IntroductionCeliac disease (CD) is an autoimmune enteropathy triggered by gluten ingestion in genetically susceptible individuals. The haplotypes HLA-DQ2 and DQ8, transglutaminase (TGA) antibodies, and biopsy findings are the main tests performed in the evaluation and CD diagnosis. The objective was to establish possible correlations between transglutaminase levels, genetic markers tests, and qualitative intestinal biopsy findings (modified Marsh classification) at the diagnosis.MethodsA retrospective cohort study. The selection criteria were confirmed CD cases with genetic tests performed. Statistical analysis was done mainly through One-way ANOVA, Kendall's correlation coefficient (T), and linear regression.ResultsThe study included 112 patients, with a mean age of 6 ± 4 years. All cases were tested to HLA-DQ2, and it was positive in 93%. HLA-DQ8 was tested in 73% of cases and it was positive in 61%. The percentage of negative genetic markers (DQ2/DQ8) was 4.5% for patients tested to both haplotypes. A comparison of DQ2/DQ8 (positive and negative) with clinical findings and tests performed did not identify any differences for most of the parameters analyzed. Cases of type I diabetes presented significant negative expression for DQ2(−); p = 0.05 and positive expression for DQ8(+); p = 0.023. The TGA antibody levels ranged from 18 to 36,745 U/ml. An inverse correlation was found between age and TGA-L level (p = 0.043). In 23% of the cases, the TGA levels were greater than 1,000 U/ml and presented a moderate positive correlation with the atrophy biopsy profile (T = 0.245). Patients with an atrophic biopsy profile (Marsh III) had a moderate positive correlation with growth failure (T = 0.218) but a negative correlation with constipation (T = −0.277).ConclusionIn terms of diagnosis tests for CD, transglutaminase levels and age presented an inverse correlation, with the level decreasing as age increased. A moderately positive correlation was found between mean transglutaminase with intestinal atrophy and growth retardation. The genetic test DQ2 was positive for 93% and negative genetic markers (DQ2/DQ8) represented 4.5% of cases studied.

Haploidentical stem cell transplantation (Haplo-SCT) and cord blood transplantation (CBT) are both effective alternative treatments in patients suffering from acute myeloid leukemia (AML) and lacking a matched HLA donor. In the last years, many centers have abandoned CBT procedures mostly due to concern about poorer immune recovery compared with Haplo-SCT. We conducted a retrospective multicenter study comparing the outcomes using both alternative approaches in AML. A total of 122 transplants (86 Haplo-SCTs and 36 CBTs) from 12 Spanish centers were collected from 2007 to 2021. Median age at hematopoietic stem cell transplantation (HSCT) was 7 years (0.4-20). Thirty-nine patients (31.9%) showed positive minimal residual disease (MRD) at HSCT and a previous HSCT was performed in 37 patients (30.3%). The median infused cellularity was 14.4 x 10(6)/kg CD34+ cells (6.0-22.07) for Haplo-SCT and 4.74 x 10(5)/kg CD34+ cells (0.8-9.4) for CBT. Median time to neutrophil engraftment was 14 days (7-44) for Haplo-SCT and 17 days (8-29) for CBT (P = .03). The median time to platelet engraftment was 14 days (6-70) for Haplo-SCT and 43 days (10-151) for CBT (P < .001). Graft rejection was observed in 13 Haplo-SCTs (15%) and in 6 CBTs (16%). The cumulative incidence of acute graft versus host disease (GvHD) grades II-IV was 54% and 51% for Haplo-SCT and CBT, respectively (P = .50). The cumulative incidence of severe acute GvHD (grades III-IV) was 22% for Haplo-SCT and 25% for CBT (P = .90). There was a tendency to a higher risk of chronic GvHD in the Haplo-SCT group being the cumulative incidence of 30% for Haplo-SCT and 12% for CBT (P = .09). The cumulative incidence of relapse was 28% and 20% for Haplo-SCT and CBT, respectively (P = .60). We did not observe statistically significant differences in outcome measures between Haplo-SCT and CBT procedures: 5-year overall survival (OS) was 64% versus 57% (P = .50), 5-year disease-free survival (DFS) 58% versus 57% (P = .80), GvHD-free and relapse-free survival (GFRFS) 41% versus 54% (P = .30), and cumulative incidence of transplant-related mortality (TRM) 14% versus 15% (P = .80), respectively. In the multivariate analysis, MRD positivity and a disease status >CR1 at the time of HSCT were significantly associated with poorer outcomes (P < .05). In conclusion, our study supports that both haploidentical and cord blood transplantation show comparable outcomes in pediatric AML patients. We obtained comparable survival rates, although CBT showed a trend to lower rates of chronic GvHD and higher GFRFS, demonstrating that it should still be considered a valuable option, particularly for pediatric patients. (c) 2024 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Background Natural Killer (NK) cells play a crucial role in the graft-versus-leukemia effect during haploidentical hematopoietic stem cell transplantation (Haplo-HSCT). Alloreactive NK cells are associated with lower relapse rates, improved engraftment, reduced graft-versus-host disease (GvHD), and decreased viral infection risk. However, not all Haplo-HSCT cases exhibit KIR-HLA incompatibility between donor and recipient. Ex vivo stimulation of NK cells with IL-15 could overcome inhibitory signals. This study aims to evaluate the safety and effectiveness of a single dose of alloreactive or ex vivo NK cells stimulated with IL-15 after Haplo-HSCT. Methods Eighteen pediatric patients with high-risk hematological malignancies, transplanted with a haploidentical donor, were enrolled in a prospective, multicenter phase I/II clinical trial. On day +7 after Haplo-HSCT, alloreactive NK cells (n=9) or non-alloreactive but ex vivo overnight IL-15-activated NK cells (n=9) were infused. The NK cell immunophenotype, K562 cytotoxicity, CD107a degranulation in the infused products, and the clinical outcomes, immune reconstitution, and cytokine profile in the patients were analyzed at different time points over the course of one year following Haplo-HSCT. Results Ex vivo stimulated L15-NK cells in the infusion product showed higher expression of activating receptors (NKp46, NKp44, NKG2D, CD69) and higher functional capacity than Allo-NK cells. No differences between arms were found in the NK cell phenotype and the functional capacity over time following Haplo-HSCT changes in pediatric patients. Seventeen patients successfully engrafted. The 1-year cumulative incidence (CI) of grade I-II acute GvHD was significantly higher in patients treated with IL-15 NK cells compared to Allo-NK cells (56% vs. 11%, p=0.04). However, similar CI of grade III-IV acute GvHD was observed between the two NK cell infusion groups. The 1-year CI of chronic GvHD was 35% (95% CI: 13%-57%). The 1-year overall survival (OS) and diseased-free-survival (DFS) were 77% (95% CI: 60%-99%), and GVHD-free relapse-free survival (GRFS) was 61% (95% CI: 42%-88%), without differences between both groups. The 1-year CI of relapse and transplant related mortality (TRM) for all patients were 5.6% (95% CI: 0.3%-23%) and 17% (95% CI: 3.9%-38%), respectively. Regardless the type of NK infusion, patients presented rapid immune reconstitution. In the IL-15 NK arm, median CD3+ T-cell counts showed a higher trend (671 cells/μL) than in the Allo-NK arm (406 cells/μL) in the first month after Haplo-HSCT and persisted at subsequent time points. However, NK cells showed a trend towards higher expression levels in the Allo-NK arm at 1-month (median: 307 cells/μL) and 6-months post-transplant (median: 242 cells/μL) compared to the IL-15 NK arm (median: 181 cells/μL and median: 196 cells/μL, respectively). A statistically significant increase in IL-2, IL-17A, and IL-13 at 1 month, as well as in IFN-γ, IL-6, IL-4, IL-9, IL-2, IL-10, IL-17A and IL-13 at 12 months after transplantation, was observed in plasma levels into IL-15 NK arm compared to the Allo-NK arm . In addition, we observed a correlation between higher CD69 expression in total NK cells and an increase in TRM and GvHD. Patients who expressed CD69 on NK cells below the established threshold of 21% at 6 months post-Haplo-HSCT exhibited statistically significant improvements in OS and GRFS, along with a trend towards improved DFS. Conclusion Infusion of ex vivo IL-15-stimulated NK cells after Haplo-HSCT was as safe and effective as alloreactive NK cells. T cell immune recovery was faster, and cytokine inflammatory responses were higher compared to alloreactive NK cells. In addition, a higher expression of CD69 on NK cells could be used as a biomarker for TRM.

BACKGROUND:Neurological complications (NCs) are of major concern following hematological stem cell transplantation (HSCT), most of which present with seizures. PROCEDURES:We performed a retrospective study (2002-2018) of patients undergoing HSCT in order to analyze the incidence and aetiologies related to seizures. RESULTS:Of 155 children undergoing HSCT, 27 (17.4%) developed seizures at some point in 2 years of follow-up. The most frequent etiologies were central nervous system (CNS) infection (n = 10), drug toxicity (n = 8), and vascular disease (n = 5). A statistically significant association was found between seizure and the HSCT type (lower risk for a related identical donor, p = .010), prophylactic or therapeutic mycophenolate use (p = .043 and .046, respectively), steroid use (p = .023), selective CD45RA+ depletion (p = .002), pre-engraftment syndrome (p = .007), and chronic graft-versus-host disease (GVHD) severity (p = .030). Seizures predicted evolution to life-threatening complications and admission to intensive care (p < .001) and higher mortality (p = .023). A statistically significant association was also found between seizures and sequelae in survivors (p = .029). Children who developed seizures had a higher risk of CNS infection and vascular disease (odds ratio 37.25 [95% CI: 7.45-186.05] and 12.95 [95% CI 2.24-74.80], respectively). CONCLUSIONS:Neurological complications highly impact survival and outcomes and need to be addressed when facing an HSCT procedure.

Fanconi anemia (FA) is a rare genetic disease characterized by high phenotypic and genotypic heterogeneity, and extreme chromosome fragility. To better understand the natural history of FA, identify genetic risk and prognostic factors, and develop novel therapeutic strategies, the Spanish Registry of Patients with FA collects data on clinical features, chromosome fragility, genetic subtypes, and DNA sequencing with informed consent of participating individuals. In this article, we describe the clinical evolution of 227 patients followed up for up to 30 years, for whom our data indicate a cumulative cancer incidence of 86% by age 50. We found that patients with lower chromosome fragility had a milder malformation spectrum and better outcomes in terms of later-onset hematologic impairment, less severe bone marrow failure, and lower cancer risk. We also found that outcomes were better for patients with mutations leading to mutant FANCA protein expression (genetic hypomorphism) than for patients lacking this protein. Likewise, prognosis was consistently better for patients with biallelic mutations in FANCD2 (mainly hypomorphic mutations) than for patients with biallelic mutations in FANCA and FANCG , with the lack of the mutant protein in patients with biallelic mutations in FANCG contributing to their poorer outcomes. Our results regarding the clinical impact of chromosome fragility and genetic hypomorphism suggest that mutant FA proteins retain residual activity. This finding should encourage the development of novel therapeutic strategies aimed at partially or fully enhancing mutant FA function, thereby preventing or delaying bone marrow failure and cancer in patients with FA. Clinical Trial Registration number: NCT06490510.

Background: Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is a highly complicated but effective procedure for high-risk pediatric leukemia in the absence of an HLA-identical donor. Post-transplant relapse is the main problem for patient survival. According to literature, Natural Killer (NK) cells play a potent role as inducers of the graft-versus-leukemia (GvL) effect in haplo-HSCT. The presence of alloreactive NK cells correlates with a lower relapse rate, improved engraftment, decreasing graft-versus-recipient disease (GvHD) and viral infection risk. In the absence of donor-recipient NK cell alloreactivity, other NK cell activation strategies are necessary. We propose a phase I/II clinical trial with dose escalation, multicenter, framed in the GETH, to determine dose-limiting toxicity (DLT) and the maximum tolerated dose (MTD) of a single infusion of alloreactive NK cells (Allo-NK) or NK cells stimulated ex vivo with IL-15 (IL15-NK) after haplo-HSCT in pediatric patients with high-risk leukemias. Methods: Eighteen pediatric patients with high-risk leukemia were recruited between September 16, 2020, and May 12, 2023, at 5 hospitals in Spain, Hospital Universitario La Paz, Hospital Universitario Gregorio Marañón, Hospital Universitario Niño Jesús, Hospital Universitario Central of Asturias and Hospital Santa Creu and Sant Pau. Patients were stratified in 2 treatment groups: Allo-NK (n=9) or IL15-NK (n=9), depending on the KIR disparity between donor and recipient. Our phase I/II clinical trial presents a dose-escalation design (3+3). The treatment cohorts are divided into cohort 1 (up to 2x10 7 cells/kg), cohort 2 (2-5x10 7 cells/kg) and cohort 3 (5-10x10 7 cells/kg). We have monitored infections reactivation, as well as, chimerism and engraftment after transplantation. In Allo-NK group, the KIR clone that provides alloreactivity in the NK cell was also tracked. The phenotypic profile and functional capacity of NK cells present in the patient up to 360 days after transplantation have also been analyzed. Results: Nine patients (4 in Allo-NK and 5 in IL-15NK) were included in cohort 1, 7 patients (4 in Allo-NK and 3 in IL-15NK) in cohort 2 and 2 patients (1 in Allo-NK and 1 in IL-15NK) in cohort 3. We were unable to complete the dose escalation design initially proposed due to the high weight of some patients and the unavailability of ex vivo expanded NK cells. In IL15-NK group patients presented a higher prevalence of B-ALL (p=0.018) and had received a previous transplant (p=0.082). NK cell infusions of IL15-NK group showed higher expression of CD25 and CD69 receptors and higher functional capacity. In the Allo-NK group, the most prevalent KIR-reactive clone was KIR2DL1 (55.6%). We also observed a tendency for KIR2DL1 alloreactive clone to increase from 30 (8,18%) to 360 (25,63%) days after transplantation. Regarding clinical outcomes in 2 study arms, the incidence of severe (Grades III-IV) acute GvHD was 22.2% and severe chronic GvHD was only observed in 1 (5.6%) patient (Table 1). The incidence any infection or endothelial vascular complications were 72% and 33% respectively. No statistical differences were observed in GvHD, infections and endothelial vascular complications. We found 2 relapses, 1 in each study arm (11.1%). Five patients died, 1 (5.6%) because of disease progression and 4 (22.2%) because transplant related complications (TRM) (Table 1). Dividing patients into the 3 dose-escalation cohorts, we found no significant differences between cohorts in the primary clinical outcomes analysed. One-years overall survival (OS) and disease-free survival (DFS) was 72.22% (CI95% 51.93-100) and GvHD-free/relapse-free survival (GRSF) was 64.1% (CI95% 44.62-92.1), finding no significant differences between either 2 study arms or the 3 dose-escalation cohorts. Regarding the analysis of the NK phenotype, we observed a tendency to increase the expression of CD16 and CD57 receptors between 30 to 360 days after transplantation in both groups. Conclusions: Two study arms shows similar data respect to clinical outcome. Patients infused with IL-15-stimulated NK cells showed similar toxicity to the alloreactive NK group. According to dose escalation, we observed no association between increased toxicity and increased number of infused NK cells. We were unfortunately unable to complete cohort 3 because of the cells/kg ratio in some patients.

Risk factors for severe SARS-Cov-2 infection course are poorly described in children following hematopoietic cell transplantation (HCT). In this international study, we analyzed factors associated with a severe course (intensive care unit (ICU) admission and/or mortality) in post-HCT children. Eighty-nine children (58% male; median age 9 years (min-max 1-18)) who received an allogeneic (85; 96%) or an autologous (4; 4%) HCT were reported from 28 centers (18 countries). Median time from HCT to SARS-Cov-2 infection was 7 months (min-max 0-181). The most common clinical manifestations included fever (37; 42%) and cough (26; 29%); 37 (42%) were asymptomatic. Nine (10%) children following allo-HCT required ICU care. Seven children (8%) following allo-HCT, died at a median of 22 days after SARS-Cov-2 diagnosis. In a univariate analysis, the probability of a severe disease course was higher in allo-HCT children with chronic GVHD, non-malignant disease, immune suppressive treatment (specifically, mycophenolate), moderate immunodeficiency score, low Lansky score, fever, cough, coinfection, pulmonary radiological findings, and high C-reactive protein. In conclusion, SARS-Cov-2 infection in children following HCT was frequently asymptomatic. Despite this, 10% needed ICU admission and 8% died in our cohort. Certain HCT, underlying disease, and SARS-Cov-2 related factors were associated with a severe disease course.

BACKGROUND AND OBJECTIVES:Bone marrow (BM) harvesting is one of the essential sources of stem cells for haematopoietic stem cell transplantation. In 2019, commercial BM collection kits became unavailable in Europe. Consequently, we created an in-house BM collection kit as an alternative. MATERIALS AND METHODS:We compared two groups of BM collections. The first collections were taken using an in-house kit from June 2022 through February 2023 and the second with a commercial kit from February 2021 through May 2022. These all took place at seven collection centres (CC). We analysed the harvest quality (cell blood count, CD34+ cells, viability, potency and sterility), the incidents occurring with each kit and the time to neutrophil and platelet engraftment in recipients. RESULTS:A total of 23 donors underwent BM harvesting with the in-house kit and 23 with the commercial one. Both cohorts were comparable regarding donor characteristics, CC and time to procedure. No statistical differences were found in harvest quality between the in-house and commercial kits. A new transfusion set was required in three BM harvests (13%) with the in-house kit because of filter clogging. The median time to neutrophil and platelet engraftment was 21 days for both cohorts and 29 days (in-house) and 33 days (commercial), p = 0.284, respectively. CONCLUSION:The in-house BM collection kit offers a real approach to solve the diminished supply of commercial kits. A higher risk of filter clogging was observed compared with commercial kits due to the lack of 850 and 500 μm filters.

Omidubicel is an umbilical cord blood (UCB)-derived ex vivo-expanded cellular therapy product that has dem-onstrated faster engraftment and fewer infections compared with unmanipulated UCB in allogeneic hematopoietic cell transplantation. Although the early benefits of omidubicel have been established, long-term outcomes remain unknown. We report on a planned pooled analysis of 5 multicenter clinical trials including 105 patients with hematologic malignancies or sickle cell hemoglobinopathy who underwent omidubicel transplantation at 26 academic transplantation centers worldwide. With a median follow-up of 22 months (range, .3 to 122 months), the 3-year estimated overall survival and disease-free survival were 62.7% and 56.4%, respectively. With up to 10 years of follow-up, omidubicel showed durable trilineage hematopoiesis. Serial quantitative assessments of CD3(+), CD4(+), CD8(+), CD19(+), CD116(+)CD56(+), and CD123(+) immune subsets revealed median counts remaining within normal ranges through up to 8 years of follow-up. Secondary graft failure occurred in 5 patients (5%) in the first year, with no late cases reported. One case of donor-derived myeloid neoplasm was reported at 40 months post-transplantation. This was also observed in a control arm patient who received only unmanipulated UCB. Overall, omidubicel demonstrated stable trilineage hematopoiesis, immune competence, and graft durability in extended follow-up. (c) 2023 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Neurologic complications following stem cell transplantation are of utmost importance owing to their high morbimortality. Although many studies have been performed in the adult population, reports in children are scarce. Our objective was to determine the most common neurologic complications in a pediatric population and to analyze possible risk factors for their development. We performed an exploratory retrospective study of neurologic complications in pediatric patients who had allogeneic stem cell transplantation over the last 18 years. We identified 66 neurologic complications in 178 allogeneic stem cell transplantations. The most frequent neurologic complications were those involving the peripheral nervous system and those related to drug toxicity. Survival decreased significantly in the presence of neurologic complications. Multivariate logistic regression analysis showed that independent risk factors for developing neurologic complications were development of chronic extensive graft-vs-host disease requiring treatment, cytomegalovirus reactivation, and central nervous system radiation. Prompt diagnosis and preemptive treatment, if possible, are necessary to avoid long-term sequelae or mortality.

Cytotoxic T-lymphocyte antigen-4 (CTLA-4) haploinsufficiency is a T-cell hyperactivation disorder that can manifest with both immunodeficiency and immune dysregulation. Approximately one-third of patients may present mild symptoms and remain stable under supportive care. The remaining patients may develop severe multiorgan autoimmunity requiring lifelong immunosuppressive treatment. Hematopoietic stem cell transplantation (HSCT) is potentially curable for patients with treatment-resistant immune dysregulation. Nevertheless, little experience is reported regarding the management of complications post-HSCT. We present case 1 (CTLA-4 haploinsufficiency) and case 2 (CTLA-4 insufficiency-like phenotype) manifesting with severe autoimmunity including cytopenia and involvement of the central nervous system (CNS), lung, and gut and variable impairment of humoral responses. Both patients underwent HSCT for which the main complications were persistent mixed chimerism, infections, and immune-mediated complications [graft-versus-host disease (GVHD) and nodular lung disease]. Detailed management and outcomes of therapeutic interventions post-HSCT are discussed. Concretely, post-HSCT abatacept and human leukocyte antigen (HLA)-matched sibling donor lymphocyte infusions may be used to increase T-cell donor chimerism with the aim of correcting the immune phenotype of CTLA-4 haploinsufficiency.

La hipogammaglobulinemia en los primeros meses postrasplante de progenitores hematopoyéticos (TPH) es común en pacientes pediátricos. Durante esta fase se debe administrar tratamiento sustitutivo con inmunoglobulina humana por vía parenteral para la prevención de infecciones. En algunos casos, esta hipogammaglobulinemia persiste en el tiempo, lo que obliga a prolongar el tratamiento cuando el paciente ya no suele ser portador de una vía central, por lo que son candidatos ideales para el tratamiento de reemplazo por vía subcutánea. Existe escasa bibliografía publicada que describa el uso de esta vía en pacientes pediátricos sometidos a TPH; sin embargo, está ampliamente descrita y con muy buenos resultados en el tratamiento de reemplazo en los niños con inmunodeficiencias primarias. Se realiza un estudio observacional, descriptivo y longitudinal de carácter retrospectivo. Durante los años 2008-2019 se evalúan a todos los pacientes pediátricos sometidos a TPH en nuestro centro que presentan una hipogammaglobulinemia crónica persistente (superior a un año). Se evalúa la fase de tratamiento con inmunoglobulina intravenosa (Privigen®) y los primeros 4 años de tratamiento con inmunoglobulina subcutánea (Hizentra®) mediante un cuestionario. Durante los años 2008-2019 se han realizado en nuestro centro 175 trasplantes de precursores hematopoyéticos, de los cuáles 143 (82%) superaron los 3 meses postrasplante. De estos, 3 (2%) pacientes presentaron una hipogammaglobulinemia persistente. Los 3 comparten factores descritos en la bibliografía involucrados en la reconstitución inmune. Mediante el cuestionario se observa que el cambio de gammaglobulina intravenosa a subcutánea ha supuesto una gran mejoría en la calidad de vida de los pacientes. El origen de la hipogammaglobulinemia crónica de nuestros pacientes presenta diferentes factores, y no se puede atribuir a una sola causa. Debido al limitado número de pacientes no es posible establecer conclusiones a nivel poblacional. Hemos podido observar que el tratamiento de reemplazo con Hizentra® al 20% ha sido igual de eficaz que la vía intravenosa, sin evidenciarse un aumento en las infecciones bacterianas. Además, ha supuesto una mejoría de la calidad de vida y mayor comodidad expresada por los propios pacientes. Hypogammaglobulinemia in the first months after allogeneic hematopoietic stem cell transplantation (HSCT) is common in pediatric patients. During this phase, replacement therapy with human immunoglobulin must be administered parenterally to prevent infections. In some cases, this hypogammaglobulinemia persists over time, which forces further treatment when the patient is usually no longer a carrier of a central line, making them ideal candidates for subcutaneous replacement therapy. There is little published literature describing the use of this method in pediatric patients undergoing HSCT, widely described in replacement treatment in children with primary immunodeficiencies with very good results. An observational, descriptive, longitudinal and retrospective study is carried out. During the years 2008–2019, we evaluated all pediatric patients undergoing HSCT in our center with persistent chronic hypogammaglobulinemia (for over a year). The treatment phase with intravenous immunoglobulin (Privigen®) and the first four years of treatment with subcutaneous immunoglobulin (Hizentra®) are evaluated using a questionnaire. During the years 2008-2019, 175 patients underwent HSCT, 143 (82%) of whom exceeded three months after transplantation. 3 (2%) of them had persistent hypogammaglobulinemia. All three share factors described in the literature involved in immune reconstitution. After analyzing the questionnaire, it is observed that switching from intravenous to subcutaneous gammaglobulin has involved a great improvement in their quality of life. The origin of chronic hypogammaglobulinemia in our patients shows different factors and cannot be attributed to a single cause. Due to the limited number of patients no conclusions can be drawn at the population level. We have been able to observe that replacement treatment with Hizentra® 20% has been as effective as the intravenous administration without evidence of an increase in bacterial infections. Furthermore, it has also led to an improvement in quality of life and increased comfort, as the patients themselves have stated.

Background: Hematopoietic stem cell transplantation (HSCT) represents a curative treatment for patients with severe combined immunodeficiency (SCID), a group of monogenic immune disorders with an otherwise fatal outcome. Objective: We performed a comprehensive multicenter analysis of genotype-specific HSCT outcome, including detailed analysis of immune reconstitution (IR) and the predictive value for clinical outcome. Methods: HSCT outcome was studied in 338 patients with genetically confirmed SCID who underwent transplantation in 2006-2014 and who were registered in the SCETIDE registry. In a representative subgroup of 152 patients, data on IR and longterm clinical outcome were analyzed. Results: Two-year OS was similar with matched family and unrelated donors and better than mismatched donor HSCT (P <.001). The 2-year event-free survival (EFS) was similar in matched and mismatched unrelated donor and less favorable in mismatched related donor (MMRD) HSCT (P <.001). Genetic subgroups did not differ in 2-year OS (P = .1) and EFS (P = .073). In multivariate analysis, pretransplantation infections and use of MMRDs were associated with less favorable OS and EFS. With a median follow-up of 6.2 years (range, 2.0-11.8 years), 73 of 152 patients in the IR cohort were alive and well without Ig dependency. IL-2 receptor gamma chain/Janus kinase 3/IL-7 receptor-deficient SCID, myeloablative conditioning, matched donor HSCT, and naive CD4 T lymphocytes >0.5 3 10(-3)/mL at 11 year were identified as independent predictors of favorable clinical and immunologic outcome. Conclusion: Recent advances in HSCT in SCID patients have resulted in improved OS and EFS in all genotypes and donor types. To achieve a favorable long-term outcome, treatment strategies should aim for optimal naive CD4 T lymphocyte regeneration.