Phase II Study of Allogeneic Hematopoietic Stem Cell Transplantation for Children with High-Risk Neuroblastoma Using a Reduced-Intensity Conditioning Regimen: Results from the AIEOP Trial.

Despite aggressive multimodal treatment, the outcomes of pediatric patients with high-risk (HR) neuroblastoma (NB) remain poor. The rationale for allogeneic hematopoietic stem cell transplantation (allo-HCT) to treat NB was based on the possible graft-versus-tumor effect; however, toxicity limits its efficacy. We sought to prospectively assess the feasibility and efficacy of allo-HCT using a reduced-intensity conditioning regimen in pediatric patients with HR NB in a multicenter phase II trial. Primary endpoints were the rate of neutrophil and platelet engraftment, 5-year transplantation-related mortality (TRM), and disease-free survival (DFS). Secondary endpoint measures included the incidence of acute graft-versus-host disease (aGVHD) and chronic GVHD. Fifty-one patients were enrolled in the study. The 5-year cumulative incidence (CuI) of TRM was 29.4 ± 6.4%, and that of DFS was 11.8 ± 4.5%. Patients undergoing allo-HCT within 1 year of diagnosis or with bone marrow as their stem cell source had a higher DFS probability. The CuI of neutrophil engraftment, platelet engraftment, and grade II-IV aGVHD was 97.9 ± 2.1%, 93.8 ± 3.5%, and 47.1 ± 7.0%, respectively. The development of new therapeutic strategies could further improve disease control.

Long-term and real-world safety and efficacy of retroviral gene therapy for adenosine deaminase deficiency.

Adenosine deaminase (ADA) deficiency leads to severe combined immunodeficiency (SCID). Previous clinical trials showed that autologous CD34+ cell gene therapy (GT) following busulfan reduced-intensity conditioning is a promising therapeutic approach for ADA-SCID, but long-term data are warranted. Here we report an analysis on long-term safety and efficacy data of 43 patients with ADA-SCID who received retroviral ex vivo bone marrow-derived hematopoietic stem cell GT. Twenty-two individuals (median follow-up 15.4 years) were treated in the context of clinical development or named patient program. Nineteen patients were treated post-marketing authorization (median follow-up 3.2 years), and two additional patients received mobilized peripheral blood CD34+ cell GT. At data cutoff, all 43 patients were alive, with a median follow-up of 5.0 years (interquartile range 2.4-15.4) and 2 years intervention-free survival (no need for long-term enzyme replacement therapy or allogeneic hematopoietic stem cell transplantation) of 88% (95% confidence interval 78.7-98.4%). Most adverse events/reactions were related to disease background, busulfan conditioning or immune reconstitution; the safety profile of the real world experience was in line with premarketing cohort. One patient from the named patient program developed a T cell leukemia related to treatment 4.7 years after GT and is currently in remission. Long-term persistence of multilineage gene-corrected cells, metabolic detoxification, immune reconstitution and decreased infection rates were observed. Estimated mixed-effects models showed that higher dose of CD34+ cells infused and younger age at GT affected positively the plateau of CD3+ transduced cells, lymphocytes and CD4+ CD45RA+ naive T cells, whereas the cell dose positively influenced the final plateau of CD15+ transduced cells. These long-term data suggest that the risk-benefit of GT in ADA remains favorable and warrant for continuing long-term safety monitoring. Clinical trial registration: NCT00598481 , NCT03478670 .

Profile of 208 patients with inborn errors of immunity at a tertiary care center in South India.

Primary immune deficiencies or inborn errors of immunity (IEI) are a heterogeneous group of disorders that predispose affected individuals to infections, allergy, autoimmunity, autoinflammation and malignancies. IEIs are increasingly being recognized in the Indian subcontinent. Two hundred and eight patients diagnosed with an IEI during February 2017 to November 2021 at a tertiary care center in South India were included in the study. The clinical features, laboratory findings including microbiologic and genetic data, and treatment and outcome details were analyzed. The diagnosis of IEI was confirmed in a total of 208 patients (198 kindreds) based on relevant immunological tests and/or genetic tests. The male-to-female ratio was 1.8:1. Of the 208 patients, 72 (34.6%) were < 1 yr, 112 (53.8%) were 1-18 years, and 24 (11.5%) were above 18 years. The most common IEI in our cohort was SCID (17.7%) followed by CGD (12.9%) and CVID (9.1%). We also had a significant proportion of patients with DOCK8 deficiency (7.2%), LAD (6.2%) and six patients (2.8%) with autoinflammatory diseases. Autoimmunity was noted in forty-six (22%) patients. Molecular testing was performed in 152 patients by exome sequencing on the NGS platform, and a genetic variant was reported in 132 cases. Twenty-nine children underwent 34 HSCT, and 135 patients remain on supportive therapy such as immunoglobulin replacement and/or antimicrobial prophylaxis. Fifty-nine (28.3%) patients died during the study period, and infections were the predominant cause of mortality. Seven families underwent prenatal testing in the subsequent pregnancy. We describe the profile of 208 patients with IEI, and to the best of our knowledge, this represents the largest data on IEI from the Indian subcontinent reported so far.

Clinical and transcriptomic characteristics of a novel SMARCD2 mutation that disrupts neutrophil maturation and function.

We report a novel case of SMARCD2 (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily D, member 2) mutation successfully treated with hematopoietic stem cell transplantation. The female patient presented delayed cord separation, chronic diarrhea, skin abscesses, skeletal dysmorphisms, and neutropenia with specific granule deficiency. Analysis of the transcriptomic profile of peripheral blood sorted mature and immature SMARCD2 neutrophils showed defective maturation process that associated with altered expression of genes related to specific, azurophilic, and gelatinase granules, such as LTF, CRISP3, PTX3, and CHI3L1. These abnormalities account for the prevalence of immature neutrophils in the peripheral blood, impaired function, and deregulated inflammatory responses.

How to remove a tunneled and cuffed central venous catheter quickly and safely? A little trick useful in children.

BACKGROUND: The aim of this study was to present our experience with a use of own variation of the traditional technique for tunneled and cuffed catheters removal. METHODS: From July 2021 to March 2023, 110 tunneled cuffed centrally inserted central catheters (CICCs) were removed at the Vascular Access Unit of ASST Spedali Civili of Brescia using our particular technique; pediatric patients were 15 admitted to "Children Hospital" of Brescia. The catheter is cut with its adhesions above the cuff and then pulled out. The cuff is then removed with all adhesions attached. RESULTS: Each procedure was successfully performed to the end with local anesthesia, also in younger children. The maneuver was very short and well tolerated. No related complications were observed. The maneuver has always been considered easy even by less experienced surgeons. The scars were aesthetically good and well accepted by the patients. CONCLUSIONS: The technique described has the advantage of not requiring the careful lysis of the adherence from the cuff. If the procedure is quick it can be performed without general anesthesia and without significant psychological trauma also in less compliant children. The skin cut very short leaves an almost invisible scar. It is another notable advantage especially for young girls.

Hemophagocytic inflammatory syndrome in ADA-SCID: report of two cases and literature review.

Hemophagocytic inflammatory syndrome (HIS) is a rare form of secondary hemophagocytic lymphohistiocytosis caused by an impaired equilibrium between natural killer and cytotoxic T-cell activity, evolving in hypercytokinemia and multiorgan failure. In the context of inborn errors of immunity, HIS occurrence has been reported in severe combined immunodeficiency (SCID) patients, including two cases of adenosine deaminase deficient-SCID (ADA-SCID). Here we describe two additional pediatric cases of ADA-SCID patients who developed HIS. In the first case, HIS was triggered by infectious complications while the patient was on enzyme replacement therapy; the patient was treated with high-dose corticosteroids and intravenous immunoglobulins with HIS remission. However, the patient required HLA-identical sibling donor hematopoietic stem cell transplantation (HSCT) for a definitive cure of ADA-SCID, without HIS relapse up to 13 years after HSCT. The second patient presented HIS 2 years after hematopoietic stem cell gene therapy (GT), secondarily to Varicella-Zoster vaccination and despite CD4+ and CD8+ lymphocytes' reconstitution in line with other ADA SCID patients treated with GT. The child responded to trilinear immunosuppressive therapy (corticosteroids, Cyclosporine A, Anakinra). We observed the persistence of gene-corrected cells up to 5 years post-GT, without HIS relapse. These new cases of children with HIS, together with those reported in the literature, support the hypothesis that a major dysregulation in the immune system can occur in ADA-SCID patients. Our cases show that early identification of the disease is imperative and that a variable degree of immunosuppression could be an effective treatment while allogeneic HSCT is required only in cases of refractoriness. A deeper knowledge of immunologic patterns contributing to HIS pathogenesis in ADA-SCID patients is desirable, to identify new targeted treatments and ensure patients' long-term recovery.

GAU-PED study for early diagnosis of Gaucher disease in children with splenomegaly and cytopenia.

BACKGROUND: Gaucher disease (GD) diagnosis can be delayed due to non-specific symptoms and lack of awareness, leading to unnecessary procedures and irreversible complications. GAU-PED study aims to assess GD prevalence in a high-risk pediatric population and the presence, if any, of novel clinical or biochemical markers associated with GD. MATERIALS AND METHODS: DBS samples were collected and tested for ß-glucocerebrosidase enzyme activity for 154 patients selected through the algorithm proposed by Di Rocco et al. Patients showing ß-glucocerebrosidase activity below normal values were recalled to confirm the enzyme deficiency with the gold standard essay on cellular homogenate. Patients tested positive at the gold standard analysis were evaluated through GBA1 gene sequencing. RESULTS: 14 out of 154 patients were diagnosed with GD, with a prevalence of 9.09% (5.06-14.78%, CI 95%). Hepatomegaly, thrombocytopenia, anemia, growth delay/deceleration, elevated serum ferritin, elevated Lyso-Gb1 and chitotriosidase were significantly associated with GD. CONCLUSIONS: GD prevalence in a pediatric population at high-risk appeared to be higher compared to high-risk adults. Lyso-Gb1 was associated with GD diagnosis. The algorithm proposed by Di Rocco et al. can potentially improve the diagnostic accuracy of pediatric GD, allowing the prompt start of therapy, aiming to reduce irreversible complications.

Pseudo-tunneling procedure: an advantageous and safe technique for brachial catheters in younger children.

BACKGROUND: The aim of this study is to present our experience with the use of a particular tunneling technique called pseudo-tunnelling, during insertion of peripherally inserted central catheters (PICCs) and Midlines in younger patients. The children's brachial veins at the middle third of the arm are usually too small for cannulation. So the veins in the axilla are the best option for implantation of a four or five French catheter. A pseudo-tunneling procedure can create an exit site at the middle of the arm without using other procedural sets. METHODS: From January 2014 to August 2022, 60 PICCs and 113 midlines were inserted in children admitted to Children Hospital of Brescia. RESULTS: Every procedure was successfully performed during the first or the second time at latest. The time of procedure was not significantly different from non tunnelized procedures. No insertion related complications were observed. CONCLUSIONS: Our data suggests that pseudo-tunneling is a safe and effective procedure for brachial device implants to avoid central venous catheterization even in pediatric patients.

Dysphagia-related mucositis in children undergoing chemotherapy: The COMEDY pattern.

OBJECTIVES: Children undergoing chemotherapy can experience dysphagia due to non-erosive reflux disease (NERD). Oral mucositis (OM) associated with NERD-dysphagia in children with cancer has recently been defined with the acronym COMEDY (Clenching, Oral Mucositis, closed Eyes, DYsphagia). This study aims to identify the prevalence of the COMEDY pattern among chemotherapy-induced OM. SUBJECTS AND METHODS: Forty-two medical records of children undergoing chemotherapy for haemato-oncologic diseases and presenting OM were reviewed. The following data were collected: age, type of haemato-oncologic disease, presence of dysphagia, type of oral mucosal lesions (i.e. traditional oral mucositis or COMEDY pattern), site of oral lesions, ear-nose-throat (ENT) assessment for the indirect signs of NERD and paediatric neuro-psychiatric (PNP) assessment. RESULTS: Among 42 children with chemotherapy-related OM, 6 patients (14.2%) showed the COMEDY pattern. Besides the characteristic clinical aspect of the oral mucosa, initially classified as grade II OM, these children suffered from NERD-related dysphagia and PNP issues. CONCLUSION: A COMEDY pattern can occur in a number of cases of chemotherapy-induced OM; recognizing this pattern may improve the effectiveness of treatment.

Adenovirus Infection in Pediatric Hematopoietic Cell Transplantation: A Challenge Still Open for Survival.

Human Adenovirus (HAdV) infection occurs in 14−16% of patients in the early months after pediatric hematopoietic cell transplantation (HCT) and this correlates with a higher risk of developing HAdV disease and overall 6-month mortality. The main risk factors for HAdV infection are T-cell depletion of the graft by ex vivo CD34+ selection or in vivo use of alemtuzumab or anti-thymocyte serum, the development of grade III-IV graft versus host disease (GVHD), the type of donor (unrelated donor, cord blood, haploidentical, or HLA mismatched parent), and severe lymphopenia (<0.2 × 109/L). The prevention of HAdV disease is based on early intervention with antivirals in the asymptomatic patient when the permitted viral load threshold in the blood (≥102−3 copies/mL) and/or in the stool (109 copies/g stool) is exceeded. Cidofovir, a monophosphate nucleotide analog of cytosine, is the primary drug for preemptive therapy, used at 5 mg/kg/week for 2 weeks followed by 3−5 mg/kg every 2 weeks. The alternative schedule is 1 mg/kg every other day (three times/week). Enhancing virus-specific T-cell immunity in the first months post-HCT by donor-derived or third-party-derived virus-specific T cells represents an innovative and promising way of intervention, applicable both in prevention and therapeutic settings.

Pathogenesis of Autoimmune Cytopenias in Inborn Errors of Immunity Revealing Novel Therapeutic Targets.

Autoimmune diseases are usually associated with environmental triggers and genetic predisposition. However, a few number of autoimmune diseases has a monogenic cause, mostly in children. These diseases may be the expression, isolated or associated with other symptoms, of an underlying inborn error of immunity (IEI). Autoimmune cytopenias (AICs), including immune thrombocytopenic purpura (ITP), autoimmune hemolytic anemia (AIHA), autoimmune neutropenia (AN), and Evans' syndrome (ES) are common presentations of immunological diseases in the pediatric age, with at least 65% of cases of ES genetically determined. Autoimmune cytopenias in IEI have often a more severe, chronic, and relapsing course. Treatment refractoriness also characterizes autoimmune cytopenia with a monogenic cause, such as IEI. The mechanisms underlying autoimmune cytopenias in IEI include cellular or humoral autoimmunity, immune dysregulation in cases of hemophagocytosis or lymphoproliferation with or without splenic sequestration, bone marrow failure, myelodysplasia, or secondary myelosuppression. Genetic characterization of autoimmune cytopenias is of fundamental importance as an early diagnosis improves the outcome and allows the setting up of a targeted therapy, such as CTLA-4 IgG fusion protein (Abatacept), small molecule inhibitors (JAK-inhibitors), or gene therapy. Currently, gene therapy represents one of the most attractive targeted therapeutic approaches to treat selected inborn errors of immunity. Even in the absence of specific targeted therapies, however, whole exome genetic testing (WES) for children with chronic multilineage cytopenias should be considered as an early diagnostic tool for disease diagnosis and genetic counseling.

Hematopoietic stem cell transplantation for adolescents and adults with inborn errors of immunity: an EBMT IEWP study.

Allogeneic hematopoietic stem cell transplantation (HSCT) is the gold standard curative therapy for infants and children with many inborn errors of immunity (IEI), but adolescents and adults with IEI are rarely referred for transplant. Lack of published HSCT outcome data outside small, single-center studies and perceived high risk of transplant-related mortality have delayed the adoption of HSCT for IEI patients presenting or developing significant organ damage later in life. This large retrospective, multicenter HSCT outcome study reports on 329 IEI patients (age range, 15-62.5 years at HSCT). Patients underwent first HSCT between 2000 and 2019. Primary endpoints were overall survival (OS) and event-free survival (EFS). We also evaluated the influence of IEI-subgroup and IEI-specific risk factors at HSCT, including infections, bronchiectasis, colitis, malignancy, inflammatory lung disease, splenectomy, hepatic dysfunction, and systemic immunosuppression. At a median follow-up of 44.3 months, the estimated OS at 1 and 5 years post-HSCT for all patients was 78% and 71%, and EFS was 65% and 62%, respectively, with low rates of severe acute (8%) or extensive chronic (7%) graft-versus-host disease. On univariate analysis, OS and EFS were inferior in patients with primary antibody deficiency, bronchiectasis, prior splenectomy, hepatic comorbidity, and higher hematopoietic cell transplant comorbidity index scores. On multivariable analysis, EFS was inferior in those with a higher number of IEI-associated complications. Neither age nor donor had a significant effect on OS or EFS. We have identified age-independent risk factors for adverse outcome, providing much needed evidence to identify which patients are most likely to benefit from HSCT.

Hematopoietic stem cell transplantation for Wiskott-Aldrich syndrome: an EBMT Inborn Errors Working Party analysis.

Allogeneic hematopoietic stem cell transplantation (HSCT) is a potentially curative treatment for patients affected by Wiskott-Aldrich syndrome (WAS). Reported HSCT outcomes have improved over time with respect to overall survival, but some studies have identified older age and HSCT from alternative donors as risk factors predicting poorer outcome. We analyzed 197 patients undergoing transplant at European Society for Blood and Marrow Transplantation centers between 2006 and 2017 who received conditioning as recommended by the Inborn Errors Working Party (IEWP): either busulfan (n = 103) or treosulfan (n = 94) combined with fludarabine ± thiotepa. After a median follow-up post-HSCT of 44.9 months, 176 patients were alive, resulting in a 3-year overall survival of 88.7% and chronic graft-versus-host disease (GVHD)-free survival (events include death, graft failure, and severe chronic GVHD) of 81.7%. Overall survival and chronic GVHD-free survival were not significantly affected by conditioning regimen (busulfan- vs treosulfan-based), donor type (matched sibling donor/matched family donor vs matched unrelated donor/mismatched unrelated donor vs mismatched family donor), or period of HSCT (2006-2013 vs 2014-2017). Patients aged <5 years at HSCT had a significantly better overall survival. The overall cumulative incidences of grade III to IV acute GVHD and extensive/moderate/severe chronic GVHD were 6.6% and 2.1%, respectively. Patients receiving treosulfan-based conditioning had a higher incidence of graft failure and mixed donor chimerism and more frequently underwent secondary procedures (second HSCT, unconditioned stem cell boost, donor lymphocyte infusion, or splenectomy). In summary, HSCT for WAS with conditioning regimens currently recommended by IEWP results in excellent survival and low rates of GVHD, regardless of donor or stem cell source, but age ≥5 years remains a risk factor for overall survival.

When a Nontuberculous Mycobacterial Infection Reveals an Error of Immunity: A Single Center's Experience.

We present an algorithm that may be applied in case of a diagnosis of pediatric nontuberculous mycobacterial disease to identify the patients who may require an immunologic assessment to discover a possible underlying immune system defect predisposing to their nontuberculous mycobacterial infections.

Omenn Syndrome due to RAG1 Mutation Presenting With Nonimmune Hydrops Fetalis in Two Siblings.

Omenn syndrome (OS) is a rare variant of severe combined immunodeficiency characterized by susceptibility to severe opportunistic infections and peculiar manifestations, such as protein-losing erythroderma, alopecia, hepatosplenomegaly, lymphadenopathies, and severe diarrhea. The typical form of the disease is caused by hypomorphic mutation of the recombination-activating genes (RAG1 and RAG2), which are critical in initiating the molecular processes leading to lymphocyte and immunoglobulin receptor formation. Affected patients lack B cells, whereas autoreactive oligoclonal T cells infiltrate the skin, gut, spleen, and liver. In the absence of hematopoietic stem cell transplantation, patients with OS usually succumb early in life because of opportunistic infections. The incidence of OS is estimated to be <1 per 1 000 000; however, the actual frequency is difficult to ascertain. We report 2 siblings affected by OS due to a homozygous frameshift mutation (NM_000448.3:c.519delT, p.E174Sfs*26) in the RAG1 gene presenting with nonimmune hydrops fetalis (NIHF). To the best of our knowledge, this is the first reported association between OS and NIHF. NIHF specifically refers to the presence of ≥2 abnormal fluid collections in the fetus, without red blood cell alloimmunization. A broad spectrum of pathologies is associated with NIHF; however, in ∼20% of the cases, the primary cause remains unclear. Understanding the etiology of NIHF is essential for guiding clinical management, determining prognosis, and informing parents regarding recurrence risk. Our case contributes to expanding the spectrum of OS presentation and highlights the importance of a complete immunologic and genetic workup in otherwise unexplained cases of NIHF.

CD34+ Stem Cell Selection and CD3+ T Cell Add-Back from Matched Unrelated Adult Donors in Children with Primary Immunodeficiencies and Hematological Diseases.

Less than 25% of children who require hematopoietic stem cell transplantation (HSCT) for primary immunodeficiencies (PIDs) or genetic hematological diseases have an HLA-identical sibling. For them, a matched unrelated donor (MUD), although baring a greater risk of graft failure, delayed engraftment and immune reconstitution, and severe graft-versus-host disease (GvHD), represents a valid alternative. The stem cell source is also important, as unprocessed peripheral blood stem cells (PBSCs) contain 5 to 10 times more T cells than bone marrow (BM)-derived grafts, a major risk especially for small children with PID. A CD34+ positive selection can mitigate HLA compatibility issues, but the resulting CD3+ T cell depletion hampers engraftment and facilitates infections. To mitigate those problems, we decided to add back a certain number of T cells (30 × 106 cells/kg body weight [BW]) to the positive CD34+ selection derived from MUD BM or PBSCs and report the results in terms of time to engraftment and immune reconstitution, GvHD incidence, infections, and survival. Our aim was to show not only the feasibility and clinical efficacy of this addback but also that PBSC-derived CD34+ selected grafts with calibrated T cell addback would be equivalent to BM-derived grafts. We analyzed retrospectively our single-center cohort of 76 children (median age, 1.9 years) affected by PID (61) and hematological diseases (15) who received a total of 79 MUD HSCTs with CD34+ selection and addback of 30 × 106 CD3+ cells/kg BW between 2001 and 2019. We used descriptive and analytic statistics (chi-square, Student's t-test, Mann-Whitney U test, as appropriate) and constructed Kaplan-Meier curves using the log-rank test to compare patients grafted with BM or PBSC-derived inocula. The two groups showed no statistically significant differences in terms of age, sex, HLA-mismatch, or amount of CD3+ cells/kg BW added back to the CD34+ selection. However, the latter being higher in the PBSC group (P = .0001). Overall engraftment rate was 96% (73/76) and occurred faster in the PBSC group than in BM recipients: polymorphonuclear cells, 16 versus 21 days (P = .006); platelets, 15 versus 22 days (P = .001). GvHD incidence was low. No acute GvHD was diagnosed in 24 children, whereas grades I, II, III, and IV occurred in 19, 28, five, and three children, respectively (P not significant). Chronic GvHD was seen in only two children. The CD4+ count at six months after HSCT was higher in PBSC recipients as compared to those receiving BM (184 versus 88 CD4+ cells; P = .003). Overall survival for the whole cohort was 80% at 10 years, with no significant difference between the two stem cell sources (P not significant). Viral infections occurred among five of the PBSC grafted children and 14 in the BM group (P not significant), and no patient suffered from post-transplant lymphoproliferative disorder (PTLD). The results we present show that an addback of 30 × 106 donor CD3+ cells/kg recipient BW to a MUD BM or PBSC-derived CD34+ selection gives promising results in infants and young children undergoing HSCT for PID or hematological diseases. Furthermore, with this manipulation the inherent limits of PBSC-derived grafts can be overcome, allowing both swift engraftment and immune reconstitution without an increase in GvHD, infections, or PTLD.

Childhood cancer in Italy: background, goals, and achievements of the Italian Paediatric Hematology Oncology Association (AIEOP).

This article reviews the primary goals and achievements of the Italian Association for Pediatric Hematology-Oncology (Associazione Italiana Ematologia Oncologia Pediatrica [AIEOP]), a national cooperative group that has been working for children and adolescents with cancer in Italy since 1975.

Allogeneic hematopoietic stem cell transplantation in leukocyte adhesion deficiency type I and III.

Type I and III leukocyte adhesion deficiencies (LADs) are primary immunodeficiency disorders resulting in early death due to infections and additional bleeding tendency in LAD-III. The curative treatment of LAD-I and LAD-III is allogeneic hematopoietic stem cell transplantation (allo-HSCT). In this retrospective multicenter study, data were collected using the European Society for Blood and Marrow Transplantation registry; we analyzed data from 84 LAD patients from 33 centers, all receiving an allo-HSCT from 2007 to 2017. The 3-year overall survival estimate (95% confidence interval [CI]) was 83% (74-92) for the entire cohort: 84% (75-94) and 75% (50-100) for LAD-I and LAD-III, respectively. We observed cumulative incidences (95% CI) of graft failure (GF) at 3 years of 17% (9%-26%) and grade II to IV acute graft-versus-host disease (aGVHD) at 100 days of 24% (15%-34%). The estimate (95% CI) at 3 years for GF- and GVHD-II to IV-free survival as event-free survival (EFS) was 56% (46-69) for the entire cohort; 58% (46-72) and 56% (23-88) for LAD-I and LAD-III, respectively. Grade II to IV acute GVHD was a relevant risk factor for death (hazard ratio 3.6; 95% CI 1.4-9.1; P = .006). Patients' age at transplant ≥13 months, transplantation from a nonsibling donor, and any serological cytomegalovirus mismatch in donor-recipient pairs were significantly associated with severe acute GVHD and inferior EFS. The choice of busulfan- or treosulfan-based conditioning, type of GVHD prophylaxis, and serotherapy did not impact overall survival, EFS, or aGVHD. An intrinsic inflammatory component of LAD may contribute to inflammatory complications during allo-HSCT, thus providing the rationale for considering anti-inflammatory therapy pretreatment.