Solid organ transplantation after hematopoietic stem cell transplantation in childhood: A multicentric retrospective survey

We report data obtained from a retrospective multicenter pediatric survey on behalf of the European Society for Blood and Marrow Transplantation (EBMT). Information on solid organ transplantation (SOT) performed in pediatric recipients of either autologous or allogeneic hematopoietic stem cell transplantation (HSCT) between 1984 and 2016 was collected in 20 pediatric EBMT Centers (25.6%). Overall, we evaluated data on 44 SOTs following HSCT including 20 liver (LTx), 12 lung (LuTx), 6 heart (HTx), and 6 kidney (KTx) transplantations. The indication for SOT was organ failure related to intractable graft-vs-host disease in 16 children (36.3%), acute or chronic HSCT-related toxicity in 18 (40.9%), and organ dysfunction related to the underlying disease in 10 (22.8%). The median follow-up was 10.9 years (95% confidence interval: 1.7-29.5). The overall survival rate at 1 and 5 years after SOT was 85.7% and 80.4%, respectively: it was 74% and 63.2% after LTx, 83.2% after HTx, and 100% equally after LuTx and KTx. This multicenter survey confirms that SOT represents a promising option in children with severe organ failure occurring after HSCT. Additional studies are needed to further establish the effectiveness of SOT after HSCT and to better understand the mechanism underlying this encouraging success.

Cost-Effectiveness of Defibrotide in the Prophylaxis of Veno-Occlusive Disease after Pediatric Allogeneic Stem Cell Transplantation

Veno-occlusive disease (VOD) remains a serious complication after allogeneic hematopoietic stem cell transplantation (HSCT). Prophylactic use of defibrotide (DF) might further reduce VOD rates but has no impact on the incidence of severe VOD or VOD-associated mortality. We investigated the cost-effectiveness of prophylactic DF according to the British Committee for Standards in Haematology/British Society for Blood and Marrow Transplantation guidelines in 348 children who underwent transplantation between 2001 and 2014 in our hospital, 138 of whom were at risk for VOD. The VOD incidence was 7.4% for the total cohort. Patients at risk had a higher incidence of VOD compared with patients without risk factors (15.2% versus 2.4%, P < .0001). VOD occurred more often in patients after busulfan-based myeloablative conditioning than in patients after total body irradiation (11.2% versus 3.5%, P = .001). Donor types or the transplantation-related mortality (TRM) risk score did not correlate with VOD incidence. In 81% of patients who responded to therapeutic DF, VOD resolved completely. Overall VOD-associated mortality was .3% for the complete cohort, 3.7% for patients diagnosed with VOD, and 20% for patients with severe VOD. Neither the cumulative incidence of TRM (19% ± 8% versus 17% ± 2%, P = .706) nor the median length of hospitalization differed between patients with VOD and patients without. The median costs per HSCT in patients with VOD were about one-third higher than the overall median costs per transplantation at our institution. The calculated total costs of prophylactic DF treatment for 138 patients at risk was almost 6 times as high as the incremental costs for patients with VOD. We conclude that prophylactic DF for children at risk for VOD is not cost-effective with respect to TRM and length of hospital stay.

Sickle cell disease: an international survey of results of HLA-identical sibling hematopoietic stem cell transplantation

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.

Peripheral blood late mixed chimerism in leucocyte subpopulations following allogeneic stem cell transplantation for childhood malignancies: does it matter?

The impact of persistent mixed chimerism (MC) after haematopoietic stem cell transplantation (HSCT) remains unclarified. We investigated the incidence of MC in peripheral blood beyond day +50 after HSCT and its impact on rejection, chronic graft-versus-host disease (c-GvHD) and relapse in 161 children receiving allogeneic HSCT for haematological malignancies. The 1-year incidence of late MC was 26%. Spontaneous conversion to complete donor chimerism (CC) occurred in 43% of patients as compared to 62% after donor lymphocyte infusions. No graft rejection occurred. The 1-year incidence of c-GvHD was 20 ± 7% for MC, and 18 ± 4% for CC patients (P = 0·734). The 3-year cumulative incidence of relapse (CIR) according to chimerism status at days +50 and +100 was 22 ± 4% for CC patients vs. 22 ± 8% for MC patients (day +50; P = 0·935) and 21 ± 4% vs. 20 ± 7% (day +100; P = 0·907). Three-year CIRs in patients with persistent MC and patients with CC/limited MC were comparable (8 ± 7% vs. 19 ± 4%; P = 0·960). HSCT for acute leukaemia or myelodysplastic syndrome as secondary malignancies (hazard ratio (HR) 4·7; P = 0·008), for AML (HR 3·0; P = 0·02) and from mismatched donors (HR 3·1; P = 0·03) were independent factors associated with relapse. Our data suggest that late MC neither protects from c-GvHD nor does it reliably predict impending disease relapse.

Two pregnancies shortly after transplantation with reduced intensity conditioning in chronic myeloid leukemia

POI is a relevant late complication after HSCT and occurring more frequently after MAC than after RIC regimens. Reports on the frequency of POI after RIC in a large pediatric and adolescent population are lacking. In this study, we describe a girl affected by CML diagnosed at the age of 15 yr and treated with oncarbide and interferon followed by imatinib and dasatinib. She had two pregnancies shortly after RIC performed according to the CML-SCT I-BFM protocol including TT, FLU, and MEL. Hypergonadotropic hypogonadism occurred four months after HSCT; menstruations resumed regularly six months after HSCT. Eight and 20 months after HSCT, the patient became pregnant and then delivered, respectively, two babies at term by cesarean section. Both newborns had no neonatal complications. Donor chimerism at time of two pregnancies and five yr after transplantation demonstrated complete donor engraftment. These findings suggest that I-BFM CML-SCT protocol could be a promising treatment option for adolescents or young adults with CML eligible for HSCT.

The syndrome of hemophagocytic lymphohistiocytosis in primary immunodeficiencies: implications for differential diagnosis and pathogenesis

Hemophagocytic lymphohistiocytosis is a hyperinflammatory syndrome defined by clinical and laboratory criteria. Current criteria were created to identify patients with familial hemophagocytic lmyphohistiocytosis in immediate need of immunosuppressive therapy. However, these criteria also identify patients with infection-associated hemophagocytic inflammatory states lacking genetic defects typically predisposing to hemophagocytic lymphohistiocytosis. These patients include those with primary immunodeficiencies, in whom the pathogenesis of the inflammatory syndrome may be distinctive and aggressive immunosuppression is contraindicated. To better characterize hemophagocytic inflammation associated with immunodeficiencies, we combined an international survey with a literature search and identified 63 patients with primary immunodeficiencies other than cytotoxicity defects or X-linked lymphoproliferative disorders, presenting with conditions fulfilling current criteria for hemophagocytic lymphohistiocytosis. Twelve patients had severe combined immunodeficiency with <100/μL T cells, 18 had partial T-cell deficiencies; episodes of hemophagocytic lymphohistiocytosis were mostly associated with viral infections. Twenty-two patients had chronic granulomatous disease with hemophagocytic episodes mainly associated with bacterial infections. Compared to patients with cytotoxicity defects, patients with T-cell deficiencies had lower levels of soluble CD25 and higher ferritin concentrations. Other criteria for hemophagocytoc lymphohistiocytosis were not discriminative. Thus: (i) a hemophagocytic inflammatory syndrome fulfilling criteria for hemophagocytic lymphohistiocytosis can be the initial manifestation of primary immunodeficiencies; (ii) this syndrome can develop despite severe deficiency of T and NK cells, implying that the pathophysiology is distinct and not appropriately described as "lympho"-histiocytosis in these patients; and (iii) current criteria for hemophagocytoc lymphohistiocytosis are insufficient to differentiate hemophagocytic inflammatory syndromes with different pathogeneses. This is important because of implications for therapy, in particular for protocols targeting T cells.

Hematopoietic stem cell transplantation in thalassemia major and sickle cell disease: indications and management recommendations from an international expert panel

Thalassemia major and sickle cell disease are the two most widely disseminated hereditary hemoglobinopathies in the world. The outlook for affected individuals has improved in recent years due to advances in medical management in the prevention and treatment of complications. However, hematopoietic stem cell transplantation is still the only available curative option. The use of hematopoietic stem cell transplantation has been increasing, and outcomes today have substantially improved compared with the past three decades. Current experience world-wide is that more than 90% of patients now survive hematopoietic stem cell transplantation and disease-free survival is around 80%. However, only a few controlled trials have been reported, and decisions on patient selection for hematopoietic stem cell transplantation and transplant management remain principally dependent on data from retrospective analyses and on the clinical experience of the transplant centers. This consensus document from the European Blood and Marrow Transplantation Inborn Error Working Party and the Paediatric Diseases Working Party aims to report new data and provide consensus-based recommendations on indications for hematopoietic stem cell transplantation and transplant management.

Stem-Cell Transplantation in Children With Acute Lymphoblastic Leukemia: A Prospective International Multicenter Trial Comparing Sibling Donors With Matched Unrelated Donors—The ALL-SCT-BFM-2003 Trial

Purpose

Although hematopoietic stem-cell transplantation is widely performed in children with high-risk acute lymphoblastic leukemia (ALL), the influence of donor types is poorly understood. Thus, transplantation outcomes were compared in the prospective multinational Berlin-Frankfurt-Muenster (BFM) study group trial: ALL-SCT-BFM 2003 (Allogeneic Stem Cell Transplantation in Children and Adolescents with Acute Lymphoblastic Leukemia).

Patients and Methods

After conditioning with total-body irradiation and etoposide, 411 children with high-risk ALL received highly standardized stem-cell transplantations during the first or later remissions. Depending on donor availability, grafts originated from HLA-genoidentical siblings or from HLA-matched unrelated donors who were identified and matched by high-resolution allelic typing and were compatible in at least 9 of 10 HLA loci.

Results

Four-year event-free survival (± standard deviation [SD]) did not differ between patients with transplantations from unrelated or sibling donors (0.67 ± 0.03 v 0.71 ± 0.05; P = .405), with cumulative incidences of nonrelapse mortality (± SD) of 0.10 ± 0.02 and 0.03 ± 0.02 (P = .017) and relapse rates (± SD) of 0.22 ± 0.02 and 0.24 ± 0.04 (P = .732), respectively. Among recipients of transplantations from unrelated donors, no significant differences in event-free survival, overall survival, or nonrelapse mortality were observed between 9/10 and 10/10 matched grafts or between peripheral blood stem cells and bone marrow. The absence of chronic graft-versus-host disease had no effect on event-free survival. Engraftment was faster after bone marrow transplantation from siblings and was associated with fewer severe infections and pulmonary complications.

Conclusion

Outcome among high-risk pediatric patients with ALL after hematopoietic stem-cell transplantation was not affected by donor type. Standardized myeloablative conditioning produced a low incidence of treatment-related mortality and effective control of leukemia.

Multicenter experience in hematopoietic stem cell transplantation for serious complications of common variable immunodeficiency

BACKGROUND

Common variable immunodeficiency (CVID) is usually well controlled with immunoglobulin substitution and immunomodulatory drugs. A subgroup of patients has a complicated disease course with high mortality. For these patients, investigation of more invasive, potentially curative treatments, such as allogeneic hematopoietic stem cell transplantation (HSCT), is warranted.

OBJECTIVE

We sought to define the outcomes of HSCT for patients with CVID.

METHODS

Retrospective data were collected from 14 centers worldwide on patients with CVID receiving HSCT between 1993 and 2012.

RESULTS

Twenty-five patients with CVID, which was defined according to international criteria, aged 8 to 50 years at the time of transplantation were included in the study. The indication for HSCT was immunologic dysregulation in the majority of patients. The overall survival rate was 48%, and the survival rate for patients undergoing transplantation for lymphoma was 83%. The major causes of death were treatment-refractory graft-versus-host disease accompanied by poor immune reconstitution and infectious complications. Immunoglobulin substitution was stopped in 50% of surviving patients. In 92% of surviving patients, the condition constituting the indication for HSCT resolved.

CONCLUSION

This multicenter study demonstrated that HSCT in patients with CVID was beneficial in most surviving patients; however, there was a high mortality associated with the procedure. Therefore this therapeutic approach should only be considered in carefully selected patients in whom there has been extensive characterization of the immunologic and/or genetic defect underlying the CVID diagnosis. Criteria for patient selection, refinement of the transplantation protocol, and timing are needed for an improved outcome.

Diagnosis and treatment of adenovirus infection in immunocompromised patients

In immunocompromised patients, human adenovirus (HAdV) infections can cause life-threatening multiorgan disease. This review summarizes the incidence and risk factors of invasive human adenovirus infections in immunocompromised patients as well as the recently developed standards for diagnostic methods and strategies according to the predominant risk factors in adults and children. Recommendations for preemptive and therapeutic treatment strategies and the outcome in different risk groups are presented. Novel therapeutic approaches including CMX001, a new orally bioavailable lipid conjugate of cidofovir and the transfer of adenovirus-specific donor T cells in the context of allogeneic stem cell transplantation are discussed.

Stem cell transplantation after reduced-intensity conditioning for sickle cell disease

Sickle cell disease (SCD) is still associated with substantial morbidity and reduced life expectancy. Disease-related mortality rises to 14% in adolescents and young adults. Overall and disease-free survival following haematopoietic stem cell transplantation (HSCT) is 90% and 95%, respectively. To reduce transplant-associated late effects, the feasibility of a highly immunosuppressive reduced-intensity conditioning (RIC) regimen was explored in children with SCD and a matched sibling donor. Eight patients (median age, 9 yr) and symptomatic SCD were included. The conditioning regimen consisted of fludarabine, melphalan and either thiotepa or total lymphoid irradiation plus antithymocyte globuline or alemtuzumab. The graft was bone marrow in seven and cord blood in one case. The conditioning regimen was well tolerated and no severe infectious complications occurred. All patients displayed mixed chimaerism on day +28. After a median follow-up of 4 yr, 3/8 patients have mixed leucocyte chimaerism and 8/8 patients have 100% donor erythropoiesis. HSCT from matched sibling donors following a RIC regimen was well tolerated and resulted in cure in all patients studied. If confirmed in larger patient cohorts, these observations will have important implications for the indications of HSCT in children with SCD.

Clinical and immunological correction of DOCK8 deficiency by allogeneic hematopoietic stem cell transplantation following a reduced toxicity conditioning regimen

Dedicator of cytokinesis 8 protein (DOCK8) deficiency is a combined immunodeficiency disorder characterized by an expanding clinical picture with typical features of recurrent respiratory or gastrointestinal tract infections, atopic eczema, food allergies, chronic viral infections of the skin, and blood eosinophilia often accompanied by elevated serum IgE levels. The only definitive treatment option is allogeneic hematopoietic stem cell transplantation (HSCT). We report a patient with early severe manifestation of DOCK8 deficiency, who underwent unrelated allogeneic HSCT at the age of 3 years following a reduced toxicity conditioning regimen. The transplant course was complicated by pulmonary aspergilloma pretransplantation, adenovirus (ADV) reactivation, and cytomegalovirus (CMV) pneumonitis 4 weeks after transplantation. With antifungal and antiviral treatment the patient recovered. Seven months after transplantation the patient is in excellent clinical condition. Eczematous rash, chronic viral skin infections, and food allergies have subsided, associated with normalization of IgE levels and absolute numbers of eosinophils. Chimerism analysis shows stable full donor chimerism. DOCK8 deficiency can be successfully cured by allogeneic HSCT. This treatment option should be considered early after diagnosis, as opportunistic infections and malignancies that occur more frequently during the natural course of the disease are associated with higher morbidity and mortality.

Molecular diagnosis and management of viral infections in hematopoietic stem cell transplant recipients

Viral infections after allogeneic hematopoietic stem cell transplantation (HSCT) are important complications associated with high morbidity and mortality. In this setting, reactivations of persisting latent viral pathogens from donor and/or recipient cells play a central role whereas the sterile environment of transplant units renders new infections less likely. The viruses currently regarded as most relevant in the HSCT setting include particularly the herpes virus family--specifically cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpesvirus 6 (HHV-6)--as well as human adenoviruses (AdVs) and the polyoma virus BK (BKV). Timely detection and monitoring of virus copy numbers are prerequisites for successful preemptive treatment approaches. Pre- and post-transplant surveillance by sensitive and quantitative molecular methods has therefore become an essential part of the diagnostic routine. In this review, we discuss diagnostic aspects and the clinical management of the most important viral infections in HSCT recipients, with a focus on pediatric patients.

Defibrotide for prophylaxis of hepatic veno-occlusive disease in paediatric haemopoietic stem-cell transplantation: an open-label, phase 3, randomised controlled trial

BACKGROUND

Hepatic veno-occlusive disease is a leading cause of morbidity and mortality after haemopoietic stem-cell transplantation (HSCT). We aimed to assess whether defibrotide can reduce the incidence of veno-occlusive disease in this setting.

METHODS

In our phase 3 open-label, randomised controlled trial, we enrolled patients at 28 European university hospitals or academic medical centres. Eligible patients were younger than 18 years, had undergone myeloablative conditioning before allogeneic or autologous HSCT, and had one or more risk factor for veno-occlusive disease based on modified Seattle criteria. We centrally assigned eligible participants on the basis of a computer-generated randomisation sequence (1:1), stratified by centre and presence of osteopetrosis, to receive intravenous defibrotide prophylaxis (treatment group) or not (control group). The primary endpoint was incidence of veno-occlusive disease by 30 days after HSCT, adjudicated by a masked, independent review committee, in eligible patients who consented to randomisation (intention-to-treat population), and was assessed with a competing risk approach. Patients in either group who developed veno-occlusive disease received defibrotide for treatment. We assessed adverse events to 180 days after HSCT in all patients who received allocated prophylaxis. This trial is registered with ClinicalTrials.gov, number NCT00272948.

FINDINGS

Between Jan 25, 2006, and Jan 29, 2009, we enrolled 356 eligible patients to the intention-to-treat population. 22 (12%) of 180 patients randomly allocated to the defibrotide group had veno-occlusive disease by 30 days after HSCT compared with 35 (20%) of 176 controls (risk difference -7·7%, 95% CI -15·3 to -0·1; Z test for competing risk analysis p=0·0488; log-rank test p=0·0507). 154 (87%) of 177 patients in the defibrotide group had adverse events by day 180 compared with 155 (88%) of 176 controls.

INTERPRETATION

Defibrotide prophylaxis seems to reduce incidence of veno-occlusive disease and is well tolerated. Thus, such prophylaxis could present a useful clinical option for this serious complication of HSCT.

FUNDING

Gentium SpA, European Group for Blood and Marrow Transplantation.

Monitoring of adenovirus load in stool by real-time PCR permits early detection of impending invasive infection in patients after allogeneic stem cell transplantation

Invasive adenovirus (AdV) infections are associated with high morbidity and mortality in allogeneic stem cell transplant recipients. We observed that molecular detection of the virus in stool specimens commonly precedes AdV viremia, suggesting that intestinal infections may represent a common source of virus dissemination. To address this notion, we have investigated 153 consecutive allogeneic transplantations in 138 pediatric patients by quantitative monitoring of AdV in stool specimens and peripheral blood by a pan-adenovirus real-time (RQ)-PCR approach. AdV was detectable in serial stool specimens in all cases of AdV viremia during the post-transplant course (P<0.0001). The incidence of AdV viremia in individuals with peak virus levels in stool specimens above 1 x 10E6 copies per gram (n=22) was 73% vs 0% in patients with AdV levels in stool specimens below this threshold (n=29; P<0.0001). Serial measurement of AdV levels in stool specimens by RQ-PCR permitted early diagnosis of impending invasive infection with a sensitivity and specificity of 100% (95% confidence interval (CI) 96-100%) and 83% (95% CI 67-92%), respectively. The median time span between detection of AdV loads in stool specimens above 1 x 10E6 copies per gram and first observation of viremia was 11 days (range 0-192). Quantitative monitoring of the AdV load in stool specimens therefore provides a rationale for early initiation of antiviral treatment with the aim of preventing progression to life-threatening invasive infection.

Long-term outcome following hematopoietic stem-cell transplantation in Wiskott-Aldrich syndrome: collaborative study of the European Society for Immunodeficiencies and European Group for Blood and Marrow Transplantation

Wiskott-Aldrich syndrome (WAS) is a rare X-linked immunodeficiency with microthrombocytopenia, eczema, recurrent infections, autoimmune disorders, and malignancies that are life-threatening in the majority of patients. In this long-term, retrospective, multicenter study, we analyzed events that occurred in 96 WAS patients who received transplants between 1979 and 2001 who survived at least 2 years following hematopoietic stem-cell transplantation (HSCT). Events included chronic graft-versus-host disease (cGVHD), autoimmunity, infections, and sequelae of before or after HSCT complications. Three patients (3%) died 2.1 to 21 years following HSCT. Overall 7-year event-free survival rate was 75%. It was lower in recipients of mismatched related donors, also in relation with an older age at HSCT and disease severity. The most striking finding was the observation of cGVHD-independent autoimmunity in 20% of patients strongly associated with a mixed/split chimerism status (P < .001), suggesting that residual-host lymphocytes can mediate autoimmune disease despite the coexistence of donor lymphocytes. Infectious complications (6%) related to splenectomy were also significant and may warrant a more restrictive approach to performing splenectomy in WAS patients. Overall, this study provides the basis for a prospective, standardized, and more in-depth detailed analysis of chimerism and events in long-term follow-up of WAS patients who receive transplants to design better-adapted therapeutic strategies.

Importance of allogeneic T-cells for disease control after stem cell transplantation for high-risk Langerhans cell histiocytosis

Reduced intensity conditioning followed by allogeneic SCT (RIC-SCT) has recently emerged as promising new salvage option for children suffering from Langerhans cell histiocytosis (LCH) with risk organ involvement and failure to conventional therapy. We report on the posttransplant course of female toddler with high-risk LCH, who achieved complete remission after RIC-SCT, despite a posttransplant chimerism constellation, in which only the T-cell subset proved to be of donor origin in the long-term. We therefore suggest that allogeneic T-cells have played a crucial role in controlling disease activity in this patient and may exert the major curative effect after RIC-SCT for LCH.

Safe adoptive transfer of virus-specific T-cell immunity for the treatment of systemic adenovirus infection after allogeneic stem cell transplantation

During periods of immunosuppression, such as postallogeneic stem cell transplantation (SCT), patients are at significant risk for severe viral infections. Human adenovirus (HAdV) infection is a serious complication post-SCT, especially in children. Virus-specific T cells are essential for the clearance of HAdV, as antiviral chemotherapy has revealed limited success. We present feasibility data for a new treatment option using virus-specific donor T cells for adoptive transfer of immunity to patients with HAdV-infection/reactivation. Virus-specific donor T cells were isolated and infused into nine children with systemic HAdV infection after SCT. Isolation was based on gamma-interferon (IFN-gamma) secretion after short in vitro stimulation with viral antigen, resulting in a combination of CD4(+) and CD8(+) T cells. 1.2-50 x 10(3)/kg T cells were infused for adoptive transfer. Isolated cells showed high specificity and markedly reduced alloreactivity in vitro. Adoptive transfer of HAdV-specific immunity was successful in five of six evaluable patients, documented by a dose-independent and sustained in vivo expansion of HAdV-specific T cells, associated with a durable clearance/decrease of viral copies. T-cell infusion was well tolerated in all nine patients, except one case with graft-versus-host disease II of the skin. In conclusion, induction of a specific T-cell response through adoptive transfer was feasible and effective. When performed early in the course of infection, adoptive T-cell transfer may protect from HAdV-related complications.

Defective regulatory and effector T cell functions in patients with FOXP3 mutations

The autoimmune disease immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) is caused by mutations in the forkhead box protein P3 (FOXP3) gene. In the mouse model of FOXP3 deficiency, the lack of CD4+ CD25+ Tregs is responsible for lethal autoimmunity, indicating that FOXP3 is required for the differentiation of this Treg subset. We show that the number and phenotype of CD4+ CD25+ T cells from IPEX patients are comparable to those of normal donors. CD4+ CD25high T cells from IPEX patients who express FOXP3 protein suppressed the in vitro proliferation of effector T cells from normal donors, when activated by "weak" TCR stimuli. In contrast, the suppressive function of CD4+ CD25high T cells from IPEX patients who do not express FOXP3 protein was profoundly impaired. Importantly, CD4+ CD25high T cells from either FOXP3+ or FOXP3- IPEX patients showed altered suppression toward autologous effector T cells. Interestingly, IL-2 and IFN-gamma production by PBMCs from IPEX patients was significantly decreased. These findings indicate that FOXP3 mutations in IPEX patients result in heterogeneous biological abnormalities, leading not necessarily to a lack of differentiation of CD4+ CD25high Tregs but rather to a dysfunction in these cells and in effector T cells.

In vitro and in vivo T-cell depletion with myeloablative or reduced-intensity conditioning in pediatric hematopoietic stem cell transplantation

BACKGROUND AND OBJECTIVES

Anti-thymocyte globulin (ATG) is given in various conditioning regimens for children and young adults undergoing hematopoietic stem cell transplantation (HSCT) from HLA non-identical donors in order to reduce the risks of graft-versus-host disease (GvHD) and rejection after the transplant. The aim of this study was to define the effect of in vitro T-cell depletion in addition to ATG on the reconstitution of T-cell-mediated immunity.

DESIGN AND METHODS

We retrospectively analyzed the engraftment kinetics and clinical performance of 134 patients (median age 5.80 years) who received ATG during myeloablative or reduced intensity conditioning, and either in vitro T-cell-depleted or unmanipulated grafts.

RESULTS

T-cell reconstitution was significantly delayed after T-cell-depleted grafts, irrespectively of the conditioning intensity (p<0.001). The incidence of fatal viral and fungal infections was higher in recipients of T-cell-depleted grafts than in those receiving unmanipulated grafts (26.6-29% versus <or=13%). The rejection rate was likewise higher in recipients of T-cell-depleted grafts whether following myeloablative or reduced intensity conditioning (37% and 18%, associated with recipient chimerism or non-engraftment, respectively) versus <or=4% without graft T-cell depletion. Grades 3 and 4 acute GvHD (CI+/-SE <or=0.11+/-0.03) and severe Epstein-Barr virus lymphoproliferative disease (1.49% fatal) were rare.

INTERPRETATION AND CONCLUSIONS

A combination of ex vivo and in vivo T-cell depletion, although inhibiting GvHD, prolongs the interval of T cell deficiency after HSCT and favors rejection and infections, implying that the requirement for this type of extensive T-cell depletion should be carefully re-evaluated.

Antithymocyte globulin pharmacokinetics in pediatric patients after hematopoietic stem cell transplantation

To analyze the dose effects of rabbit-derived antithymocyte globulin (ATG) in children after allogeneic hematopoietic stem cell transplantation (HSCT), ATG serum levels were monitored in 32 children and adolescents (median age 3.42 years, range 0.34-18.67 years) and the incidence of acute and chronic graft-versus-host disease, rejection, viral infections, EBV-lymphoproliferative disease, and survival was correlated with the ATG dose used. Cumulative doses from 7.5 to 20 mg/kg showed a constant half-life and linear correlation between dose and Cmax, whereas higher doses (30-40 mg/kg) accumulated in the body. High-dose ATG is of no benefit for preventing graft-versus-host disease but is associated with a significant increase in EBV-linked disease, and it appears to enhance the susceptibility to fatal viral infections and rejection. These data strongly support the use of a low-dose ATG regimen in pediatric HSCT.

Improved outcome of treatment-resistant high-risk Langerhans cell histiocytosis after allogeneic stem cell transplantation with reduced-intensity conditioning

Children with multisystem Langerhans cell histiocytosis (LCH) and risk organ involvement who fail to respond to conventional chemotherapy have an extremely poor prognosis. Myeloablative stem cell transplantation (SCT) as a possible salvage approach for these patients has been associated with a high risk of transplant-related mortality. Therefore, allogeneic stem cell transplantation following a reduced-intensity conditioning regimen (RIC-SCT) has recently been performed as an alternative salvage approach. We report on the experience with allogeneic RIC-SCT in nine pediatric high-risk LCH patients. Conditioning regimen included fludarabine in all patients, melphalan in eight patients, total lymphoid irradiation in six patients, total body irradiation in two, antithymocyte globulin in five, and Campath in four patients. RIC-SCT was well tolerated with regard to common procedure-related complications. Two patients died 50 and 69 days after RIC-SCT, respectively. Seven out of the nine patients survived and showed no signs of disease activity (including one with nonengraftment and full autologous hematopoietic recovery) after median follow-up of 390 days post-SCT. Based on this observation, we conclude that RIC-SCT is a feasible procedure with low transplant-related morbidity and mortality and a promising new salvage approach for high-risk LCH patients with resistant risk organ involvement.

Donor leukocyte infusion after hematopoietic stem cell transplantation in patients with juvenile myelomonocytic leukemia

Juvenile myelomonocytic leukemia (JMML) is a clonal myeloproliferative disorder of early childhood. In all, 21 patients with JMML who received donor leukocyte infusion (DLI) after allogeneic hematopoietic stem cell transplantation (HSCT) for either mixed chimerism (MC, n=7) or relapse (n=14) were studied. Six patients had been transplanted from an HLA-matched sibling and 15 from other donors. Six of the 21 patients (MC: 3/7 patients; relapse: 3/14 patients) responded to DLI. Response rate was significantly higher in patients receiving a higher total T-cell dose (> or =1 x 10(7)/kg) and in patients with an abnormal karyotype. None of the six patients receiving DLI from a matched sibling responded. Response was observed in five of six patients who did and in one of 15 children who did not develop acute graft-versus-host disease following DLI (P=0.01). The overall outcome was poor even for the responders. Only one of the responders is alive in remission, two relapsed, and three died of complications. In conclusion, this study shows that some cases of JMML may be sensitive to DLI, this providing evidence for a graft-versus-leukemia effect in JMML. Infusion of a high number of T cells, strategies to reduce toxicity, and cytoreduction prior to DLI may improve the results.

Treatment of CD40 ligand deficiency by hematopoietic stem cell transplantation: a survey of the European experience, 1993-2002

CD40 ligand (CD40L) deficiency causes recurrent sinopulmonary infection, Pneumocystis carinii pneumonia, and Cryptosporidium parvum infection. Approximately 40% to 50% of patients survive to the third decade: long-term survival is unclear. Hematopoietic stem cell transplantation (HSCT) is curative. We present a retrospective analysis of 38 European patients undergoing HSCT for CD40L deficiency in 8 European countries between 1993 and 2002. Donor stem cell source included 14 HLA-identical siblings, 22 unrelated donors, and 2 phenotypically matched parental stem cells (12 T-cell depleted). Of the patients, 34 engrafted and 26 (68%) survived; 3 had autologous reconstitution, 22 (58%) were cured, and 1 engrafted but has poor T-cell immune reconstitution. There were 18 evaluated patients who responded to vaccination. Of the patients, 12 (32%) died from infection-related complications, with severe cryptosporidiosis in 6. Grades 2 to 4 graft-versus-host disease (GvHD) associated with infection occurred in 6 of 12 fatal cases. HSCT cured 58% of patients, 72% of those without hepatic disease. Early T-cell function following whole marrow HSCT may limit cryptosporidial disease, but survival was similar after T-cell-depleted HSCT. Preexisting lung damage was the most important adverse risk factor. Further studies will determine optimal timing and type of HSCT.

Lineage-specific chimaerism after stem cell transplantation in children following reduced intensity conditioning: potential predictive value of NK cell chimaerism for late graft rejection

Chimaerism of FACS-sorted leucocyte subsets (CD14+, CD15+, CD3-/56+, CD3+/4+, CD3+/8+, CD19+) was monitored prospectively between days +14 and +100 in 39 children undergoing allogeneic stem cell transplantation with reduced intensity-conditioning regimens. Cell subsets exceeding 1% of nucleated cells were subject to cell sorting. Chimaerism was analysed by dual-colour FISH and/or by short tandem repeat-polymerase chain reaction. The chimaerism pattern on day +28 was evaluated with regard to its correlation with graft rejection. Of 39 patients, nine patients had donor chimaerism (DC) in all subsets. Mixed/recipient chimaerism (MC/RC) was detectable within T cells in 62%, within NK cells in 39% and within monocytes and granulocytes in 38% of the patients. The correlation of secondary graft rejection with the chimaerism pattern on day +28 revealed the strongest association between RC in NK-cells (P<0.0001), followed by T cells (P=0.001), and granulocytes and monocytes (P=0.034). Notably, patients with RC in T cells rejected their graft only if MC or RC was also present in the NK-cell subset. By contrast, none of the children with DC in NK cells experienced a graft rejection. These observations suggest that, in the presence of recipient T-cell chimaerism, the chimaerism status in NK-cells on day +28 might be able to identify patients at high risk for late graft rejection.

Molecular monitoring of adenovirus in peripheral blood after allogeneic bone marrow transplantation permits early diagnosis of disseminated disease

Adenovirus (AdV) infection in the course of allogeneic stem cell transplantation (SCT) is associated with high transplant-related morbidity and mortality. Disseminated AdV disease is lethal in most instances. Early detection of AdV infection and identification of patients carrying a high risk of disseminated disease therefore remain a major challenge. In view of the large number of existing AdV types, we have established real-time polymerase chain reaction (PCR) assays permitting sensitive detection and quantification of all 51 currently known human AdV serotypes. In a series of 132 consecutive pediatric patients undergoing SCT, more than 5000 samples derived from peripheral blood (PB), stool, urine, and throat were screened for adenovirus infection by PCR during the posttransplantation period. Thirty-six patients (27%) tested positive by PCR, revealing AdV types of the subgenera A, B, C, D, and F. Except for enteritis in some patients with AdV positivity in stool, detection of the virus at sites other than PB was not associated with clinical signs of virus disease, and transplant-related mortality was not significantly different from AdV-negative patients. By contrast, 82% of patients who had detectable AdV in PB died from infectious complications (P <.001). Monitoring of PB specimens by real-time PCR permitted early diagnosis of invasive AdV infection in all instances. In patients who developed disseminated AdV disease, detection of the virus in PB preceded onset of clinical symptoms by a median of more than 3 weeks. The observation of AdV in peripheral blood may therefore serve as a basis for early initiation of preemptive antiviral treatment.

Pre-emptive treatment of CMV DNAemia in paediatric stem cell transplantation: the impact of recipient and donor CMV serostatus on the incidence of CMV disease and CMV-related mortality

Cytomegalovirus (CMV) DNAemia was detected by PCR in 30/125 (24%) consecutive paediatric patients undergoing allogeneic stem cell transplantation. All patients with CMV DNAemia received pre-emptive ganciclovir until two consecutive negative results were obtained. CMV-IgG-positive patients (R+) had a significantly increased risk of DNAemia as compared to CMV-IgG-negative (R-) patients (62% vs 8%) P<0.0001. The incidence of DNAemia was 71% (10/14) in R+ transplanted from seronegative donors (D-) compared to 54% (13/32) in those transplanted from seropositive donors (D+). Of 30 (40%) children with DNAemia, 12 developed CMV disease despite pre-emptive treatment. The overall incidence of disease was 0% (0/59) for R-/D-, 9% (3/23) for R+/D+, 7% (2/29) for R-/D+ and 57% (8/14) for R+/D-. In patients with DNAemia, 4/20 (20%) patients with D+ and 8/10 (80%) with D- became symptomatic. In the multivariate analysis of both groups, patients at risk (R+ and/or D+) and patients with DNAemia, a negative donor serostatus was the only factor associated with a significantly increased incidence of disease. Seven of 9 patients with lethal CMV disease had received CMV-IgG-negative grafts. The data suggest that in CMV seropositive recipients donor CMV seropositivity is associated with a reduced incidence of CMV disease and a favourable outcome following pre-emptive treatment.

Cidofovir for adenovirus infections after allogeneic hematopoietic stem cell transplantation: a survey by the Infectious Diseases Working Party of the European Group for Blood and Marrow Transplantation

Adenovirus is an important cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation and there is no established therapy. Cidofovir has in vitro efficacy against adenovirus. We performed a retrospective analysis of 45 patients treated with cidofovir for adenovirus from 10 centers. In total, 16 patients had definite adenovirus disease, 13 probable disease, and 16 asymptomatic infections. A total of 31 (69%) patients were successfully treated with cidofovir, 10 failed, and four were not evaluable owing to early death from other causes. Cidofovir therapy was successful in 10 patients with adenovirus disease, 10 patients with probable disease, and in 10 patients with asymptomatic infections. The overall survival at 28 days and 6 months after initiation of cidofovir therapy was 76 and 46%, respectively. Of the patients, 18 developed toxicity associated with cidofovir: 14 developed renal toxicity and four other types of toxicities. We conclude that cidofovir may be useful against adenovirus after allogeneic hematopoietic stem cell transplantation but additional studies are needed.

Adenovirus DNA in serum of children hospitalized due to an acute respiratory adenovirus infection

Serum samples from 68 immunocompetent infants (mean age, 12.6 months) with an acute adenovirus infection of the respiratory tract (39 experiencing their first adenovirus infection) were tested for the presence of adenovirus DNA, to investigate whether viral dissemination via the blood is usually present in the immunocompetent patient. Using a nested polymerase chain reaction assay, adenovirus DNA could be detected in acute-phase serum samples from 28 (41%) children. Adenovirus DNA was never found in follow-up serum samples, indicating a short period ( approximately 1 week) of viral dissemination. In children experiencing their first adenovirus infection, viral DNA could be detected in 72% of the acute-phase serum samples collected within the first week after onset of symptoms. Adenovirus DNA could also be detected in 25% of the acute-phase serum samples from patients with reinfection.

Influence of transplantation regimen on prognostic significance of high-level minimal residual disease before allogeneic stem cell transplantation in children with ALL

High MRD levels before transplantation in children receiving T cell-depleted unrelated grafts for relapsed ALL were associated with a 100% relapse risk. We report on two children with relapsed ALL who underwent non T cell-depleted BMT from unrelated donors. Despite a high residual tumor load pre- transplant and the occurrence of only aGVHD grade I, they are still in second complete remission 2.7 and 5.2 years after transplantation, respectively. Thus, we propose that the transplant regimens influence the prognostic significance of high MRD levels pre-BMT.

Allogeneic bone marrow transplantation-mediated transfer of specific immunity against Toxocara canis associated with excessive IgE

A girl with myelodysplastic syndrome (RAEB-T) received HLA-identical bone marrow from her younger brother after myeloablative treatment with busulfan and cyclophosphamide. After bone marrow transplantation, fever, exanthema, pruritus, and a pulmonary infiltrate were treated symptomatically. Bacterial cultures remained negative. Leukocyte engraftment began on day 10, and all blood cell populations proved to be of donor origin on FISH analysis. Increasing IgE levels (21 000 U/ml) on day 14 after BMT, positive RAST, specific IgG-antibodies, and missing Toxocara (T.) canis antigens in the recipient indicated donor-derived seroconversion. Before BMT, the recipient had been negative for T. canis in routine parasitological screening, and the donor proved to be positive for T. canis antibody by ELISA. This report suggests that the transfer of IgE immunity in the absence of detectable antigens may be responsible for IgE-mediated symptoms consistent with toxocara infection and confirms the need for parasite screening in donor medical examinations.

Cidofovir for cytomegalovirus infection and disease in allogeneic stem cell transplant recipients. The Infectious Diseases Working Party of the European Group for Blood and Marrow Transplantation

A retrospective study was performed to collect information regarding efficacy and toxicity of cidofovir (CDV) in allogeneic stem cell transplant patients. Data were available on 82 patients. The indications for therapy were cytomegalovirus (CMV) disease in 20 patients, primary preemptive therapy in 24 patients, and secondary preemptive therapy in 38 patients. Of the patients, 47 had received previous antiviral therapy with ganciclovir, foscarnet, or both drugs. The dosage of CDV was 1 to 5 mg/kg per week followed by maintenance every other week in some patients. The duration of therapy ranged from 1 to 134 days (median, 22 days). All patients received probenecid and prehydration. Ten of 20 (50%) patients who were treated for CMV disease (9 of 16 with pneumonia) responded to CDV therapy, as did 25 of 38 (66%) patients who had failed or relapsed after previous preemptive therapy and 15 of 24 (62%) patients in whom CDV was used as the primary preemptive therapy. Of the patients, 21 (25.6%) developed renal toxicity that remained after cessation of therapy in 12 patients. Fifteen patients developed other toxicities that were potentially due to CDV or the concomitantly given probenecid. No toxicity was seen in 45 (61.6%) patients. Cidofovir can be considered as second-line therapy in patients with CMV disease failing previous antiviral therapy. However, additional studies are needed before CDV can be recommended for preemptive therapy.

Successful stem cell transplantation following orthotopic liver transplantation from the same haploidentical family donor in a girl with hemophagocytic lymphohistiocytosis

The case of a 4-month-old girl with familial hemophagocytic lymphohistiocytosis is described. The patient underwent stem cell transplantation from her haploidentical mother 2 months after receiving a living-related liver transplant from the same donor for acute hepatic failure. Conditioning regimen consisted of 16 mg/kg busulfan, 200 mg/kg cyclophosphamide, 10 mg/kg thiothepa, and antithymocyte globulin. Myeloid engraftment occurred on day +10, but CD3(+) cells of recipient origin remained. To convert the T-cell chimerism, the patient received donor lymphocyte infusion on day +43, and subsequently the allelic pattern changed to complete donor genotype on day +57. Four months after stem cell transplantation the patient is disease free, with complete donor chimerism in bone marrow and stable hepatic graft function without any immunosuppressive therapy. (Blood. 2000;96:3997-3999)

Allogeneic bone marrow transplantation for juvenile myelomonocytic leukaemia: a single centre experience and review of the literature

Juvenile myelomonocytic leukaemia (JMML) is a rare paediatric disease and allogeneic stem cell transplantation is the only curative approach. The roles of pretransplant treatment, conditioning regimen and graft-versus-host disease (GVHD) are still unclear. Eleven children with JMML underwent allogeneic BMT in our institution. Donors were matched unrelated (n = 6) matched siblings (n = 4) and one mismatch family donor. Transplant-related mortality (TRM) was 36%. Three patients relapsed after transplantation. Two of three patients with relapse are in continuous remission after donor lymphocyte infusion or second BMT, respectively. To evaluate the role of pretransplant treatment, conditioning regimen and GVHD, we have summarised our series with other published single centre reports and give an overview on a total of 65 patients with JMML who underwent allogeneic BMT. No significant correlation between pretransplant treatment, conditioning regimen and TRM could be observed. Overall relapse rate is high (47%). TBI is associated with a significantly higher relapse rate (P = 0.012). Other conditioning modalities, intensive chemotherapy and splenectomy prior to stem cell transplantation do not seem to have a significant impact on relapse rate. Patients with or without GVHD showed no significant difference in relapse rate (58% vs 45%). In the event of relapse after transplantation withdrawal of immunosuppression, donor lymphocyte infusion or second transplant was successful in 6/11 patients. Graft-versus-leukaemia effect seems to play an essential role in bone marrow transplantation for JMML.

Leucocyte transfusions from rhG-CSF or prednisolone stimulated donors for treatment of severe infections in immunocompromised neutropenic patients

Sepsis in profound neutropenia after chemotherapy is associated with high mortality despite appropriate antibacterial or antifungal treatment. In a prospective phase I/II study we evaluated the feasability and efficacy of leucocyte transfusions (LT) in patients with malignancies or haematological disorders who were suffering from severe bacterial or fungal infection during therapy-related bone marrow aplasia. 30 patients with severe neutropenia and clinical signs of life-threatening sepsis not responding to adequate treatment, received LT from rhG-CSF-stimulated family donors or from prednisolone-primed volunteers. A total of 301 LT were administered. The median number of LT per patient was seven (range three to 65), the median duration of LT treatment was 8 d (range 2-35). The white cell count (WBC), absolute neutrophil count (ANC) and lymphocyte count of the concentrates from rhG-CSF-stimulated donors were significantly higher than those from prednisolone-primed volunteers (P = 0.0001). Despite the critical condition of the patients, LT were generally well tolerated. Only 39 (12.9%) LT were associated with adverse reactions. The transfusion of leucocytes collected by continuous flow leukapheresis from both rhG-CSF and prednisolone stimulated donors resulted in a measurable increment of the peripheral leucocyte and ANC counts in our patients. On day 100 after the first LT, 20/30 patients were alive with complete clearance of the infection.