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We developed a risk score to predict event-free survival (EFS) after allogeneic hematopoietic cell transplantation for sickle cell disease. The study population (n = 1425) was randomly split into training (n = 1070) and validation (n = 355) cohorts. Risk factors were identified and validated via Cox regression models. Two risk factors of 9 evaluated were predictive for EFS: age at transplantation and donor type. On the basis of the training cohort, patients age 12 years or younger with an HLA-matched sibling donor were at the lowest risk with a 3-year EFS of 92% (score, 0). Patients age 13 years or older with an HLA-matched sibling donor or age 12 years or younger with an HLA-matched unrelated donor were at intermediate risk (3-year EFS, 87%; score, 1). All other groups, including patients of any age with a haploidentical relative or HLA-mismatched unrelated donor and patients age 13 years or older with an HLA-matched unrelated donor were high risk (3-year EFS, 57%; score, 2 or 3). These findings were confirmed in the validation cohort. This simple risk score may guide patients with sickle cell disease and hematologists who are considering allogeneic transplantation as a curative treatment relative to other available contemporary treatments.

Outcomes remain poor for refractory severe aplastic anemia (SAA) patients. Alternative donor transplantation may be considered, but results from previous studies are not encouraging. We conducted a prospective nationwide phase 2 study to assess unrelated cord blood (CB) transplantation (CBT) efficacy and safety in refractory SAA patients (Aplastic Anemia and Cord Blood Transplantation protocol). To demonstrate a significant difference in 1-year survival from 20% (null hypothesis) to 50% (alternative hypothesis), we needed to include 25 transplanted patients and therefore included 26 (median age, 16 years). Eligibility criteria required 1 or 2 unrelated CB units, containing separately or together >4 × 10 7 frozen nucleated cells (NCs) per kilogram of recipient body weight. Conditioning regimen comprised fludarabine (FLU), cyclophosphamide (CY), antithymocyte globulin (ATG), and 2-Gy total body irradiation (TBI). With a median follow-up of 38.8 months, engraftment occurred in 23 patients (88%); cumulative incidences of grade II-IV acute and chronic graft-versus-host disease were 45.8% and 36%, respectively. Twenty-three patients were alive at 1 year, with an 88.5% overall survival (OS) rate, differing significantly from the expected 20% ( P < .0001; 84% OS at 2 years). CBT with units containing ≥4 × 10 7 frozen NCs per kilogram is therefore a valuable curative option for young adults with refractory SAA and no available matched unrelated donors. This trial was registered at www.clinicaltrials.gov as #NCT01343953., (© 2018 by The American Society of Hematology.)

Despite advances in supportive therapy to prevent complications of sickle cell disease (SCD), access to care is not universal. Hematopoietic cell transplantation is, to date, the only curative therapy for SCD, but its application is limited by availability of a suitable HLA-matched donor and lack of awareness of the benefits of transplant. Included in this study are 1000 recipients of HLA-identical sibling transplants performed between 1986 and 2013 and reported to the European Society for Blood and Marrow Transplantation, Eurocord, and the Center for International Blood and Marrow Transplant Research. The primary endpoint was event-free survival, defined as being alive without graft failure; risk factors were studied using a Cox regression models. The median age at transplantation was 9 years, and the median follow-up was longer than 5 years. Most patients received a myeloablative conditioning regimen (n = 873; 87%); the remainder received reduced-intensity conditioning regimens (n = 125; 13%). Bone marrow was the predominant stem cell source (n = 839; 84%); peripheral blood and cord blood progenitors were used in 73 (7%) and 88 (9%) patients, respectively. The 5-year event-free survival and overall survival were 91.4% (95% confidence interval, 89.6%-93.3%) and 92.9% (95% confidence interval, 91.1%-94.6%), respectively. Event-free survival was lower with increasing age at transplantation (hazard ratio [HR], 1.09; P < .001) and higher for transplantations performed after 2006 (HR, 0.95; P = .013). Twenty-three patients experienced graft failure, and 70 patients (7%) died, with the most common cause of death being infection. The excellent outcome of a cohort transplanted over the course of 3 decades confirms the role of HLA-identical sibling transplantation for children and adults with SCD., (© 2017 by The American Society of Hematology.)

We evaluated the impact of recipient and cord blood unit (CBU) genetic polymorphisms related to immune response on outcomes after unrelated cord blood transplantations (CBTs). Pretransplant DNA samples from 696 CBUs with malignant diseases were genotyped for NLRP1, NLRP2, NLRP3, TIRAP/Mal, IL10, REL, TNFRSF1B, and CTLA4. HLA compatibility was 6 of 6 in 10%, 5 of 6 in 39%, and ≥4 of 6 in 51% of transplants. Myeloablative conditioning was used in 80%, and in vivo T-cell depletion in 81%, of cases. The median number of total nucleated cells infused was 3.4 × 10 7 /kg. In multivariable analysis, patients receiving CBUs with GG-CTLA4 genotype had poorer neutrophil recovery (hazard ratio [HR], 1.33; P = .02), increased nonrelapse mortality (NRM) (HR, 1.50; P < .01), and inferior disease-free survival (HR, 1.41; P = .02). We performed the same analysis in a more homogeneous subset of cohort 1 (cohort 2, n = 305) of patients who received transplants for acute leukemia, all given a myeloablative conditioning regimen, and with available allele HLA typing (HLA-A, -B, -C, and -DRB1). In this more homogeneous but smaller cohort, we were able to demonstrate that GG-CTLA4-CBU was associated with increased NRM (HR, 1.85; P = .01). Use of GG-CTLA4-CBU was associated with higher mortality after CBT, which may be a useful criterion for CBU selection, when multiple CBUs are available., (© 2017 by The American Society of Hematology.)

Stroke risk in sickle cell anemia (SCA), predicted by high transcranial Doppler (TCD) velocities, is prevented by transfusions. We present the long-term follow-up of SCA children from the Créteil newborn cohort (1992-2012) detected at risk by TCD and placed on chronic transfusions. Patients with normalized velocities and no stenosis were treated with hydroxyurea, known to decrease anemia and hemolytic rate. Trimestrial Doppler was performed and transfusions restarted immediately in the case of reversion to abnormal velocities. Patients with a genoidentical donor underwent transplant. Abnormal time-averaged maximum mean velocities (TAMMV) ≥200 cm/s were detected in 92 SCA children at a mean age of 3.7 years (range, 1.3-8.3 years). No stroke occurred posttransfusion after a mean follow-up of 6.1 years. Normalization of velocities (TAMMV < 170 cm/s) was observed in 83.5% of patients. Stenosis, present in 27.5% of patients, was associated with the risk of non-normalization (P< .001). Switch from transfusions to hydroxyurea was prescribed for 45 patients, with a mean follow-up of 3.4 years. Reversion, predicted by baseline reticulocyte count ≥400 × 10(9)/L (P< .001), occurred in 28.9% (13/45) patients at the mean age of 7.1 years (range, 4.3-9.5 years). Transplant, performed in 24 patients, allowed transfusions to be safely stopped in all patients and velocities to be normalized in 4 patients who still had abnormal velocities on transfusions. This long-term cohort study shows that transfusions can be stopped not only in transplanted patients but also in a subset of patients switched to hydroxyurea, provided trimestrial Doppler follow-up and immediate restart of transfusions in the case of reversion., (© 2016 by The American Society of Hematology.)

We analyzed 661 adult patients who underwent single-unit (n = 226) or double-unit (n = 435) unrelated cord blood transplantation (UCBT) following a reduced-intensity conditioning (RIC) consisting of low-dose total body irradiation (TBI), cyclophosphamide, and fludarabine (Cy/Flu/TBI200). Eighty-two patients received rabbit antithymocyte globulin (ATG) as part of the conditioning regimen (ATG group), whereas 579 did not (non-ATG group). Median age at UCBT was 54 years, and diagnoses were acute leukemias (51%), myelodysplastic syndrome/myeloproliferative neoplasm (19%), and lymphoproliferative diseases (30%). Forty-four percent of patients were transplanted with advanced disease. All patients received ≥4 antigens HLA-matched UCBT. Median number of collected total nucleated cells was 4.4 × 10(7)/kg. In the ATG group, on 64 evaluable patients, ATG was discontinued 1 (n = 27), 2 (n = 20), or > 2 days before the graft infusion (n = 17). In multivariate analyses, the use of ATG was associated with decreased incidence of acute graft-versus-host disease (hazard ratio [HR], 0.31; 95% confidence interval [CI], 0.17-0.55; P < .0001), higher incidence of nonrelapse mortality (HR, 1.68; 95% CI, 1.16-2.43; P = .0009), and decreased overall survival (HR, 1.69; 95% CI, 1.19-2.415; P = .003). Collectively, our results suggest that the use of ATG could be detrimental, especially if given too close to graft infusion in adults undergoing UCBT following Cy/Flu/TBI200 regimen., (© 2015 by The American Society of Hematology.)

In this issue of Blood, MacMillan et al give the results of sequential modifications of the conditioning regimen to improve the outcome of unrelated bone marrow transplantation in Fanconi anemia (FA). Over a period of 10 years, they show that transplant toxicity has decreased and engraftment has improved, resulting in a 5-year overall survival probability of 94%. The major change was the use of fludarabine in the conditioning, with decreased doses of irradiation and cyclophosphamide. They attribute their success to progressive modifications of the conditioning regimen; nevertheless, the improvement may also have been due to better patient selection, use of high-resolution HLA typing for donor selection, and improved supportive care treatment.

We studied the effect of allele-level matching at human leukocyte antigen (HLA)-A, -B, -C, and -DRB1 in 1568 single umbilical cord blood (UCB) transplantations for hematologic malignancy. The primary end point was nonrelapse mortality (NRM). Only 7% of units were allele matched at HLA-A, -B, -C, and -DRB1; 15% were mismatched at 1, 26% at 2, 30% at 3, 16% at 4, and 5% at 5 alleles. In a subset, allele-level HLA match was assigned using imputation; concordance between HLA-match assignment and outcome correlation was confirmed between the actual and imputed HLA-match groups. Compared with HLA-matched units, neutrophil recovery was lower with mismatches at 3, 4, or 5, but not 1 or 2 alleles. NRM was higher with units mismatched at 1, 2, 3, 4, or 5 alleles compared with HLA-matched units. The observed effects are independent of cell dose and patient age. These data support allele-level HLA matching in the selection of single UCB units.

We retrospectively analyzed 110 patients with juvenile myelomonocytic leukemia, given single-unit, unrelated donor umbilical cord blood transplantation. Median age at diagnosis and at transplantation was 1.4 years (age range, 0.1-6.4 years) and 2.2 years (age range, 0.5-7.4 years), respectively. Before transplantation, 88 patients received chemotherapy; splenectomy was performed in 24 patients. Monosomy of chromosome 7 was the most frequent cytogenetic abnormality, found in 24% of patients. All but 8 patients received myeloablative conditioning; cyclosporine plus steroids was the most common graft-versus-host disease prophylaxis. Sixteen percent of units were HLA-matched with the recipient, whereas 43% and 35% had either 1 or 2 to 3 HLA disparities, respectively. The median number of nucleated cells infused was 7.1 × 10(7)/kg (range, 1.7-27.6 × 10(7)/kg). With a median follow-up of 64 months (range, 14-174 months), the 5-year cumulative incidences of transplantation-related mortality and relapse were 22% and 33%, respectively. The 5-year disease-free survival rate was 44%. In multivariate analysis, factors predicting better disease-free survival were age younger than 1.4 years at diagnosis (hazard ratio [HR], 0.42; P = .005), 0 to 1 HLA disparities in the donor/recipient pair (HR, 0.4; P = .009), and karyotype other than monosomy 7 (HR, 0.5; P = .02). Umbilical cord blood transplantation may cure a relevant proportion of children with juvenile myelomonocytic leukemia. Because disease recurrence remains the major cause of treatment failure, strategies to reduce incidence of relapse are warranted.

We analyzed the outcomes of 485 patients with thalassemia major (TM) or sickle cell disease (SCD) receiving HLA-identical sibling cord blood transplantation (CBT, n = 96) or bone marrow transplantation (BMT, n = 389). Compared with patients given BMT, CBT recipients were significantly younger (median age 6 vs 8 years, P = .02), and were treated more recently (median year 2001 vs 1999, P < .01). A higher proportion of patients with TM belonging to classes II-III of the Pesaro classification received BMT (44%) compared with CBT (39%, P < .01). In comparison with patients receiving BMT (n = 259, TM; n = 130, SCD), those given CBT (n = 66, TM; n = 30, SCD) had slower neutrophil recovery, less acute graft-versus-host disease (GVHD) and none had extensive chronic GVHD. With a median follow-up of 70 months, the 6-year overall survival was 95% and 97% after BMT and CBT, respectively (P = .92). The 6-year disease-free survival (DFS) was 86% and 80% in TM patients after BMT and CBT, respectively, whereas DFS in SCD patients was 92% and 90%, respectively. The cell dose infused did not influence outcome of patients given CBT. In multivariate analysis, DFS did not differ between CBT and BMT recipients. Patients with TM or SCD have excellent outcomes after both HLA-identical sibling CBT and BMT.

Umbilical cord blood is an alternative hematopoietic stem cell source for patients with hematologic diseases who can be cured by allogeneic hematopoietic cell transplantation. Initially, umbilical cord blood transplantation was limited to children, given the low cell dose infused. Both related and unrelated cord blood transplants have been performed with high rates of success for a variety of hematologic disorders and metabolic storage diseases in the pediatric setting. The results for adult umbilical cord blood transplantation have improved, with greater emphasis on cord blood units of sufficient cell dose and human leukocyte antigen match and with the use of double umbilical cord blood units and improved supportive care techniques. Cord blood expansion trials have recently shown improvement in time to engraftment. Umbilical cord blood is being compared with other graft sources in both retrospective and prospective trials. The growth of the field over the last 25 years and the plans for future exploration are discussed.

We report transplantation outcomes of 258 children with Hurler syndrome (HS) after a myeloablative conditioning regimen from 1995 to 2007. Median age at transplant was 16.7 months and median follow-up was 57 months. The cumulative incidence of neutrophil recovery at day 60 was 91%, acute graft-versus-host disease (GVHD) (grade II-IV) at day 100 was 25%, and chronic GVHD and 5 years was 16%. Overall survival and event-free survival (EFS) at 5 years were 74% and 63%, respectively. EFS after HLA-matched sibling donor (MSD) and 6/6 matched unrelated cord blood (CB) donor were similar at 81%, 66% after 10/10 HLA-matched unrelated donor (UD), and 68% after 5/6 matched CB donor. EFS was lower after transplantation in 4/6 matched unrelated CB (UCB) (57%; P = .031) and HLA-mismatched UD (41%; P = .007). Full-donor chimerism (P = .039) and normal enzyme levels (P = .007) were higher after CB transplantation (92% and 98%, respectively) compared with the other grafts sources (69% and 59%, respectively). In conclusion, results of allogeneic transplantation for HS are encouraging, with similar EFS rates after MSD, 6/6 matched UCB, 5/6 UCB, and 10/10 matched UD. The use of mismatched UD and 4/6 matched UCB was associated with lower EFS.

To describe the incidence, risk factors, and treatment of autoimmune diseases (ADs) occurring after cord blood transplantation (CBT), we analyzed both CBT recipients reported to EUROCORD who had developed at least 1 new AD and those who had not. Fifty-two of 726 reported patients developed at least 1 AD within 212 days (range, 27-4267) after CBT. Cumulative incidence of ADs after CBT was 5.0% +/- 1% at 1 year and 6.6% +/- 1% at 5 years. Patients developing ADs were younger and had more nonmalignant diseases (P < .001). ADs target hematopoietic (autoimmune hemolytic anemia, n = 20; Evans syndrome, n = 9; autoimmune thrombocytopenia, n = 11; and immune neutropenia, n = 1) and other tissues (thyroiditis, n = 3; psoriasis, n = 2; Graves disease, n 1; membranous glomerulonephritis, n = 2; rheumatoid arthritis, n = 1; ulcerative colitis, n = 1; and systemic lupus erythematosus, n = 1). Four patients developed 2 ADs (3 cases of immune thrombocytopenia followed by autoimmune hemolytic anemia and 1 Evans syndrome with rheumatoid arthritis). By multivariate analysis, the main risk factor for developing an AD was nonmalignant disease as an indication for CBT (P = .0001). Hematologic ADs were most often treated with steroids, rituximab, and cyclosporine. With a median follow-up of 26 months (range, 2-91), 6 of 52 patients died as a consequence of ADs. We conclude that CBT may be followed by potentially life-threatening, mainly hematologic ADs.

Pediatric patients with SCID constitute medical emergencies. In the absence of an HLA-identical hematopoietic stem cell (HSC) donor, mismatched related-donor transplantation (MMRDT) or unrelated-donor umbilical cord blood transplantation (UCBT) are valuable treatment options. To help transplantation centers choose the best treatment option, we retrospectively compared outcomes after 175 MMRDTs and 74 UCBTs in patients with SCID or Omenn syndrome. Median follow-up time was 83 months and 58 months for UCBT and MMRDT, respectively. Most UCB recipients received a myeloablative conditioning regimen; most MMRDT recipients did not. UCB recipients presented a higher frequency of complete donor chimerism (P = .04) and faster total lymphocyte count recovery (P = .04) without any statistically significance with the preparative regimen they received. The MMRDT and UCBT groups did not differ in terms of T-cell engraftment, CD4(+) and CD3(+) cell recoveries, while Ig replacement therapy was discontinued sooner after UCBT (adjusted P = .02). There was a trend toward a greater incidence of grades II-IV acute GVHD (P = .06) and more chronic GVHD (P = .03) after UCBT. The estimated 5-year overall survival rates were 62% ± 4% after MMRDT and 57% ± 6% after UCBT. For children with SCID and no HLA-identical sibling donor, both UCBT and MMRDT represent available HSC sources for transplantation with quite similar outcomes.

To specify the incidence and risk factors for secondary autoimmune diseases (ADs) after HSCT for a primary AD, we retrospectively analyzed AD patients treated by HSCT reported to EBMT from 1995 to 2009 with at least 1 secondary AD (cases) and those without (controls). After autologous HSCT, 29 of 347 patients developed at least 1 secondary AD within 21.9 (0.6-49) months and after allogeneic HSCT, 3 of 16 patients. The observed secondary ADs included: autoimmune hemolytic anemia (n = 3), acquired hemophilia (n = 3), autoimmune thrombocytopenia (n = 3), antiphospholipid syndrome (n = 2), thyroiditis (n = 12), blocking thyroid-stimulating hormone receptor antibody (n = 1), Graves disease (n = 2), myasthenia gravis (n = 1), rheumatoid arthritis (n = 2), sarcoidosis (n = 2), vasculitis (n = 1), psoriasis (n = 1), and psoriatic arthritis (n = 1). After autologous HSCT for primary AD, the cumulative incidence of secondary AD was 9.8% ± 2% at 5 years. Lupus erythematosus as primary AD, and antithymocyte globulin use plus CD34(+) graft selection were important risk factors for secondary AD by multivariate analysis. With a median follow-up of 6.2 (0.54-11) years after autologous HSCT, 26 of 29 patients with secondary AD were alive, 2 died during their secondary AD (antiphospholipid syndrome, hemophilia), and 1 death was HSCT-related. This European multicenter study underlines the need for careful management and follow-up for secondary AD after HSCT.

Fanconi anemia (FA) is a genetic condition associated with bone marrow (BM) failure, myelodysplasia (MDS), and acute myeloid leukemia (AML). We studied 57 FA patients with hypoplastic or aplastic anemia (n = 20), MDS (n = 18), AML (n = 11), or no BM abnormality (n = 8). BM samples were analyzed by karyotype, high-density DNA arrays with respect to paired fibroblasts, and by selected oncogene sequencing. A specific pattern of chromosomal abnormalities was found in MDS/AML, which included 1q+ (44.8%), 3q+ (41.4%), -7/7q (17.2%), and 11q- (13.8%). Moreover, cryptic RUNX1/AML1 lesions (translocations, deletions, or mutations) were observed for the first time in FA (20.7%). Rare mutations of NRAS, FLT3-ITD, MLL-PTD, ERG amplification, and ZFP36L2-PRDM16 translocation, but no TP53, TET2, CBL, NPM1, and CEBPα mutations were found. Frequent homozygosity regions were related not to somatic copy-neutral loss of heterozygosity but to consanguinity, suggesting that homologous recombination is not a common progression mechanism in FA. Importantly, the RUNX1 and other chromosomal/genomic lesions were found at the MDS/AML stages, except for 1q+, which was found at all stages. These data have implications for staging and therapeutic managing in FA patients, and also to analyze the mechanisms of clonal evolution and oncogenesis in a background of genomic instability and BM failure.

We analyzed risk factors influencing outcomes after related (R) human leukocyte antigen-identical cord blood transplantation (CBT) for 147 patients with malignancies reported to Eurocord-European Group for Blood and Marrow Transplantation. CBT has been performed since 1990; median follow-up was 6.7 years. Median patient age was 5 years. Acute leukemia was the most frequent diagnosis (74%). At CBT, 40 patients had early, 70 intermediate, and 37 advanced disease. CB grafts contained a median of 4.1 × 10(7)/kg total nucleated cells (TNCs) after thawing. The cumulative incidence (CI) of neutrophil recovery was 90% at day +60. CIs of acute and chronic graft-versus-host disease (GVHD) were 12% and 10% at 2 years, respectively. At 5 years, CIs of nonrelapse mortality and relapse were 9% and 47%, respectively; the probability of disease-free survival (DFS) and overall survival were 44% and 55%, respectively. Among other factors, higher TNCs infused was associated with rapid neutrophil recovery and improved DFS. The use of methotrexate as GVHD prophylaxis decreased the CI of engraftment. Patients without advanced disease had improved DFS. These results support banking and use of CB units for RCBT. Cell dose, GVHD prophylaxis not including methotrexate, and disease status are important factors for outcomes after RCBT.

The MHC class I-related chain A (MICA) molecules exist as membrane-bound and soluble isoforms and are encoded by a polymorphic gene. Their genetic and phenotype characteristics have been studied in various pathologic settings but not in the context of hematopoietic stem cell transplantation (HSCT). Here, we evaluated whether MICA-related features namely MICA-129 gene polymorphism, serum levels of soluble MICA (sMICA) and anti-MICA antibodies (MICA Abs) before and after HSCT could influence the incidence of chronic graft-versus-host disease (cGVHD) and relapse of their disease in 211 HLA-identical sibling pairs and in a subset of 116 recipients, respectively. Although the MICA-129 val/val genotype and elevated sMICA serum levels after HSCT are independently associated with the incidence of cGVHD (P = .002 and .001) regardless of history of acute GVHD, the presence of MICA Abs before transplantation confers protection against cGVHD (P = .04). There is an inverse relationship between MICA Abs and sMICA, suggesting an antibody-based neutralization of deleterious effects of sMICA. Similarly, these genetic and phenotype characteristics of MICA influence the incidence of relapse. Altogether, these data suggest that the studied MICA genotype and phenotype specificities could be used as relevant biomarkers for cGVHD monitoring.

In animal models, tissue stem cells were proposed to exhibit an unexpected level of plasticity, although issues on cell fusions have lead to some controversies. Only transplantation experiments using genetically distinct recipients and donors can unequivocally show these changes in cell fate. We have analyzed oral squamous cell carcinomas arising in 8 long-term survivors of allogeneic bone marrow transplantation, in whom chronic graft-versus-host disease greatly favors development of squamous cell carcinomas, possibly as a consequence of lichenoid mucosal inflammation. With the use of 2 independent methods, (1) combined immunostaining and fluorescent in situ hybridization (FISH) analysis for X and Y chromosomes sequences in sex-mismatched grafts and (2) comparison of microsatellite typing of laser-microdissected tumor, donor, and recipient cells, in all tumors, we showed that 4 of these 8 epithelial tumors actually arose from the engrafted allogeneic bone marrow. Thus, donor-derived bone marrow cells, whether hematopoietic or mesenchymal, recruited to sites of chronic mucosal inflammation yielded epithelial tumors. Our observations therefore show that marrow cells in humans have a major role in epithelial cancer formation after allogeneic transplantation.

Allogeneic hematopoietic stem-cell transplantation (HSCT) is the only curative treatment for sickle cell disease (SCD); nevertheless, its use has been limited by the risk of transplantation-related mortality (TRM). Between November 1988 and December 2004, 87 consecutive patients with severe SCD ranging from 2 to 22 years of age received transplants in France. Cerebral vasculopathy was the principal indication for transplantation (55 patients). All the patients received grafts from a sibling donor after a myeloablative conditioning regimen (CR). The only change in the CR during the study period was the introduction of antithymocyte globulin (ATG) in March 1992. The rejection rate was 22.6% before the use of ATG but 3% thereafter. With a median follow-up of 6 years (range, 2.0 to 17.9 years), the overall and event-free survival (EFS) rates were 93.1% and 86.1%, respectively. Graft versus host disease (GVHD) was the main cause of TRM. Importantly, cord blood transplant recipients did not develop GVHD. No new ischemic lesions were detected after engraftment, and cerebral velocities were significantly reduced. The outcome improved significantly with time: the EFS rate among the 44 patients receiving transplants after January 2000 was 95.3%. These results indicate that HLA-identical sibling HSCT after myeloablative conditioning with ATG should be considered as a standard of care for SCD children who are at high risk for stroke.

The addition of antithymocyte globulin (ATG) to a regimen of high-dose cyclophosphamide has been advocated to enhance engraftment after allogeneic bone marrow transplantation (BMT) for severe aplastic anemia (SAA). In a prospective clinical trial, 134 patients were randomly assigned to receive cyclophosphamide alone or in combination with ATG. All patients received T-cell-replete bone marrow from an HLA-matched sibling. With a median follow-up of 6 years, the 5-year probabilities of survival were 74% for the cyclophosphamide alone group and 80% for the cyclophosphamide plus ATG group (P = .44). Graft failure and graft-versus-host disease (GVHD) rates were similar in both groups. With the survival rates achieved, this study is not adequately powered to detect significant differences between the 2 treatment groups. In conclusion, the results of allogeneic BMT for SAA have improved over time related to advances in supportive care. The addition of ATG to the preparative regimen did not significantly improve the outcome.

Graft-versus-host disease (GvHD)-induced apoptosis of the skin targets both epidermal keratinocytes and dermal endothelial cells. We studied the donor-versus-recipient origin of GvHD of these target cells in skin of 18 sex-mismatched hematopoietic stem-cell transplant (HSCT) recipients. Combining XY fluorescence in situ hybridization (FISH) and double immunostaining, and further 3D tissue Z-stack analysis, we found keratinocytes and endothelial cells of donor origin, but only in patients with GvHD. Using terminal dUTP nick-end labeling (TUNEL) assay on sister sections, we found a correlation between the numbers of chimeric and apoptotic epidermal and endothelial cells. Moreover, donor-derived cells were more numerous and preferentially distributed in the areas of severe GvHD damage in biopsies performed early in the course of GvHD, whereas they were less numerous and found in the whole epidermis in late biopsies. Because donor-derived cells were found at the site and at the time of maximum tissue damage, they could contribute to epidermal and microvessel repair.

In the present study, we address the issue of the discontinuation of imatinib mesylate (Gleevec) in chronic myelogenous leukemia with undetectable residual disease for more than 2 years. Twelve patients were included. The median duration of real-time quantitative-polymerase chain reaction (RTQ-PCR) negativity and imatinib therapy were, respectively, 32 months (range, 24-46 months) and 45 months (range, 32-56 months) before imatinib interruption. Six patients displayed a molecular relapse with a detectable BCR-ABL transcript at 1, 1, 2, 3, 4, and 5 months. Imatinib was then reintroduced and led to a novel molecular response in most patients. Six other patients (50%) still have an undetectable level of BCR-ABL transcript after a median follow-up of 18 months (range, 9-24 months). We hypothesize that relapses observed within 6 months reflect the kinetics of undetectable dividing chronic myelogenous leukemia (CML) cells. Those cells may be eradicated or controlled in long-term nonrelapsing patients, as described in our study.

Thymic function is critical for immune reconstitution after hematopoietic stem cell transplantation (HSCT). We evaluated recipient thymic function before HSCT by quantifying T-cell receptor excision circles (TRECs) in pretransplantation peripheral blood lymphocytes from 102 patients who received HSCs from an HLA-identical sibling for malignant (n = 87) or nonmalignant diseases (n = 15). Median TREC value before transplantation was 257 TRECs per 150,000 CD3+ cells (range, 0-42,746). We assessed 172 TRECs per 150,000 CD3+ cells as the most discriminating TREC value for survival in a first cohort of patients (n = 62). This cut-off was validated in a second independent prospective group of 40 patients. In the 102 patients, a TREC value greater than or equal to 172 was associated with a better survival (P < .000 01), a decreased incidence of grade II-IV acute graft-versus-host disease (GVHD; P = .017), chronic GVHD (P = .023), and bacterial (P = .003) and cytomegalovirus (CMV) infection (P = .024). In a multivariate analysis, low pretransplantation TREC values were associated with a higher incidence of CMV infection (hazard ratio [HR] = 2.0, P = .06) and severe bacterial infections (HR = 2.8, P = .036). Finally, high TREC values (HR = 6.6, P = .002) and ABO compatibility (HR = 2.7, P = .02) were associated with a better survival. Therefore, recipient host thymic function assessment could be helpful in predicting HSCT outcome and identifying patients who require a close immunologic monitoring.

Fanconi anemia (FA) is characterized by congenital abnormalities, bone marrow failure, chromosome fragility, and cancer susceptibility. Eight FA-associated genes have been identified so far, the products of which function in the FA/BRCA pathway. A key event in the pathway is the monoubiquitination of the FANCD2 protein, which depends on a multiprotein FA core complex. In a number of patients, spontaneous genetic reversion can correct FA mutations, leading to somatic mosaicism. We analyzed the FA/BRCA pathway in 53 FA patients by FANCD2 immunoblots and chromosome breakage tests. Strikingly, FANCD2 monoubiquitination was detected in peripheral blood lymphocytes (PBLs) in 8 (15%) patients. FA reversion was further shown in these patients by comparison of primary fibro-blasts and PBLs. Reversion was associated with higher blood counts and clinical stability or improvement. Once constitutional FANCD2 patterns were determined, patients could be classified based on the level of FA/BRCA pathway disruption, as "FA core" (upstream inactivation; n = 47, 89%), FA-D2 (n = 4, 8%), and an unidentified downstream group (n = 2, 4%). FA-D2 and unidentified group patients were therefore relatively common, and they had more severe congenital phenotypes. These results show that specific analysis of the FA/BRCA pathway, combined with clinical and chromosome breakage data, allows a comprehensive characterization of FA patients.

Hematopoietic stem cell transplant (SCT) is currently the only therapy that can restore normal hematopoiesis in patients with Fanconi anemia (FA). Patients with FA have a high baseline risk of squamous cell cancers (SCCs) of the head, neck, and esophagus, and SCT conditioning may increase SCC incidence. We evaluated the risks of SCC and death in 145 patients with FA in the North American Survey (NAS) cohort who did not receive transplants, and 117 patients with FA in the Hôpital Saint Louis (SLH) cohort who did receive transplants. The age-specific hazard of SCC was 4.4-fold higher in patients who received transplants than in those who did not (P = .003), and SCCs occurred at significantly younger ages in the former (respective medians, 18 and 33 years, P = .004). Survival after SCC was similarly poor in both cohorts (P = .135, median, 13 months). The hazard of SCC increased at a greater than linear rate, to 4.4% per year by age 40 in NAS and 4.7% per year by 10 years after transplant in SLH. In SLH, the hazard of non-SCC death was biphasic, declining significantly (P = .004) from 7.1% per month during the first 6 months after transplant to 0.13% per month (1.6% per year) after the first year. Acute and chronic graft-versus-host diseases were significant SCC risk factors. Adverse event rates in these cohorts provide historical control rates to assess emerging therapies for FA.

In an experimental model we demonstrated that endothelial cells of all organs are targets of the alloimmune reaction. Here, in 68 digestive biopsies, we found endothelial lesions by immunohistochemistry and ultrastructure in patients with severe acute graft-versus-host disease (GVHD). In contrast, no such endothelial cell alterations were found either in patients without GVHD or in nongrafted controls. In the biopsies with severe GVHD lesions, ultrastructure showed rupture of the capillary basal membrane and extravased red blood cells. These pericapillary hemorrhages were highly correlated with GVHD severity. In a separate cohort of 39 patients who underwent an allogeneic transplantation after a nonmyeloablative conditioning, 8 patients had intestinal biopsies. Three of these latter patients had both severe pathologic lesions of GVHD and similar endothelial lesions, thus, strengthening the concept that endothelial lesions are linked to GVHD severity and not to the intensity of the conditioning regimen. (Blood. 2004;103:4681-4684)

From January 1978 to December 2001, 133 patients with severe aplastic anemia (SAA) underwent non-T cell-depleted allogeneic bone marrow transplantation from an HLA-identical sibling donor, at the Hospital Saint Louis using either the combination of cyclophosphamide (Cy) and thoracoabdominal irradiation (TAI; n=100) or Cy and antithymocyte globulin (ATG; n=33), as a conditioning regimen. With 13.6 years of follow-up, the 10-year survival estimate was 64%. Four factors were associated with lower survival: older age, use of Cy-TAI, any form of treatment prior to transplantation (either androgens or immunosuppressive therapy, [IST]), and grade II to IV acute graft-versus-host disease (GvHD). TAI was the sole factor associated with the occurrence of acute GvHD. The risk of cancers (15-year cumulative incidence, 10.9%) was associated with older age and with the use of cyclosporine as IST before transplantation. Cumulative incidences and risk factors of nonmalignant late effect including avascular osteonecrosis and late bacterial, viral, and fungal infection were also analyzed. Improved results using Cy-ATG as conditioning can lead to more than 90% chance of cure in patients with SAA. Even if, in our experience, the role of Cy-ATG versus that of Cy-TAI remained inextricably related to the year of transplantation, the major detrimental role of the GvHD disease in the long-term outcome and its relation to TAI supports avoidance of irradiation in the conditioning regimen. Furthermore, avoidance of any IST before transplantation in patients with a sibling donor is a prerequisite for attaining such excellent results.

Chronic hepatitis C is often asymptomatic, at least during the first decade following hematopoietic stem cell transplantation. Progression to advanced liver disease or cirrhosis in patients surviving more than 10 years is currently thought to be rare. Among 1078 patients who underwent an allogeneic transplantation between January 1973 and January 1995, 96 patients infected by hepatitis C virus (HCV) during the transplantation period were studied. Cumulative incidence and analysis of risk factors for cirrhosis were analyzed, and the rate and risk of cirrhosis in transplant recipients were compared with those of 158 HCV-infected controls who did not receive transplants. At a median follow-up of 15.7 years, 15 patients developed biopsy-proven cirrhosis, leading to a cumulative incidence of cirrhosis of 11% and 24% at 15 and 20 years, respectively. By multivariate analysis, extrahepatic HCV manifestations and HCV genotype 3 were associated with risk of cirrhosis. The median time to cirrhosis in transplant recipients was 18 years as compared with 40 years in the control population. The risk of cirrhosis in transplant recipients relative to controls was significantly higher by multivariate analysis (P =.0008). Roughly a quarter of long-term HCV-infected survivors with transplants progressed to cirrhosis that is much more rapid than in patients without transplants. Systematic detection of HCV infection, liver biopsy, and therapeutic intervention are therefore warranted in long-term marrow transplant recipients.

To assess whether Fanconi anemia (FA) patients might be at risk for acute graft-versus-host disease (AGvHD) despite using low-intensity conditionings, we retrospectively analyzed the incidence of AGvHD and its impact on outcome in 37 FA patients and 73 patients with acquired aplastic anemia (AAA) that received transplants at Saint Louis Hospital from HLA-genotypic identical siblings with similar conditionings (thoraco-abdominal irradiation plus cyclophosphamide 20 [FA] or 150 mg/kg [AAA]). Despite being younger, FA patients had an increased risk of grades II to IV AGvHD (relative risk [RR], 2.00; P =.021), especially in younger patients (RR, 7.93; P =.014). The risks of requiring systemic corticosteroids to treat AGvHD and experiencing cortico-resistant AGvHD were significantly increased in FA patients. Although non-FA and FA patients had similar 10-year outcomes, acute and chronic GvHD had a biphasic effect on FA patient outcome with an additional cluster of lethal events starting by 5 years after transplantation. This late survival fall, restricted to FA patients, was closely related to head and neck carcinomas (15-year incidence: 53%). FA patients represent a group at risk regarding AGvHD when using irradiation-based conditionings. The impact of AGvHD on survival may not be limited to the early posttransplantation period and may be a major risk factor for head and neck carcinomas and late mortality in FA patients.

Donor origin of epithelial intestinal cells has been studied in animals and humans after transplantation and has been used as evidence of hematopoietic stem cell (HSC) plasticity. However, in the human gastrointestinal tract, no study used X- or Y-chromosome detection by fluorescence in situ hybridization (FISH) coupled with immunologic stainings to characterize cell types on the same tissue section. Here, we combined these techniques on the same section of duodenal epithelium in 6 patients with acute graft-versus-host disease. Donor-derived lymphoid cells were detected in the epithelium and the lamina propria, as expected. However, using our stringent criteria, no donor-derived cells could be proven to be epithelial.