/kg in total), FDR, and anti-thymocyte globulin at total doses of 2.5-10 mg/kg at our center. All the patients except one, who died due to encephalopathy on day 20, achieved neutrophil engraftment a median of 18.5 days after HSCT with complete donor-type chimerism. Two patients who received a graft from an HLA-matched donor subsequently developed mixed chimerism (MC) associated with transfusion-dependent cytopenia. One became transfusion-independent after donor lymphocyte infusion, but continues to exhibit MC. The other regained complete donor-type chimerism after the cessation of cyclosporine, but remains transfusion-dependent. These findings suggest that a conditioning regimen with half-dose CY and FDR is effective for achieving neutrophil engraftment and complete donor-type chimerism. However, subsequent MC may be observed, especially after HLA-matched HSCT.

Different outcomes between cyclophosphamide plus horse or rabbit antithymocyte globulin for HLA-identical sibling bone marrow transplant in severe aplastic anemia

The standard regimen for HLA-identical sibling bone marrow transplant (BMT) in severe aplastic anemia (SAA) is cyclophosphamide (Cy) and horse antithymocyte globulin (ATG). Horse ATG has been replaced by rabbit ATG in many countries due to the unavailability of the former product. This study was designed to assess if these ATG preparations are interchangeable in the preparative regimen for matched related BMT in SAA. Forty consecutive BMTs were retrospectively analyzed: 20 received Cy plus horse ATG and 20 received Cy plus rabbit ATG as the preparative regimen. Conditioning with rabbit ATG was protective against acute graft-versus-host disease (aGVHD) grades II-IV and moderate-severe chronic GVHD (cGVHD), with incidence rates of 0% versus 35.2% (P = .009) and 0% versus 34.0% (P = .04), respectively. On day +100, the probability of proven/probable invasive fungal disease (IFD) was higher in patients conditioned with rabbit ATG, 31.2% versus 5.5%, respectively (P = .04). Earlier cytomegalovirus (CMV) reactivation (40 versus 50 days; P = .02) was observed with rabbit ATG. An inferior lymphocyte count on days +30 (0.360 versus 0.814 × 10(9)/L; P = .01) and +90 (0.744 versus 1.330 × 10(9)/L; P = .006) was noticed in recipients of rabbit ATG. The incidence of stable mixed chimerism was higher in recipients of rabbit ATG (18.2% versus 80%, respectively; P = .004). These results suggest that horse and rabbit ATG preparations have different biological and clinical properties and should not be used interchangeably in the preparative regimen for related BMT in SAA.

Success of allogeneic marrow transplantation for children with severe aplastic anaemia

Allogeneic marrow transplantation offers curative therapy for children with severe aplastic anaemia (SAA). We report the outcomes of 148 children with SAA who received human leucocyte antigen (HLA)-matched related marrow grafts between 1971 and 2010. Patients were divided into three groups, reflecting changes in conditioning and graft-versus-host disease (GVHD) prophylaxis regimens that occurred over time. Patients in Group 1 were conditioned with cyclophosphamide (CY; 200 mg/kg) followed by 'long' (102 d) methotrexate (MTX). Patients in Groups 2 and 3 received CY alone (Group 2) or combined with anti-thymocyte globulin (Group 3) followed by 'short' (days 1, 3, 6, and 11) MTX and ciclosporin (until day 180). With a median follow-up of 25 years, the 5-year survivals were 66%, 95%, and 100% for Groups 1, 2, and 3, respectively (overall P < 0·0001). The 3-year estimates of graft rejection were 22%, 32%, and 7%, respectively. The probabilities of grades III-IV acute and 2-year chronic GVHD were 15%, 0%, and 3%, and 21%, 21%, and 10%, respectively. Advances in preparative and GVHD prophylaxis regimens, and supportive care during the past 40 years have led to improved outcomes for children with SAA. These results confirm the use of allogeneic marrow transplantation for children with SAA who have HLA-matched related donors.

Long-term follow up after allogeneic stem cell transplantation in patients with severe aplastic anemia after cyclophosphamide plus antithymocyte globulin conditioning

BACKGROUND

Due to increased rates of secondary solid organ cancer in patients with severe aplastic anemia who received an irradiation-based conditioning regimen, we decided some years ago to use the combination of cyclophosphamide and antithymocyte globulin. We report the long-term follow up of patients who underwent hematopoietic stem cell transplantation from an HLA-matched sibling donor after this conditioning regimen.

DESIGN AND METHODS

We analyzed 61 consecutive patients transplanted from June 1991 to February 2010, following conditioning with cyclophosphamide (200 mg/kg) and antithymocyte globulin (2.5 mg/kg/day × 5 days).

RESULTS

Median age was 21 years (range 4-43); 41 of the 61 patients were adults. Median duration of the disease before hematopoietic stem cell transplantation was 93 days. All but 2 patients received bone marrow as the source of stem cells and all but 2 engrafted. Cumulative incidence of acute grade II-IV graft-versus-host disease was 23% (95%CI 13-34) and 18 developed chronic graft-versus-host disease (cumulative incidence 32% at 72 months, 95% CI 20-46). In multivariate analysis, a higher number of infused CD3 cells was associated with an increased risk of developing chronic graft-versus-host disease (P = 0.017). With a median follow up of 73 months (range 8-233), the estimated 6-year overall survival was 87% (95% CI 78-97). At 72 months, the cumulative incidence of avascular necrosis was 21% and 12 patients presented with endocrine dysfunction (cumulative incidence of 19%). Only one patient developed a secondary malignancy (Hodgkin's lymphoma) during follow up.

CONCLUSIONS

Cyclophosphamide and antithymocyte globulin is an effective conditioning regimen for patients with severe aplastic anemia and is associated with low treatment-related mortality. Long-term complications include avascular necrosis and endocrine dysfunction.

Favorable preliminary results using TLI/ATG-based immunomodulatory conditioning for matched unrelated donor allogeneic hematopoietic stem cell transplantation in pediatric severe aplastic anemia

To assess whether a tolerance-induction regimen could be applied for unrelated (MUD) HCT in SAA, we retrospectively reviewed our HCT experience using unmanipulated 10/10 HLA-matched bone marrow grafts from MSD vs. MUD donors. Conditioning was CTX 200 mg/kg (CTX) + rabbit ATG 10 mg/kg (ATG) for MSD (n = 9) and TLI (800 cGy) + CTX/ATG for MUD HCT ( n = 5). Immunoprophylaxis was CSA and short-course MTX. Median patient age was 14.7 yr, median time to HCT 1.5 yr, and median follow-up 3 yr. Outcome measures included EFS, time to engraftment, and cumulative incidence of GVHD (CIN of GVHD) for MSD and MUD cohorts. EFS and stable engraftment rate were 100%. CIN of acute GVHD was: MSD, Grade I-II: 1 (11%), Grade III-IV: 0%; MUD, Grade I-II: 1 (20%), Grade III-IV: 1 (20%). CIN of chronic GVHD was: MSD, limited: 1 (11%), extensive: 0%; MUD, limited: 0%, extensive: 0%. All immunosuppressive-compliant patients successfully weaned immunosuppression. Although in limited patients, our results suggest that immunomodulatory TLI added to backbone CTX/ATG conditioning is a promising option for MUD HCT in SAA patients, which we will examine in a prospective clinical trial.

Alemtuzumab with fludarabine and cyclophosphamide reduces chronic graft-versus-host disease after allogeneic stem cell transplantation for acquired aplastic anemia

We evaluated a novel alemtuzumab-based conditioning regimen in HSCT for acquired severe aplastic anemia (SAA). In a multicenter retrospective study, 50 patients received transplants from matched sibling donors (MSD; n = 21) and unrelated donors (UD; n = 29), using fludarabine 30 mg/m2 for 4 days, cyclophosphamide 300 mg/m2 for 4 days, and alemtuzumab median total dose of 60 mg (range:40-100 mg). Median age was 35 years (range 8-62). Overall survival at 2 years was 95% ± 5% for MSD and 83% for UD HSCT (p 0.34). Cumulative incidence of graft failure was 9.5% for MSD and 14.5% for UD HSCT. Full-donor chimerism (FDC) in unfractionated peripheral blood was 42%; no patient achieved CD3 FDC. Acute GVHD was observed in only 13.5% patients (all grade I-II) and only 2 patients (4%) developed chronic GVHD. A low incidence of viral infections was seen. Factors influencing overall survival were HSCT comorbidity 2-year index (92% with score 0-1 vs 42% with score ≥ 2, P < .001) and age (92% for age < 50 years vs 71% ≥ 50 years, P < .001). Our data suggest that the use of an alemtuzumab-based HSCT regimen for SAA results in durable engraftment with a low incidence of chronic GVHD.

Clinical course of patients with aplastic anemia or myelodysplastic syndrome associated with persistent neutropenia

Patients with aplastic anemia (AA) or myelodysplastic syndrome (MDS) often have persistent severe neutropenia and are susceptible to infectious complications. We retrospectively reviewed the clinical course of patients with AA or MDS who had neutropenia (neutrophil count < 500/µl) for more than 25 days. A total of 46 patients, 11 with AA and 35 with MDS, were included. Twenty-three patients had infectious events (IE), and the cumulative incidence of IE was 30% at 6 months and 51% at 1 year. The cumulative incidence of IE was 67% at 1 year in 30 patients who experienced very severe neutropenia of less than 200/µl. Overall survival in all patients was 76% at 6 months and 65% at 1 year. In a multivariate analysis, male sex, underlying diseases, and a neutrophil count of less than 200/µl as a time-dependent covariate significantly affected IE. In analyses that excluded patients with AA, male sex was the only factor. In conclusion, severe neutropenia was significantly associated with IE in patients with AA or MDS, and IE might be lethal. When we only considered patients with MDS, the neutrophil count alone could not be used to predict the prognosis.

High-dose cyclophosphamide without stem cell rescue in 207 patients with aplastic anemia and other autoimmune diseases

High-dose cyclophosphamide has long been used as an anticancer agent, a conditioning regimen for hematopoietic stem cell transplantation, and a potent immunosuppressive agent in autoimmune diseases including aplastic anemia. High-dose cyclophosphamide is highly toxic to lymphocytes but spares hematopoietic stem cells because of their abundant levels of aldehyde dehydrogenase, the major mechanism of cyclophosphamide inactivation. High-dose cyclophosphamide therapy induces durable remissions in most patients with acquired aplastic anemia. Moreover, high-dose cyclophosphamide without hematopoietic stem cell rescue has shown activity in a variety of other severe autoimmune diseases. Here we review the history of cyclophosphamide as it applies to aplastic anemia and other autoimmune diseases. We include historical data from early patients treated for aplastic anemia as well as data from 140 patients from an observational retrospective study in a single tertiary care hospital. This latter component was designed to assess the safety and efficacy of high-dose cyclophosphamide therapy without stem cell rescue in patients with refractory autoimmune diseases. We analyzed the 140 patients with severe, progressive autoimmune diseases treated. All patients discussed here received cyclophosphamide, 50 mg/kg per day for 4 consecutive days. Response, relapse, and overall survival were measured. Response was defined as a decrease in disease activity in conjunction with a decrease or elimination of immune-modulating drugs. Relapse was defined as worsening disease activity and/or a requirement for an increase in dose of, or administration of new, immunosuppressive medications. Hematologic recovery occurred in all patients. The overall response rate was 94%, and 44% of those patients remained progression free with a median follow-up of 36 months (range, 1-120 mo) for the 140 patients analyzed together. The overall actuarial and event-free survival across all diseases at 60 months was 90.7% and 20.6%, respectively. High-dose cyclophosphamide without stem cell rescue is well tolerated and induces a high rate of remission in severe autoimmune diseases.

Immunohematopoietic stem cell transplantation in Cape Town: a ten-year outcome analysis in adults

BACKGROUND AND OBJECTIVES

Immunohematopoietic stem cell transplantation has curative potential in selected hematologic disorders. Stem cell transplantation was introduced into South Africa in 1970 as a structured experimental and clinical program. In this report, we summarize the demography and outcome by disease category, gender, and type of procedure in patients older than 18 years of age who were seen from April 1995 to December 2002.

PATIENTS AND METHODS

This retrospective analysis included 247 individuals over 18 years of age for whom complete data were available. These patients received grafts mostly from peripheral blood with the appropriate stem cell population recovered by apheresis.

RESULTS

Patient ages ranged from 20 to 65 years with a median age of 42 years. There were 101 females and 146 males. There were no withdrawals and 63% survived to the end of the study. At 96 months of follow-up, a stable plateau was reached for each disease category. Median survival was 3.3 years (n=6, 14.6%) for acute lymphoblastic anemia, 3.1 years (n=44, 18%) for acute myeloid leukemia, 2.8 years (n=47, 19%) for chronic granulocytic leukemia, 2.8 years (n=71, 29%) for lymphoma, 1.5 years (n=23, 9%) for myeloma, 1.43 years (n=10, 4%) for aplasia, and 1.4 years (n=38, 15%) for a miscellaneous group comprising less than 10 examples each. Multivariate analysis showed that only diagnosis and age had a significant impact on survival, but these two variables might be interrelated. There was no significant difference in outcome by source of graft.

CONCLUSION

The results confirm that procedures carried out in a properly constituted and dedicated unit, which meets established criteria and strictly observes treatment protocols, generate results comparable to those in a First World referral center. Low rates of transplant-related mortality, rejection and graft-versus-host disease are confirmed, but the benefits cannot be extrapolated outside of academically oriented and supervised facilities.

Is it time for a change? The case for early application of unrelated allo-SCT for severe aplastic anemia

Severe aplastic anemia (SAA) is a BM failure syndrome in which allo-SCT remains a highly effective curative option. Its application remains limited by donor availability and by the potential for treatment-related morbidity and mortality. The improved outcomes with unrelated transplantation are a result of the advent of molecular donor-recipient matching, generation of effective novel conditioning regimens, improvement of supportive care and expansion of the donor registry. Decision making regarding the earlier use of unrelated transplant procedures is rapidly evolving. This paper reviews critical data relevant to these treatment options and recommends early consideration of related SCT for patients with SAA who show failure of immune suppressive therapy.

Outcome of allogeneic hematopoietic cell transplantation from HLA-identical siblings for severe aplastic anemia in patients over 40 years of age

Patients with severe aplastic anemia (SAA) over 40 years of age are often not offered treatment with hematopoietic cell transplantation (HCT) because of concerns about treatment-related morbidity or mortality. To evaluate this risk, we analyzed outcomes after allogeneic HCT from HLA-identical sibling donors for all older patients with SAA at our center since 1988. The 23 consecutive patients ranged in age from 40 to 68 years. The conditioning regimen was cyclophosphamide (200 mg/kg) and horse antithymocyte globulin. Methotrexate and cyclosporine were given for postgrafting immunosuppression. The cumulative incidences of grades II, III, and IV acute graft-versus-host-disease were 30%, 4%, and 0%, respectively; that for chronic GVHD was 26%. With a median follow-up of 9.1 years, overall survival was 65%. Documented infections within 1 month before HCT were significantly associated with risk of early treatment-related mortality (P < .001). The median time to discontinuation of posttransplant immunosuppression was 6.2 (range: 5.9-92.0) months. Three patients developed superficial basal cell carcinoma between 5.5 and 15 years after HCT. Our data favor a practice of extending HLA-identical sibling HCT for treatment of SAA in patients older than 40 years of age who are without significant medical comorbidities.

Outcomes of matched sibling and alternative donor stem cell transplantation for 26 children with severe aplastic anemia

In this study, we reported the outcomes of hematopoietic stem cell transplantation (HSCT) as a treatment modality for pediatric patients admitted over the past 20 years in a single institute. From January 1989 to January 2007, 26 patients with a median age of 8 years underwent 14 matched sibling donor (MSD) and 12 alternative donor (AD) transplantations. Two patients received second transplantation successfully after primary graft failure and late graft rejection. Two patients who received transplantation from matched unrelated donors (MUD) died of sepsis, and one of them also had a graft failure at death. The overall 5-year survival rate was 92.1%: 83.3% for AD transplantation and 100% for MSD transplantation. Grade II acute graft versus host disease (GVHD) developed in 3 patients, and extensive chronic GVHD developed in 2 patients. An interval of more than 6 months from diagnosis to transplantation was the major poor prognostic factor for our patients' survival. Thus, in our experience, HSCT from a MSD remains the first choice of treatment for pediatric patients with severe aplastic anemia. For patients without MSD, transplantation from an AD can also result in long-term survival. Earlier transplantation after diagnosis can also result in better outcomes.

A retrospective comparison of cyclophosphamide plus antithymocyte globulin with cyclophosphamide plus busulfan as the conditioning regimen for severe aplastic anemia

Allogeneic hematopoietic stem cell transplantation (AHSCT) is the treatment of choice for young patients with severe aplastic anemia (SAA). The association of antithymocyte globulin (ATG) and cyclophosphamide (CY) is the most frequently used conditioning regimen for this disease. We performed this retrospective study in order to compare the outcomes of HLA-matched sibling donor AHSCT in 41 patients with SAA receiving cyclophosphamide plus ATG (ATG-CY, N = 17) or cyclophosphamide plus busulfan (BU-CY, N = 24). The substitution of BU for ATG was motivated by the high cost of ATG. There were no differences in the clinical features between the two groups, including age, gender, cytomegalovirus status, ABO match, interval between diagnosis and transplant, and number of total nucleated cells infused. No differences were observed in the time to neutrophil and platelet engraftment, or in the risk of veno-occlusive disease and hemorrhage. However, there was a higher risk of mucositis in the BU-CY group (71 vs 24%, P = 0.004). There were no differences in the incidence of neutrophil and platelet engraftment, acute and chronic graft-versus-host disease, and transplant-related mortality. There was a higher incidence of late rejection in the ATG-CY group (41 vs 4%, P = 0.009). Although the ATG-CY group had a longer follow-up (101 months) than the BU-CY group (67 months, P = 0.04), overall survival was similar between the groups (69 vs 58%, respectively, P = 0.32). We conclude that the association BU-CY is a feasible option to the conventional ATG-CY regimen in this population.

Allogeneic hematopoietic stem cell transplantation for acquired aplastic anemia using cyclophosphamide and antithymocyte globulin: a single center experience

Between February 1998 and October 2007, 97 (69 male, 28 female) patients with acquired aplastic anemia and a median age of 18 years (range, 2-39) received related allogeneic hematopoietic stem cell transplantation. Ninety-five patients received bone marrow grafts and two patients G-CSF primed peripheral blood stem cell transplantation. The donors were genotypically HLA-identical siblings in 94 cases, HLA-matched parents in 2 cases and a syngeneic twin in 1 case. Median time from diagnosis to transplantation was 2 months (range, 1-15). Conditioning regimen consisted of cyclophosphamide combined with antithymocyte globulin in all patients. For graft versus host disease (GVHD) prophylaxis, all patients received methotrexate and cyclosporine. Eighty-six patients showed evidence of hematopoietic engraftment. Eight patients died before engraftment. Rejection rate was 14.8% with three primary graft failures and eight secondary graft rejections occurring between 2 and 27 months post transplantation. Of the 11 rejecting patients, 3 died from infection and 8 proceeded to a second transplantation. Among the eight patients re-transplanted, seven are alive with successful second engraftments and one died from acute grade III GVHD. Acute GVHD occurred in 15.5% and extensive chronic GVHD in only 5.3% of patients. The 4-year overall probability of survival was 76.8%. Infection was the cause of 81.1% of deaths. The major factor affecting survival was onset of infection before transplantation. Major ABO donor-recipient incompatibility, disease severity and acute GVHD had also negative impact on survival. These results could be improved by reducing the time to transplant and by a more efficient supportive care policy.Bone Marrow Transplantation advance online publication, 27 July 2009; doi:10.1038/bmt.2009.175.

Hematopoietic stem cell transplantation for bone marrow failure syndromes in children

Bone marrow failure (BMF) syndromes include a broad group of diseases of varying etiologies, in which hematopoeisis is abnormal or completely arrested in one or more cell lines. BMF can be an acquired aplastic anemia (AA) or can be congenital, as part of such syndromes as Fanconi anemia (FA), Diamond Blackfan anemia, and Schwachman Diamond syndrome (SDS). In this review, we first address the evolution and current status of bone marrow transplantation (BMT) in the pediatric population in the most common form of BMF, acquired AA. We then discuss pediatric BMT in some of the more common inherited BMF syndromes, with emphasis on FA, in which experience is greatest. It is important to consider the possibility of a congenital etiology in every child (and adult) with marrow failure, because identification of an associated syndrome provides insight into the likely natural history of the disease, as well as prognosis, treatment options for the patient and family, and long-term sequelae both of the disease itself and its treatment.

Graft failure after allogeneic hematopoietic cell transplantation

Graft failure is a significant complication following allogeneic hematopoietic cell transplantation (alloHCT). It may result from rejection caused by recipient T cells, natural killer (NK) cells, or antibodies. It is increased in HLA-mismatched grafts, unrelated grafts, T cell-replete transplants, sensitized patients, and in patients treated with reduced-intensity conditioning (RIC). In recipients of unrelated grafts, graft failure is increased in patients receiving major AB0 blood group mismatched transplants (P = .008). Recent data also suggest that donor-specific antibodies to CD34(+)/VEGFR-2(+) cells may be involved in graft failure after alloHCT. Graft failure may be overcome by more intensified conditioning, increased cell dose, or more effective immunosuppression. With more frequent use of RIC, cord blood grafts and other HLA-mismatched transplants, graft failure is an increasing problem after alloHCT.

Allogeneic stem cell transplantation for severe aplastic anemia: graft rejection remains a problem

We reviewed the outcome in 15 consecutive patients with severe aplastic anemia with a median age of 23 years who received matched sibling peripheral blood stem cell transplantation. Conditioning regimen was cyclophosphamide (Cy)+anti-thymocyte globulin (ATG). Cumulative incidence of transplant related mortality, graft failure, acute and chronic GVHD were 20%, 33%, 25%, and 8.3%, respectively. Conditioning with Cy only, resulted in higher rejection rate compared to Cy plus ATG (75% versus 12.5%, p=0.03). Eighty percent of patients are alive with a median follow-up of 19.5 (4.6-35.6) months. Two of the three patients who were re-transplanted with fludarabine had sustained donor chimerism.

Reduced-intensity conditioning for severe aplasia using fludarabine and CY followed by infusion of ex vivo T-cell-depleted grafts leads to excellent engraftment and absence of GVHD

We studied the outcome of individuals with aplastic anaemia (AA) who received reduced-intensity conditioning followed by the infusion of stem cell grafts that had been T-cell depleted ex vivo with alemtuzumab. Consecutive patients with AA who had an HLA-identical sibling received conditioning with fludarabine 30 mg/m(2) daily for 5 days followed by CY 60 mg/kg on 2 consecutive days. Cytokine-mobilized blood grafts were incubated ex vivo with alemtuzumab 'in the bag' and infused without washing. CYA was prescribed until day +90. Engraftment rate, GVHD, EFS and overall survival were studied. Fifteen patients received PBPC grafts. It was the second graft in one of the patients. Ten patients were male and their median age was 23.5 years. The toxicity of the conditioning was minimal. One patient received 1 x 10(7)/kg donor lymphocytes for rising chimerism. At a median of 1107 (294-1778) days, all of them survived with normal blood parameters. None of them developed acute or chronic GVHD. In patients with AA the combination of purine analogue and alkylator leads to rapid engraftment despite T-cell depletion of grafts. This strategy of reduced-intensity conditioning has low toxicity, does not compromise engraftment and seems effective for prevention of GVHD.

Successful treatment of stem cell graft failure in pediatric patients using a submyeloablative regimen of campath-1H and fludarabine

Graft failure is a significant cause of morbidity and mortality after hematopoietic stem cell transplantation (HSCT). We used a nonmyeloablative conditioning regimen consisting of the lympho-depleting humanized CD52-antibody Campath-1H and fludarabine to rescue 12 consecutive children age 9 months to 17 years with engraftment failure after initial myeloablative HSCT. Primary diagnoses included lymphohematologic malignancies (n=6), severe combined immunodeficiency syndrome (SCID) (n=4), and metabolic diseases (n=2). The same stem cell donor was used as for the primary graft: mismatched family member (n=7), matched unrelated donor (n=4), or matched related donor (n=1). The patients received doses of CD34+ cells that did not significantly differ from those used in the initial, failed transplant. At a median follow-up of 51 months (range, 4 to 84 months), 6 of 6 patients with nonmalignant diseases and 4 of 6 patients with malignancy were alive. Two patients died, 1 patient from pulmonary toxicity and 1 from relapse, at 51 days and 8 months posttransplantation, respectively. All 12 patients initially achieved sustained neutrophil engraftment and complete donor chimerism by day 28. Six patients received donor lymphocyte infusion (DLI) after "rescue" therapy to maintain donor chimerism. At 6 months, 4 patients had complete donor cell engraftment, 4 had 15% to 89% stable donor chimerism, and 3 had developed secondary graft failure. This conditioning regimen was generally well tolerated; 4 of the 12 patients never became neutropenic, and 9 never became thrombocytopenic. Only 1 patient developed graft-versus-host disease (GVHD; grade 1), and none had chronic GVHD. Thus, the regimen that we describe can be used with minimal toxicity to effectively overcome graft failure after myeloablative HSCT in children.

A review of transfusion practice before, during, and after hematopoietic progenitor cell transplantation

The increased use of hematopoietic progenitor cell (HPC) transplantation has implications and consequences for transfusion services: not only in hospitals where HPC transplantations are performed, but also in hospitals that do not perform HPC transplantations but manage patients before or after transplantation. Candidates for HPC transplantation have specific and specialized transfusion requirements before, during, and after transplantation that are necessary to avert the adverse consequences of alloimmunization to human leukocyte antigens, immunohematologic consequences of ABO-mismatched transplantations, or immunosuppression. Decisions concerning blood transfusions during any of these times may compromise the outcome of an otherwise successful transplantation. Years after an HPC transplantation, and even during clinical remission, recipients may continue to be immunosuppressed and may have critically important, special transfusion requirements. Without a thorough understanding of these special requirements, provision of compatible blood components may be delayed and often urgent transfusion needs prohibit appropriate consultation with the patient's transplantation specialist. To optimize the relevance of issues and communication between clinical hematologists, transplantation physicians, and transfusion medicine physicians, the data and opinions presented in this review are organized by sequence of patient presentation, namely, before, during, and after transplantation.

Graft-versus-host disease following marrow transplantation for aplastic anemia: different impact of two GVHD prevention strategies

Prevention of GVHD is one of the most desirable goals of BMT in aplastic anemia (AA). We reviewed the medical records of 24 consecutive patients treated with BMT for acquired AA using two different GVHD prevention strategies. Ten patients were given alemtuzumab-based GVHD prophylaxis (50-60 mg in three divided doses on days -8, -7 and -6), and 14 patients were given conventional GVHD prophylaxis with calcineurin inhibitors plus MTX before the introduction of the alemtuzumab-based protocols. The incidence of acute, chronic and 'serious GVHD' was significantly reduced in alemtuzumab-treated patients compared to conventionally treated patients [11 vs 64% (P=0.03), 0 vs 78% (P=0.002) and 0 vs 57% (P=0.007), respectively]. Engraftment time and rates of graft failure appeared similar in the two groups. A significantly higher proportion of alemtuzumab-treated patients developed CMV reactivation compared to control patients (83 vs 12%; P=0.03); none developed CMV disease. The rates of other infectious complications did not appear significantly different. Our data suggest that 50-60 mg of alemtuzumab given according to the current schedule significantly reduces the risk of GVHD without increasing the risk of graft failure or serious infections.