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Hematopoietic stem cell transplantation and gene therapy are the only curative therapies for severe combined immunodeficiency (SCID). In patients lacking a matched donor, TCRαβ/CD19-depleted haploidentical family donor transplant (TCRαβ-HaploSCT) is a promising strategy. Conditioned transplant in SCID correlates to better myeloid chimerism and reduced immunoglobulin dependency. We studied transplant outcome in SCID infants according to donor type, specifically TCRαβ-HaploSCT, and conditioning, through retrospective cohort analysis of 52 consecutive infants with SCID transplanted between 2013 and 2020. Median age at transplant was 5.1 months (range, 0.8–16.6). Donors were TCRαβ-HaploSCT (n = 16, 31.4%), matched family donor (MFD, n = 15, 29.4%), matched unrelated donor (MUD, n = 9, 17.6%), and matched unrelated cord blood (CB, n = 11, 21.6%). Forty-one (80%) received fludarabine/treosulfan-based conditioning, 3 (6%) had alemtuzumab only, and 7 (14%) received unconditioned infusions. For conditioned transplants (n = 41), 3-year overall survival was 91% (95% confidence interval, 52–99%) for TCRαβ-HaploSCT, 80% (41–98%) for MFD, 87% (36–98%) for MUD, and 89% (43–98%) for CB (p = 0.89). Cumulative incidence of grade II–IV acute graft-versus-host disease was 11% (2–79%) after TCRαβ-HaploSCT, 0 after MFD, 29% (7–100%) after MUD, and 11% (2–79%) after CB (p = 0.10). 9/10 patients who received alemtuzumab-only or unconditioned transplants survived. Myeloid chimerism was higher following conditioning (median 47%, range 0–100%) versus unconditioned transplant (median 3%, 0–9%) (p n = 29/36, 81% vs n = 4/9, 54%) (p

Molecular dissection of inborn errors of immunity can help to elucidate the nonredundant functions of individual genes. We studied 3 children with an immune dysregulation syndrome of susceptibility to infection, lymphadenopathy, hepatosplenomegaly, developmental delay, autoimmunity, and lymphoma of B-cell (n = 2) or T-cell (n = 1) origin. All 3 showed early autologous T-cell reconstitution following allogeneic hematopoietic stem cell transplantation. By whole-exome sequencing, we identified rare homozygous germline missense or nonsense variants in a known epigenetic regulator of gene expression: ten-eleven translocation methylcytosine dioxygenase 2 (TET2). Mutated TET2 protein was absent or enzymatically defective for 5-hydroxymethylating activity, resulting in whole-blood DNA hypermethylation. Circulating T cells showed an abnormal immunophenotype including expanded double-negative, but depleted follicular helper, T-cell compartments and impaired Fas-dependent apoptosis in 2 of 3 patients. Moreover, TET2-deficient B cells showed defective class-switch recombination. The hematopoietic potential of patient-derived induced pluripotent stem cells was skewed toward the myeloid lineage. These are the first reported cases of autosomal-recessive germline TET2 deficiency in humans, causing clinically significant immunodeficiency and an autoimmune lymphoproliferative syndrome with marked predisposition to lymphoma. This disease phenotype demonstrates the broad role of TET2 within the human immune system.

Background Post hematopoietic cell transplantation (HCT) autoimmune cytopenia (AIC) is a potentially life-threatening complication, but studies focusing on large cohorts of patients transplanted for primary immunodeficiency are lacking. Objectives This study sought to determine the incidence, risk factors, and outcomes of post-HCT AIC and B-lymphocyte function following rituximab. Methods We retrospectively studied 502 children with primary immunodeficiency who were transplanted at our center between 1987 and 2018. Results Thirty-six patients (9%) developed post-HCT AIC, with a median onset of 6.5 months post-HCT. On univariate analysis, pre-HCT AIC, mismatched donor, alemtuzumab, anti-thymocyte antiglobulin, and acute and chronic graft versus host disease were significantly associated with post-HCT AIC. After multivariate analysis, alemtuzumab (subdistribution hazard ratio, 9.0; 95% CI, 1.50-54.0; P = .02) was independently associated with post-HCT AIC. Corticosteroid and high-dose intravenous immunoglobulin achieved remission in 50% (n = 18), additional rituximab led to remission in 25% (n = 9), and the remaining 25% were treated with a combination of various modalities including sirolimus (n = 5), bortezomib (n = 3), mycophenolate mofetil (n = 2), splenectomy (n = 2), and second HCT (n = 3). The mortality of post-HCT AIC reduced from 25% (4 of 16) prior to 2011 to 5% (1 of 20) after 2011. The median follow-up of 5.8 years (range, 0.4 to 29.1 years) showed that 26 of 30 survivors (87%) were in complete remission, and 4 were in remission with ongoing sirolimus and low-dose steroids. Of the 17 who received rituximab, 7 had B-lymphocyte recovery, 5 had persistent low B-lymphocyte count and remained on intravenous immunoglobulin replacement, 2 had second HCT, and 3 died. Conclusions The frequency of post HCT AIC in our cohort was 9%, and the most significant risk factors for its occurrence were the presence of graft versus host disease and the use of alemtuzumab.

Hematopoietic stem cell transplantation and gene therapy are the only curative therapies for severe combined immunodeficiency (SCID). In patients lacking a matched donor, TCRαβ/CD19-depleted haploidentical family donor transplant (TCRαβ-HaploSCT) is a promising strategy. Conditioned transplant in SCID correlates to better myeloid chimerism and reduced immunoglobulin dependency. We studied transplant outcome in SCID infants according to donor type, specifically TCRαβ-HaploSCT, and conditioning, through retrospective cohort analysis of 52 consecutive infants with SCID transplanted between 2013 and 2020. Median age at transplant was 5.1 months (range, 0.8-16.6). Donors were TCRαβ-HaploSCT (n = 16, 31.4%), matched family donor (MFD, n = 15, 29.4%), matched unrelated donor (MUD, n = 9, 17.6%), and matched unrelated cord blood (CB, n = 11, 21.6%). Forty-one (80%) received fludarabine/treosulfan-based conditioning, 3 (6%) had alemtuzumab only, and 7 (14%) received unconditioned infusions. For conditioned transplants (n = 41), 3-year overall survival was 91% (95% confidence interval, 52-99%) for TCRαβ-HaploSCT, 80% (41-98%) for MFD, 87% (36-98%) for MUD, and 89% (43-98%) for CB (p = 0.89). Cumulative incidence of grade II-IV acute graft-versus-host disease was 11% (2-79%) after TCRαβ-HaploSCT, 0 after MFD, 29% (7-100%) after MUD, and 11% (2-79%) after CB (p = 0.10). 9/10 patients who received alemtuzumab-only or unconditioned transplants survived. Myeloid chimerism was higher following conditioning (median 47%, range 0-100%) versus unconditioned transplant (median 3%, 0-9%) (p 0.001), as was the proportion of immunoglobulin-free long-term survivors (n = 29/36, 81% vs n = 4/9, 54%) (p 0.001). TCRαβ-HaploSCT has comparable outcome to MUD and is a promising alternative donor strategy for infants with SCID lacking MFD. This study confirms that conditioned transplant offers better myeloid chimerism and immunoglobulin freedom in long-term survivors.

Autosomal dominant hyper-IgE syndrome caused by dominant-negative loss-of-function mutations in signal transducer and activator of transcription factor 3 (STAT3) (STAT3-HIES) is a rare primary immunodeficiency with multisystem pathology. The quality of life in patients with STAT3-HIES is determined by not only the progressive, life-limiting pulmonary disease, but also significant skin disease including recurrent infections and abscesses requiring surgery. Our early report indicated that hematopoietic stem cell transplantation might not be effective in patients with STAT3-HIES, although a few subsequent reports have reported successful outcomes. We update on progress of our patient now with over 18 years of follow-up and report on an additional seven cases, all of whom have survived despite demonstrating significant disease-related pathology prior to transplant. We conclude that effective cure of the immunological aspects of the disease and stabilization of even severe lung involvement may be achieved by allogeneic hematopoietic stem cell transplantation. Recurrent skin infections and abscesses may be abolished. Donor TH17 cells may produce comparable levels of IL17A to healthy controls. The future challenge will be to determine which patients should best be offered this treatment and at what point in their disease history.

Background Mismatched stem cell transplantation is associated with a high risk of graft loss, graft-versus-host disease (GvHD), and transplant-related mortality. Alternative graft manipulation strategies have been used over the last 11 years to reduce these risks. Objective We investigated the outcome of using different graft manipulation strategies among children with primary immunodeficiencies. Methods Between 2006 and 2017, 147 patients with primary immunodeficiencies received 155 mismatched grafts: 30 T-cell receptor (TCR) αβ/CD19–depleted grafts, 43 cord blood (CB) grafts (72% with no serotherapy), 17 CD34+ selection with T-cell add-back grafts, and 65 unmanipulated grafts. Results The estimated 8-year survival of the entire cohort was 79%, transplant-related mortality was 21.7%, and the graft failure rate was 6.7%. Posttransplantation viral reactivation, grade II to IV acute graft-versus-host disease (aGvHD), and chronic graft-versus-host disease (cGvHD) complicated 49.6%, 35%, and 15% of transplantations, respectively. Use of TCRαβ/CD19 depletion was associated with a significantly lower incidence of grade II to IV aGvHD (11.5%) and cGvHD (0%), although with a greater incidence of viral reactivation (70%) in comparison with other grafts. T-cell immune reconstitution was robust among CB transplants, although with a high incidence (56.7%) of grade II to IV aGvHD. Stable full donor engraftment was significantly greater at 80% among TCRαβ+/CD19+-depleted and CB transplants versus 40% to 60% among the other groups. Conclusions Rapidly accessible CB and haploidentical grafts are suitable alternatives for patients with no HLA-matched donor. Cord transplantation without serotherapy and TCRαβ+/CD19+-depleted grafts produced comparable survival rates of around 80%, although with a high rate of aGvHD with the former and a high risk of viral reactivation with the latter that need to be addressed.

Genetic subgroups; Immune reconstitution; Pretransplantation infections Subgrupos genéticos; Reconstitución inmune; Infecciones previas al trasplante Subgrups genètics; Reconstitució immune; Infeccions prèvies al trasplantament 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 long-term 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 × 10e3/μL at +1 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.

This study aimed to identify a risk profile for development of transplant-associated thrombotic microangiopathy (TA-TMA) in children undergoing hematopoietic stem cell transplantation (HSCT). Between 2013 and 2016, 439 children underwent 474 HSCTs at 2 supraregional United Kingdom centers. At a median of 153 days post-HSCT, TA-TMA occurred among 25 of 441 evaluable cases (5.6%) with no evidence of center variation. Sex, underlying disease, intensity of the conditioning, total body irradiation–based conditioning, the use of calcineurin inhibitors, venoocclusive disease, and viral reactivation did not influence the development of TA-TMA. Donor type: matched sibling donor/matched family donor vs matched unrelated donor vs mismatched unrelated donor/haplo-HSCT, showed a trend toward the development of TA-TMA in 1.8% vs 6.1% vs 8.3%, respectively. Presence of active comorbidity was associated with an increased risk for TA-TMA; 13% vs 3.7% in the absence of comorbidity. The risk of TA-TMA was threefold higher among patients who received >1 transplant. TA-TMA rates were significantly higher among patients with acute graft-versus-host disease (aGVHD) grades III to IV vs aGVHD grade 0 to II. On multivariate analysis, the presence of active comorbidity, >1 transplant, aGVHD grade III to IV were risk factors for TA-TMA (odds ratio [OR]: 5.1, 5.2, and 26.9; respectively), whereas the use of cyclosporine A/tacrolimus-based GVHD prophylaxis was not a risk factor for TA-TMA (OR: 0.3). Active comorbidity, subsequent transplant, and aGVHD grades III to IV were significant risk factors for TA-TMA. TA-TMA might represent a form of a vascular GVHD, and therefore, continuing control of aGVHD is important to prevent worsening of TA-TMA associated with GVHD.

Cytidine triphosphate (CTP) synthase 1 is responsible for the catalytic conversion of uridine triphosphate (UTP) to CTP in lymphocytes. This reaction is important for the biosynthesis of nucleic acids, playing a key role in lymphocyte function and turnover. Lack of this enzyme due to mutation in CTPS gene is associated with impaired capacity of activated T and B-lymphocytes to proliferate in response to antigen-induced activation. Patients with this mutation all have ancestors from the North West of England and present in the first decade of life with severe acute and chronic herpes virus infections and recurrent infections with encapsulated bacteria. There is a high risk of EBV-driven lymphoma. This is a potentially life-threatening primary immune deficiency (PID) and long-term survival has not been reported. We report on 11 patients with CTPS1 mutations who underwent hematopoietic stem cell transplant (HSCT) at three UK centres (London, Manchester and Newcastle). The molecular diagnosis was made pre-HSCT in six patients and retrospectively in five patients who had undergone HSCT for previously undiagnosed life-threatening PID. All patients had the same homozygous NM_001905.3: c.1692-1G>C mutation (rs145092287) mutation and all the parents were heterozygous carriers. This mutation is known to lead to an abnormal transcript lacking exon 18 and complete lack of protein expression. Six patients had an affected 39 sibling. Patient 1 had 2 affected siblings who died of infection and hemophagocytic lymphohistiocytosis (HLH) in early childhood and patient 2 also had a sibling who died of overwhelming VZV and EBV infections before diagnosis. Pre-transplant features are summarized in Table 1. Systemic viral infections were seen in all patients, with acute and chronic EBV infections in nine patients, four suffering from EBV-driven lymphoproliferative disease (LPD) (two CNS and one lung) and one with EBV-driven HLH. Four patients had severe chickenpox. Five patients presented with chronic diarrhea. Four patients with EBV-driven LPD received rituximab and three EBV-specific cytotoxic T-lymphocytes (CTLs) (two pre-transplant and one post-transplant). The age of the patients at transplant ranged from 15 months to 17 years. The source of stem cells was peripheral blood (PB) in seven patients, bone marrow (BM) in three and cord blood (CB) in one. Eight received matched (10/10) donor stem cells, two had 1/10 mismatches and one received a haploidentical 6/10 transplant from his father as there were no suitable matched donor (Table 2). All but one received conditioning with fludarabine in combination with treosulfan (n=3), melphalan (n=4), treosulfan and thiotepa (n=1, the non-reduced intensity conditioning (RIC) protocol) or low dose busulfan (n=2)3 one received treosulfan and cyclophosphamide. All but one patient received serotherapy with alemtuzumab (n=8) or anti T cell globulin (ATG) (n=2). CD34+ cell dose ranged from 0.4 - 16.1 x 106/kg. Neutrophil engraftment (≥0.5 x 109 51 /L) occurred between day 11- 23 post-transplant. Ten had 100% CD3 donor engraftment and one had 76% in last follow up. Eight patients are alive with post-HSCT follow-up of 8 months to 22 years. All surviving patients have discontinued immunosuppression and six are off immunoglobulin replacement therapy. Patient 4 died 76 days post-HSCT following EBV CNS reactivation leading to obstructive hydrocephalus. She was treated with external ventricular drainage and three doses of 2 x 106 55 EBV-CTLs but died of multi-organ failure 4 56 . Patient 7 developed intractable gut inflammation due to a combination of adenovirus and CMV colitis and chronic graft versus host disease (cGvHD) and died at day +290 despite treatment with ganciclovir and cidofovir for the viral infections and corticosteroids, ciclosporin, tacrolimus and infliximab as anti-inflammatory drugs. Patient 8 developed mild acute skin GvHD post-transplant, but later suffered from intractable chronic skin GvHD (but no gut or liver disease) unresponsive to corticosteroids and extracorporeal photophoresis. Twelve months post-transplantation he developed a tremor and altered mental state progressing to coma and died 15 months post-transplant. Brain biopsy and magnetic resonance (MR) scan performed prior to death were indicative of progressive multifocal leukoencephalopathy (PML), although no JC, BK or astrovirus were isolated from cerebrospinal fluid (CSF) or brain tissue. CTPS1 deficiency is a serious life-limiting immunodeficiency with a high risk of death from VZV and EBV in the first decade of life. Seven (41%) of 17 patients worldwide with CTPS1 deficiency have died, three post and four prior to HSCT (one from fulminant VZV and the other three from fulminant EBV LPD). These deaths were prior to clinical availability of rituximab. However, mild clinical phenotype has previously been described. HSCT can be curative but is not without potential risks and complications. Kucuk et al also reported two siblings with this mutation who had successful transplantation. The current report is the largest series of children with CTPS1 deficiency who have undergone HSCT.The overall survival post-HSCT in this series was 72% which is slightly lower than seen after HSCT for other combined PIDs. Pre-transplantation, extra-nodal EBV-driven LPD of the brain and lung as well as fulminant VZV pneumonitis requiring ventilation in intensive care are major risks. The post-transplantation course can be challenging to even the specialist centres because of re-activation of EBV and other herpes viruses, particularly in the brain and gastrointestinal tract, but also because of the risk of unusually severe skin and gut cGvHD, the latter which may be partly fuelled by ongoing underlying low grade chronic viral infection. Both patients that developed fatal GvHD had transplants from 9/10 matched unrelated donors. Viral reactivation can be observed prior to donor T-lymphocyte engraftment post-transplant and perhaps virus-specific CTLs may be helpful in some of these patients. There is no doubt that HSCT can be curative in this condition and we recommend early transplantation before the onset of end-organ damage and for patients without fully matching family or unrelated donors, the consideration of ex-vivo T-cell depletion strategies.

Publisher's Note: There is a Blood Commentary on this article in this issue.

We previously published results for 70 children who received conditioning with treosulfan and cyclophosphamide (n = 30) or fludarabine (n = 40) before undergoing hematopoietic stem cell transplantation (HSCT) for primary immunodeficiency (PID). Toxicity was lower and T cell chimerism was better in the patients receiving fludarabine, but cohort numbers were relatively small and follow-up was short. Here we report outcomes of 160 children who received homogeneous conditioning with treosulfan, fludarabine, and, in most cases, alemtuzumab (n = 124). The median age at transplantation was 1.36 years (range, .09 to 18.25 years). Donors included 73 matched unrelated, 54 1 to 3 antigen-mismatched unrelated, 12 matched sibling, 17 other matched family, and 4 haploidentical donors. Stem cell source was peripheral blood stem cells (PBSCs) in 70, bone marrow in 49, and cord blood in 41. Median duration of follow-up was 4.3 years (range, .8 to 9.4 years). Overall survival was 83%. No patients had veno-occlusive disease. Seventy-four patients (46%) had acute GVHD, but only 14 (9%) greater than grade II. Four patients underwent successful retransplantation for graft loss or poor immune reconstitution. Another patient experienced graft rejection and died. There was no association between T cell chimerism >95% and stem cell source, but a significant association was seen between myeloid chimerism >95% and use of PBSCs without an increased risk of significant GVHD compared with other sources. All 11 patients with severe combined immunodeficiency diagnosed at birth were alive at up to 8.7 years of follow-up. Long-term studies are needed to determine late gonadotoxic effects, and pharmacokinetic studies are needed to identify whether specific targeting is advantageous. The combination of treosulfan, fludarabine, and alemtuzumab is associated with excellent results in HSCT for PID.

The standard for selecting unrelated umbilical cord blood units for transplantation for non-malignant diseases relies on antigen-level (lower resolution) HLA typing for HLA-A and HLA-B, and allele-level for HLA-DRB1. We aimed to study the effects of allele-level matching at a higher resolution-HLA-A, HLA-B, HLA-C, and HLA-DRB1, which is the standard used for adult unrelated volunteer donor transplantation for non-malignant diseases-for umbilical cord blood transplantation.We retrospectively studied 1199 paediatric donor-recipient pairs with allele-level HLA matching who received a single unit umbilical cord blood transplantation for non-malignant diseases reported to the Center for International Blood and Marrow Transplant Research or Eurocord and European Group for Blood and Marrow Transplant. Transplantations occurred between Jan 1, 2000, and Dec 31, 2012. The primary outcome was overall survival. The effect of HLA matching on survival was studied using a Cox regression model.Compared with HLA-matched transplantations, mortality was higher with transplantations mismatched at two (hazard ratio [HR] 1·55, 95% CI 1·08-2·21, p=0·018), three (2·04, 1·44-2·89, p=0·0001), and four or more alleles (3·15, 2·16-4·58, p0·0001). There were no significant differences in mortality between transplantations that were matched and mismatched at one allele (HR 1·18, 95% CI 0·80-1·72, p=0·39). Other factors associated with higher mortality included recipient cytomegalovirus seropositivity (HR 1·40, 95% CI 1·13-1·74, p=0·0020), reduced intensity compared with myeloablative conditioning regimens (HR 1·36, 1·10-1·68, p=0·0041), transplantation of units with total nucleated cell dose of more than 21 × 10These data support a change from current practice in that selection of unrelated umbilical cord blood units for transplantation for non-malignant diseases should consider allele-level HLA matching at HLA-A, HLA-B, HLA-C, and HLA-DRB1.National Cancer Institute; National Heart, Lung, and Blood Institute; National Institute for Allergy and Infectious Diseases; US Department of Health and Human Services-Health Resources and Services Administration; and US Department of Navy.

Rare Mendelian disorders increasingly contribute to our understanding of the genetic architecture of autoimmune disease and the key molecular pathways governing its pathogenesis. Early-onset autoimmune disease can arise through activating mutations in inflammatory signalling pathways or loss-of-function mutations in immunoregulatory proteins. We investigated the molecular basis of complex autoimmunity—characterised by the onset of insulin-dependent diabetes, cytopaenias, hepatitis, enteropathy and interstitial lung disease at age 10—in a 14-year-old boy of healthy non-consanguineous British parents. Immunological analysis revealed lymphopaenia with no naive T cells and a high proportion of activated T cells (table 1). Pathogenic variants in STAT3 and FOXP3 were excluded. The clinical course was refractory to intensive immunosuppression with prednisolone, sirolimus, tacrolimus, infliximab or rituximab, necessitating haematopoietic stem cell transplantation. Twenty-one months post-transplant, he is thriving off all immunosuppressive medication with complete remission of autoimmune disease (except diabetes). View this table: Table 1 Immunological and clinical parameters Ethical approval was granted (ref: 10/H0906/22) and written informed consent provided prior to study commencement. By whole exome sequencing of peripheral blood genomic DNA (Illumina MiSeq) and downstream bioinformatic filtering (Ingenuity Variant Analysis), we identified a single biologically plausible variant—a novel de novo heterozygous 2 bp deletion in tumour necrosis factor-alpha-induced protein 3 ( TNFAIP3 , figure 1A). TNFAIP3 encodes the ubiquitin-editing enzyme A20, a negative regulator of the nuclear factor-κB (NF-κB) pathway.1 A20 removes K63-linked ubiquitin chains from key adaptor proteins, replacing them with K48-linked polyubiquitin chains, to trigger proteasomal degradation and termination of the NF-κB activation cascade.2 Polymorphisms in …

Primary Immunodeficiencies (PID) although rare are serious; diagnosis is often delayed due to their non-specific presentation. The concept of PID has changed in recent years to a broader clinical phenotype, including autoimmunity, malignancy, immune dysregulation and allergy. Improved genetic diagnostics has greatly improved both our understanding of PID and our approach to diagnosis, enabling more accurate delineation. Haematopoietic Stem Cell Transplantation (HSCT) is an increasingly successful curative treatment for a widening range of severe PIDs; survival following HSCT is now 90% due to better preparation, less toxic chemotherapy, improved donor matching, better manipulation of stem cells and improved management of complications. Quality of life for PIDs such as Chronic Granulomatous Disease (CGD) is markedly better after HSCT than with supportive care. This article outlines the advances made in this rapidly advancing field in the last decade and offers practical advice on investigation and management of suspected or confirmed PID for the general paediatrician.

Background Our centre performed the first ex-vivo T-lymphocyte depleted (TCD) haploidentical allograft in 1987 in a child with PID. Different TCD methods have been used including CAMPATH-1M TCD marrow (n=34), CD34+ selected marrow (CD34-S, n=34), CD3/CD19 TCD PBSC (n=7), and CD3-TCRαβ/CD19 TCD PBSC (αβ-TCD, n=30)). This study aimed to examine transplant outcomes according to different methods in children with PID. Methods Between Jan 1987 and Mar 2019, 105 PID patients underwent first TCD allograft and were included in the study. Thirteen patients who received gene-modified add-back T cells were excluded. The main outcomes of interest were OS, EFS and graft failure. An event was defined as death, graft failure or second procedures for slipping chimerism. Other endpoints were neutrophil engraftment, GvHD, immune reconstitution and donor chimerism. Log-rank test was used to compare OS and EFS according to TCD methods. Cumulative incidences (CI) graft failure was calculated using a competing risk analysis, considering death as a competing event. Multilevel mixed effects modelling was performed for the longitudinal analysis of immune reconstitution and CAMPATH-1M was used as a reference group. Results Donors were haploidentical donor (n=84, 83%), MUD/MFD (n=9, 9%) and MMFD/MMUD (n=8, 8%). 94% received conditioning. Thirteen (12%) patients had aGvHD, of whom 3 had grade III-IV. None had cGvHD. The cause of death changed from predominantly infection (18/25, 72%) in CAMPATH-IM and CD34-S to non-infectious causes in all 6 deaths in CD3/CD19 and αβ-TCD. Analysis by TCD methods revealed a 5-year OS of 58% (95% CI, 40-73%) for CAMPATH-1M, 68% (49-81%) for CD34-S, 69% (22-91%) for CD3/CD19 TCD and 83% (61-93%) for (αβ-TCD (p=0.24). Age was a significant predictor of OS for non-SCID PID (p=0.02). The corresponding EFS was 46% (29-62%) for CAMPATH-1M, 47% (30-62%) for CD34-S, 69% (95% CI, 22-91%) for CD3/CD19 TCD and 83% (61-93%) for αβ-TCD (p=0.04) (Fig 1B) The CI of graft failure reduced significantly, from 29% (14-61%) for CAMPATH-1M, to 19% (95%CI, 8-45%) for CD34-S, 17% (2-18%) for CD3/CD19 TCD and none had graft failure in αβ-TCD (p=0.002) (Figure 1C). CD4+ lymphocytes were significantly higher in CD34-S at months 4 (p=0.02), 5 (p=0.01), and 6 (p=0.006) post-HCT and at month 4 (p=0.04) post-HCT in αβ-TCD when compared to CAMPATH-1M (Fig 1D). The median donor myeloid chimerism at last follow-up was higher in newer TCD; 100% (range, 0-100%) for αβ-TCD, 93% (0-100%) for CD3/CD 19 depletion, 6% (0 -49%) for CD34-S, 20% (0-100%) for CAMPATH-1M (p Conclusions Outcomes after CD3+TCR αβ/CD19+ depletion are superior to previously used TCD methods. In an experienced centre it is a safe alternative procedure and enables a wide spectrum of PID to be transplanted. The result has led to evolution of donor hierarchy in our centre.

Phosphoinositide 3-kinase δ (PI3Kδ), a lipid kinase consisting of a catalytic (p110δ, encoded by PIK3CD) and a regulatory subunit (p85, encoded by PIK3R1), generates the second messenger phosphatidylinositol (3,4,5)-trisphosphate (PIP3) in the plasma membrane of leukocytes downstream of antigen and cytokine receptors.1 Signaling via PDK1, AKT, mTOR and downstream targets such as FOXO1, contributes to the metabolic and transcriptional changes required for the expansion, differentiation and effector function of lymphocytes. Activating germline mutations in PIK3CD cause the immune dysregulatory disease activated PI3Kδ syndrome (APDS), usually presenting with recurrent sinopulmonary infections in childhood, herpesvirus infections and CD4+ lymphopenia, underscoring the important role of balanced p110δ activity in human adaptive immunity. Ablation of p110δ in mice leads to aberrant T cell responses and intestinal inflammation. In humans, immune dysregulation including severe colitis is present in many cancer patients who are treated with the p110δ-specific inhibitor Idelalisib. Recently, one patient with autosomal recessive deficiency of p85α and two patients with loss-of function mutations in p110δ have been described who developed humoral immunodeficiency and colitis.

Treosulfan is given off-label in pediatric allogeneic hematopoietic stem cell transplant. This study investigated treosulfan's pharmacokinetics (PKs), efficacy, and safety in a prospective trial. Pediatric patients (n = 87) receiving treosulfan-fludarabine conditioning were followed for at least 1 year posttransplant. PKs were described with a two-compartment model. During follow-up, 11 of 87 patients died and 12 of 87 patients had low engraftment (≤ 20% myeloid chimerism). For each increase in treosulfan area under the curve from zero to infinity (AUC(0-∞) ) of 1,000 mg hour/L the hazard ratio (95% confidence interval) for mortality increase was 1.46 (1.23-1.74), and the hazard ratio for low engraftment was 0.61 (0.36-1.04). A cumulative AUC(0-∞) of 4,800 mg hour/L maximized the probability of success (> 20% engraftment and no mortality) at 82%. Probability of success with AUC(0-∞) between 80% and 125% of this target were 78% and 79%. Measuring PK at the first dose and individualizing the third dose may be required in nonmalignant disease.

MHC class II deficiency is a rare, but life-threatening, primary combined immunodeficiency. Hematopoietic cell transplantation (HCT) remains the only curative treatment for this condition, but transplant survival in the previously published result was poor. We analyzed the outcome of 25 patients with MHC class II deficiency undergoing first HCT at Great North Children's Hospital between 1995 and 2018. Median age at diagnosis was 6.5 months (birth to 7.5 years). Median age at transplant was 21.4 months (0.1-7.8 years). Donors were matched family donors (MFDs; n = 6), unrelated donors (UDs; n = 12), and haploidentical donors (HIDs; n = 7). Peripheral blood stem cells were the stem cell source in 68% of patients. Conditioning was treosulfanbased in 84% of patients; 84% received alemtuzumab (n = 14) or anti-thymocyte globulin (n = 8) as serotherapy. With a 2.9-year median follow-up, OS improved from 33% (46-68%) for HCT before 2008 (n = 6) to 94% (66-99%) for HCT after 2008 (n = 19; P = .003). For HCT after 2008, OS according to donor was 100% for MFDs and UDs and 85% for HIDs (P = .40). None had grade III-IV acute or chronic graft-versus-host disease. Latest median donor myeloid and lymphocyte chimerism were 100% (range, 0-100) and 100% (range, 64-100), respectively. Latest CD4+ T-lymphocyte number was significantly lower in transplant survivors (n = 14) compared with posttransplant disease controls (P = .01). All survivors were off immunoglobulin replacement and had protective vaccine responses to tetanus and Haemophilus influenzae. None had any significant infection or autoimmunity. Changing transplant strategy in Great North Children's Hospital has significantly improved outcomes for MHC class II deficiency.

Bi-allelic inactivating mutations in DOCK8 cause a combined immunodeficiency characterised by severe pathogen infections, eczema, allergies, malignancy and impaired humoral responses. These clinical features result from functional defects in most lymphocyte lineages. Thus, DOCK8 plays a key role in immune cell function. Hematopoietic stem cell transplantation (HSCT) is curative for DOCK8 deficiency. While previous reports have described clinical outcomes for DOCK8 deficiency following HSCT, the effect on lymphocyte reconstitution and function has not been investigated. Our study determined whether defects in lymphocyte differentiation and function in DOCK8-deficient patients were restored following HSCT. DOCK8-deficient T and B lymphocytes exhibited aberrant activation and effector function in vivo and in vitro. Frequencies of αβ T and MAIT cells were reduced while γδT cells were increased in DOCK8-deficient patients. HSCT improved, abnormal lymphocyte function in DOCK8-deficient patients. Elevated total and allergen-specific IgE in DOCK8-deficient patients decreased over time following HSCT. Our results document the extensive catalogue of cellular defects in DOCK8-deficient patients, and the efficacy of HSCT to correct these defects, concurrent with improvements in clinical phenotypes. Overall, our findings provide mechanisms at a functional cellular level for improvements in clinical features of DOCK8 deficiency post-HSCT, identify biomarkers that correlate with improved clinical outcomes, and inform the general dynamics of immune reconstitution in patients with monogenic immune disorders following HSCT.

Background Rare Immunodeficiency, AutoInflammatory and AutoImmune Disease (RITA) network is a European Research Network that brings together the leading centres for rare immune disorders (RID). Objectives To know the state of the art about diseases registries and research networks in Europe regarding patients with RID. Methods On April 2018 an on-line survey was sent to all 126 RITA members, of whom 45 are healthcare providers and 8 patients/family organizations. All data were collected and analysed using Excel program. Results Ninety RITA members (71%) replied. Collectively, 27 members are coordinating 25 registries, 53 members are participating in 38 registries, and 27 members knew the existence of 16 registries without participating. Only two members are not involved in any registries. Data about 53 different registries were collected across 14 European countries. Almost 50% of registries collect data on autoimmune disorders, while others are dedicated to primary immunodeficiencies and autoinflammatory diseases (respectively 15 registries, 28%, and 12 registries, 23%). Fifteen registries (28%) enrolled patients with a single specific disorder: in particular, three registries are devoted to systemic lupus erythematosus, two registries to Kawasaki disease or Behcet disease, and single registry to juvenile dermatomyositis, juvenile systemic sclerosis, juvenile idiopathic arthritis (JIA)-related uveitis, systemic JIA, Blau syndrome, sarcoidosis, Guillain-Barre syndrome, and myasthenia gravis. More than 55000 patients with RID are enrolled. The majority of registries (36; 68%) enrol only patients from national territories. Among the internationals, six collect data on autoimmune disorders (Pharmachild, BrainWorks, EuroMyositis, EULAR web library, UKIVAS registry and JIR cohort), five on primary immunodeficiencies (ESID, EBMT, SCETIDE, PCID and HLH registry), and three are devoted to autoinflammatory diseases (Eurofever, Infevers, and ImmunAID), despite also ESID registry and JIR cohort collect data on autoinflammatory diseases. Data usually collected in these registries are demography, diagnosis, clinical manifestations, laboratory tests and treatment, while genetic and imaging data are less frequently reported (respectively in 38% and 9% of registries). A treatment safety profile is reported in 29 registries (55%). Collectively, fifteen biobanks are counted. Conclusion The survey highlighted the pivotal role of national and international organizations in Europe to collect and organize clinical data on immune diseases, allowing the rapidly growing knowledge on these rare disorders, creating research networks and providing significant numbers of data to support new discoveries in the field. RITA network could improve the coordination of these numerous entities, supporting initiatives of collaboration. As a first attempt, the present survey revealed that the collection of key parameters about patient safety, as well as outcome data and quality of life measures should be improved among the registries of RITA network. References [1] Beukelman T, Anink J, Duffy C, et al. A survey of national and multi-national registries and cohort studies in juvenile idiopathic arthritis: challenges and opportunities. Pediatric Rheumatology 2017;15(1):31. Disclosure of Interests Riccardo Papa: None declared, Andrew Cant: None declared, Christoph Klein: None declared, Mark Little: None declared, Nico M Wulffraat: None declared, Marco Gattorno Grant/research support from: MG has received unrestricted grants from Sobi and Novartis, Nicolino Ruperto Grant/research support from: The Gaslini Hospital, where NR works as full-time public employee, has received contributions (> 10.000 USD each) from the following industries in the last 3 years: BMS, Eli-Lilly, GlaxoSmithKline, F Hoffmann-La Roche, Janssen, Novartis, Pfizer, Sobi. This funding has been reinvested for the research activities of the hospital in a fully independent manner, without any commitment with third parties., Consultant for: Received honoraria for consultancies or speaker bureaus (

Liver disease in X-linked hyper IgM syndrome (XHIGM) is an important predictor of mortality. In case liver transplantation (LT) is required, a survival benefit is observed when LT is combined with HSCT. ispartof: JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY vol:143 issue:5 pages:1952-+ ispartof: location:United States status: published

Mutations in the coiled-coil and DNA-binding domains of STAT1 lead to delayed STAT1 dephosphorylation and subsequently gain-of-function. The associated clinical phenotype is broad and can include chronic mucocutaneous candidiasis (CMC) and/or combined immunodeficiency (CID). We report a case of CMC/CID in a 10-year-old boy due to a novel mutation in the small ubiquitin molecule (SUMO) consensus site at the C-terminal region of STAT1 leading to gain-of-function by impaired sumoylation. Immunodysregulatory features of disease improved after Janus kinase inhibitor (jakinib) treatment. Functional testing after treatment confirmed reversal of the STAT1 hyper-phosphorylation and downstream transcriptional activity. IL-17 and IL-22 production was, however, not restored with jakinib therapy (ruxolitinib), and the patient remained susceptible to opportunistic infection. In conclusion, a mutation in the SUMO consensus site of STAT1 can lead to gain-of-function that is reversible with jakinib treatment. However, full immunocompetence was not restored, suggesting that this treatment strategy might serve well as a bridge to definitive therapy such as hematopoietic stem cell transplant rather than a long-term treatment option.

Item does not contain fulltext Patient registries are instrumental for clinical research in rare diseases. They help to achieve a sufficient sample size for epidemiological and clinical research and to assess the feasibility of clinical trials. The European Society for Immunodeficiencies (ESID) registry currently comprises information on more than 25,000 patients with inborn errors of immunity (IEI). The prerequisite of a patient to be included into the ESID registry is an IEI either defined by a defect in a gene included in the disease classification of the international union of immunological societies, or verified by applying clinical criteria. Because a relevant number of patients, including those with common variable immunodeficiency (CVID), representing the largest group of patients in the registry, remain without a genetic diagnosis, consensus on classification of these patients is mandatory. Here, we present clinical criteria for a large number of IEI that were designed in expert panels with an external review. They were implemented for novel entries and verification of existing data sets from 2014, yielding a substantial refinement. For instance, 8% of adults and 27% of children with CVID (176 of 1704 patients) were reclassified to 22 different immunodeficiencies, illustrating progress in genetics, but also the previous lack of standardized disease definitions. Importantly, apart from registry purposes, the clinical criteria are also helpful to support treatment decisions in the absence of a genetic diagnosis or in patients with variants of unknown significance.

Despite the known importance of zinc for human immunity, molecular insights into its roles have remained limited. Here we report a novel autosomal recessive disease characterized by absent B cells, agammaglobulinemia and early onset infections in five unrelated families. The immunodeficiency results from hypomorphic mutations of SLC39A7, which encodes the endoplasmic reticulum-to-cytoplasm zinc transporter ZIP7. Using CRISPR-Cas9 mutagenesis we have precisely modeled ZIP7 deficiency in mice. Homozygosity for a null allele caused embryonic death, but hypomorphic alleles reproduced the block in B cell development seen in patients. B cells from mutant mice exhibited a diminished concentration of cytoplasmic free zinc, increased phosphatase activity and decreased phosphorylation of signaling molecules downstream of the pre-B cell and B cell receptors. Our findings highlight a specific role for cytosolic Zn2+ in modulating B cell receptor signal strength and positive selection.

The European Academy of Allergy and Clinical Immunology (EAACI) organized the first European Strategic Forum on Allergic Diseases and Asthma. The main aim was to bring together all relevant stakeholders and decision-makers in the field of allergy, asthma and clinical Immunology around an open debate on contemporary challenges and potential solutions for the next decade. The Strategic Forum was an upscaling of the EAACI White Paper aiming to integrate the Academy's output with the perspective offered by EAACI's partners. This collaboration is fundamental for adapting and integrating allergy and asthma care into the context of real-world problems. The Strategic Forum on Allergic Diseases brought together all partners who have the drive and the influence to make positive change: national and international societies, patients’ organizations, regulatory bodies and industry representatives. An open debate with a special focus on drug development and biomedical engineering, big data and information technology and allergic diseases and asthma in the context of environmental health concluded that connecting science with the transformation of care and a joint agreement between all partners on priorities and needs are essential to ensure a better management of allergic diseases and asthma in the advent of precision medicine together with global access to innovative and affordable diagnostics and therapeutics. © 2019 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

Background Mismatched related and unrelated donor stem cell transplantation is considered a high risk transplant associated with high risk of graft loss, graft versus host disease (GvHD) and transplant related mortality (TRM). Alternative graft manipulation strategies have been employed over the last 10 years to reduce these risks, and here we present an analysis of these strategies in primary immunodeficiency (PID). Methods Between 2006–2017, 147 PID patients received 155 mismatched grafts; 30 TCRαβ/CD19 depleted, 43 Cord (72% with no serotherapy), 17 CD34 +selection with T cell add-back and 65 unmanipulated bone marrow or peripheral blood stem cell grafts. Results The estimated 8 year survival of the entire cohort was 79%, TRM was 21.7% and graft failure rate was 6%. Comparable rates of survival were recorded among different graft manipulation strategies. Post-transplant viral reactivation, aGvHD grades II-IV and chronic GvHD complicated 49.6%, 35% and 15% of the transplants, respectively. The use of TCR αβ/CD19 depletion in this study has reduced the occurrence of grade II-IV aGvHD among mismatched transplants: 40% among CD34+/T cell add-back to 11.5% with TCR αβ/CD19 depleted grafts. The same pattern was seen in terms of cGvHD where none of the recipients of TCR αβ/CD19 depleted grafts had cGvHD compared to 38.4% amongst CD34+/T cell add-back. However, one drawback of TCR αβ/CD19 depleted HSCT was the increased incidence of post-transplant viraemia reaching 70% versus 37%–49% among other graft manipulations. T cell immune reconstitution was robust among cord transplants however with a high incidence of aGvHD grade II-IV 56.7%. Stable full donor engraftment was significantly higher at 80% among TCRαβ+/CD19 +depleted and cord transplants versus 40%–60% among the other groups. Conclusions Rapidly accessible cord and haploidentical grafts are suitable alternatives for patients with no HLA matched donor. Cord transplantation without serotherapy and TCRαβ+/CD19 +depleted grafts produced comparable survival rates of around 80% and exhibited higher donor chimerism compared to other strategies of graft manipulation.

PURPOSE\ud \ud To investigate the clinical and functional aspects of MST1 (STK4) deficiency in a profoundly CD4-lymphopenic kindred with a novel homozygous nonsense mutation in STK4. Although recent studies have described the cellular effects of murine Mst1 deficiency, the phenotype of MST1-deficient human lymphocytes has yet to be fully explored. Patient lymphocytes were therefore investigated in the context of current knowledge of murine Mst1 deficiency.\ud \ud METHODS\ud \ud Genetic etiology was identified by whole exome sequencing of genomic DNA from two siblings, combined with linkage analysis in the wider family. MST1 protein expression was assessed by immunoblotting. The ability of patient lymphocytes to adhere to ICAM-1 under flow conditions was measured, and transwell assays were used to assess chemotaxis. Chemokine receptor expression was examined by flow cytometry and receptor signalling by immunoblotting.\ud \ud RESULTS\ud \ud A homozygous nonsense mutation in STK4 (c.442C > T, p.Arg148Stop) was found in the patients, leading to a lack of MST1 protein expression. Patient leukocytes exhibited deficient chemotaxis after stimulation with CXCL11, despite preserved expression of CXCR3. Patient lymphocytes were also unable to bind effectively to immobilised ICAM-1 under flow conditions, in keeping with a failure to develop high affinity binding.\ud \ud CONCLUSION\ud \ud The observed abnormalities of adhesion and migration imply a profound trafficking defect among human MST1-deficient lymphocytes. By analogy with murine Mst1 deficiency and other defects of leucocyte trafficking, this is likely to contribute to immunodeficiency by impairing key aspects of T-cell development and function such as positive selection in the thymus, thymic egress and immune synapse formation in the periphery.

Introduction Studies focusing on post-HCT AIC in large cohorts of patients transplanted for primary immunodeficiency (PID) are lacking. Objectives We conducted a retrospective analysis of incidence, risk factors, outcome of post-HCT AIC in children with PID and B-cell function following rituximab treatment. Methods Between January 1987-December 2018, 502 PID patients who underwent first HCT for PID at our center were included. Cumulative incidence (CI) of post-HCT AIC was calculated using a competing risk analysis, considering death as a competing event. Fine-and-Gray test was used to identify risk factors of AIC. The selected variables: gender, age at HCT, indication for HCT (SCID versus non-SCID PID), pre-HCT AIC, donor type, donor-recipient ABO matching, stem cell source, ex-vivo T-cell depletion (TCD), stem cell doses, conditioning regimen, serotherapy, GvHD prophylaxis, acute GvHD, chronic GvHD and viraemia. B-lymphocyte immune reconstitution kinetics was compared between surviving patients with post-HCT AIC without rituximab (n=18), post-HCT treated with rituximab (n=12) and controls (n=24). Results 36 (CI, 9%) developed post-HCT AIC, with median onset at 6.5 months (2.5 months - 18.2 years). On univariate analysis, pre-HCT AIC (Fig. A), mismatched donor, alemtuzumab (Fig. B), ATG, acute GvHD (Fig. C) and chronic GvHD were significantly associated with post-HCT AIC. After multivariate analysis, alemtuzumab (p=0.02) was independently associated with post-HCT AIC. Corticosteroid and high-dose IVIg (2gm/kg) achieved remission in 50% (n=18), additional rituximab led to remission in 25% (n=9), and the remaining 25% were treated with various modalities including sirolimus (n=5), bortezomib (n=3), mycophenolate mofetil (n=2), splenectomy (n=2), and second HCT (n=3). The mortality of post-HCT AIC reduced from 25% (4/16) prior to 2011 to 5% (1/20) after 2011. The median follow-up of 5.8 years (0.4-29.1) showed that 26 of 30 survivors (87%) were in complete remission, 4 (13%) were in remission with sirolimus and low dose steroid. Of 12 survivors who were treated with rituximab, immunoglobulin substitution was discontinued in 7 (52%), and 5 (48%) required on-going IVIg replacement. The median interval between HCT and rituximab was 1.95 years (0.96-19.9) in patients who were IVIg dependent and 0.73 (0.30-2.3) in patients who were IVIg-free on last follow-up (p=0.17). B-lymphocyte immune reconstitution kinetics was significant slowly in patients with post-AIC with/without rituximab (Fig. D). Conclusions 5-year CI of post-HCT AIC in children with PID was 9% and there is risk of very late onset post-HCT AIC in patients with Artemis and RAG1 mutations, and activated PI3 delta syndrome. Alemtuzumab pk study might play a role in reducing the incidence of post-HCT AIC. Sirolimus is an effective steroid-sparing immunomodulator in refractory/frequently relapsing post-HCT AIC.

Activated phosphoinositide 3-kinase δ syndrome (APDS), also known as PASLI disease (p110d-activating mutation causing senescent T cells, lymphadenopathy, and immunodeficiency) are combined immunodeficiencies resulting from gain-of-function mutations in the genes (PIK3CD and PIK3R1) encoding the subunits of phosphoinositide 3-kinase δ (PI3Kδ) and were first described in 2013. These mutations result in the hyperactivation of the PI3K/AKT/mTOR/S6K signally pathways. In this mini-review we have detailed the current treatment options for APDS. These treatments including conventional immunodeficiency therapies such as immunoglobulin replacement, antibiotic prophylaxis, and hematopoietic stem cell transplant. We also discuss the more targeted therapies of mTOR inhibition with sirolimus and selective PI3Kδ inhibitors.

Patients with juvenile idiopathic arthritis (JIA) can experience a severe disease course, with progressive destructive polyarthritis refractory to conventional therapy with disease-modifying antirheumatic drugs including biologics, as well as life-threatening complications including macrophage activation syndrome (MAS). Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative immunomodulatory strategy for patients with such refractory disease. We treated 16 patients in 5 transplant centers between 2007 and 2016: 11 children with systemic JIA and 5 with rheumatoid factor-negative polyarticular JIA; all were either refractory to standard therapy, had developed secondary hemophagocytic lymphohistiocytosis/MAS poorly responsive to treatment, or had failed autologous HSCT. All children received reduced toxicity fludarabine-based conditioning regimens and serotherapy with alemtuzumab. Fourteen of 16 patients are alive with a median follow-up of 29 months (range, 2.8-96 months). All patients had hematological recovery. Three patients had grade II-IV acute graft-versus-host disease. The incidence of viral infections after HSCT was high, likely due to the use of alemtuzumab in already heavily immunosuppressed patients. All patients had significant improvement of arthritis, resolution of MAS, and improved quality of life early following allo-HSCT; most importantly, 11 children achieved complete drug-free remission at the last follow-up. Allo-HSCT using alemtuzumab and reduced toxicity conditioning is a promising therapeutic option for patients with JIA refractory to conventional therapy and/or complicated by MAS. Long-term follow-up is required to ascertain whether disease control following HSCT continues indefinitely.

Despite the known importance of zinc for human immunity, molecular insights into its roles have remained limited. Here we report a novel autosomal recessive disease characterized by absent B cells, agammaglobulinemia and early onset infections in five unrelated families. The immunodeficiency results from hypomorphic mutations of SLC39A7, which encodes the endoplasmic reticulum-to-cytoplasm zinc transporter ZIP7. Using CRISPR-Cas9 mutagenesis we have precisely modeled ZIP7 deficiency in mice. Homozygosity for a null allele caused embryonic death, but hypomorphic alleles reproduced the block in B cell development seen in patients. B cells from mutant mice exhibited a diminished concentration of cytoplasmic free zinc, increased phosphatase activity and decreased phosphorylation of signaling molecules downstream of the pre-B cell and B cell receptors. Our findings highlight a specific role for cytosolic Zn

Item does not contain fulltext BACKGROUND: Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is a negative immune regulator. Heterozygous CTLA4 germline mutations can cause a complex immune dysregulation syndrome in human subjects. OBJECTIVE: We sought to characterize the penetrance, clinical features, and best treatment options in 133 CTLA4 mutation carriers. METHODS: Genetics, clinical features, laboratory values, and outcomes of treatment options were assessed in a worldwide cohort of CTLA4 mutation carriers. RESULTS: We identified 133 subjects from 54 unrelated families carrying 45 different heterozygous CTLA4 mutations, including 28 previously undescribed mutations. Ninety mutation carriers were considered affected, suggesting a clinical penetrance of at least 67%; median age of onset was 11 years, and the mortality rate within affected mutation carriers was 16% (n = 15). Main clinical manifestations included hypogammaglobulinemia (84%), lymphoproliferation (73%), autoimmune cytopenia (62%), and respiratory (68%), gastrointestinal (59%), or neurological features (29%). Eight affected mutation carriers had lymphoma, and 3 had gastric cancer. An EBV association was found in 6 patients with malignancies. CTLA4 mutations were associated with lymphopenia and decreased T-, B-, and natural killer (NK) cell counts. Successful targeted therapies included application of CTLA-4 fusion proteins, mechanistic target of rapamycin inhibitors, and hematopoietic stem cell transplantation. EBV reactivation occurred in 2 affected mutation carriers after immunosuppression. CONCLUSIONS: Affected mutation carriers with CTLA-4 insufficiency can present in any medical specialty. Family members should be counseled because disease manifestation can occur as late as 50 years of age. EBV- and cytomegalovirus-associated complications must be closely monitored. Treatment interventions should be coordinated in clinical trials.

Background Standard myeloablative conditioning regimens for children with hematological malignancies undergoing allogeneic HSCT are based mainly on total body irradiation or busulfan. Their serious short- and long-term side effects warranted the exploration of less toxic alternatives. Treosulfan is increasingly used for adults and children before HSCT due to its potent immunosuppressive and cytotoxic effects combined with low organ toxicity. Procedure To further investigate the role of treosulfan conditioning in children, the EBMT Pediatric diseases working party performed a retrospective analysis of 193 children with hematological malignancies (ALL n = 71, AML n = 47, MDS/MPS n = 40, other leukemia/lymphoma n = 25) undergoing allogeneic HSCT following treosulfan between January 2005 and July 2010. Results Early regimen-related toxicity was low and mainly gastrointestinal. Veno-occlusive disease and neurological toxicity were rare. There was no association of toxicity with type of disease or treosulfan dose. High-grade early toxicity was not higher in infants or patients undergoing second or later transplantation. Treatment related mortality was low at 14%. Three-year event-free survival was 45 ± 4% and not significantly influenced by number of transplants, however it appeared to be significantly better for infants (P = 0.022). When compared to treosulfan plus fludarabine, the combination of treosulfan, fludarabine and an alkylator (either thiotepa or melphalan) resulted in significantly better overall survival (OS, P = 0.048) and a trend toward better EFS. Conclusions Treosulfan based conditioning is a safe and effective approach for children with hematological malignancies, including and importantly for infants and those patients undergoing second or later transplantation. Pediatr Blood Cancer © 2015 Wiley Periodicals, Inc.

WOS: 000352238600022, PubMed ID: 25595268, 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., German Federal Ministry of Education and Research (BMBF)Federal Ministry of Education & Research (BMBF) [01 EO 0803]; Dutch Cancer SocietyKWF Kankerbestrijding [2013-5883]; Medical Research CouncilMedical Research Council UK (MRC) [G0501468], Supported by the German Federal Ministry of Education and Research (BMBF 01 EO 0803). C.L. is supported by a clinical fellowship from the Dutch Cancer Society (2013-5883).

To the Editor, In 2011, Moratto et al. [1]. identified age at haematopoietic stem cell transplantation (HSCT) as a risk modifier for complications inWiskott-Aldrich syndrome (WAS); of note, complications appear to be 1.5 times more likely in children transplanted at ages 2–5, compared to younger than 2 (RR = 1.53; CI, 0.90–2.58; P = 0.130). This reinforces the importance of prompt recognition, diagnosis and assessment for HSCT in patients with suspected WAS. We evaluated the presenting features in boys with WAS mutations transplanted at the Great North Childrens’ Hospital, Newcastle-upon-Tyne between 1989 and 2015 in order to identify any delay in diagnosis and causative factors, including misdiagnosis, and clarify the role of mean platelet volume in making a diagnosis of WAS. We sought to identify key discriminating diagnostic features in order to aid timely diagnosis and transplantation of these patients. Data was collected retrospectively from written and electronic medical records of 20 boys with WAS mutations, for which all families had given prior written consent. Information regarding date and nature of symptom onset, time elapsed until diagnosis, mean platelet volume at presentation, age at transplantation and outcome were recorded in an anonymised spreadsheet. Symptomatology was coded as one or more of the following: infectious and immunological, including autoimmunity; eczema; bruising and petechiae; and bleeding. No differentiation was made between WAS and XLT due to no significant difference in platelet counts, platelet size and bleeding episodes in these conditions. Median age at symptom onset was 2 months (birth – 9 months) and at diagnosis was 1 year (2 months – 14.1 years). Median interval between symptom onset and diagnosis was 8 months (2 weeks – 13.8 years). The most common presenting symptom was bleeding (13 reports, 65 %). The subsequent most common symptoms were bruising (11, 55 %); eczema and skin disease (9, 45 %) and immunological and infectious (7, 35 %). Initial documented impressions included nonaccidental injury [1], congenital cytomegalovirus infection [1] and suspected ITP [2]. The most common combination of symptoms at presentation was bruising with eczema, in 7 (35 %), bleeding and bruising, 5 (25 %); bleeding and eczema, 5 (25 %); bleeding and infective/immunological, 4 (20 %); bruising and infective or immunological, 4 (20 %), infective or immunological and eczema, 1 (5 %) patient. There was no documented family history of WAS or XLT. Eight patients (40 %) had a recorded mean platelet volume (MPV) following presentation to our unit. Median MPV was 4.85 fl (range: 3.6–21); only 3 patients had a volume < 5 fl (Fig. 1). One result was recorded as Blow^ and so was omitted from analysis. Our results show a lag between onset of symptoms and confirmed diagnosis of WAS of 8 months. A diagnostic delay in WAS (and other primary immunodeficiency disorders) of * Christo Tsilifis ctsilifis@gmail.com

Background Absent T-cell immunity resulting in life-threatening infections provides a clear rationale for hematopoetic stem cell transplantation (HSCT) in patients with severe combined immunodeficiency (SCID). Combined immunodeficiencies (CIDs) and "atypical" SCID show reduced, not absent T-cell immunity. If associated with infections or autoimmunity, they represent profound combined immunodeficiency (P-CID), for which outcome data are insufficient for unambiguous early transplant decisions. Objectives We sought to compare natural histories of severity-matched patients with/without subsequent transplantation and to determine whether immunologic and/or clinical parameters may be predictive for outcome. Methods In this prospective and retrospective observational study, we recruited nontransplanted patients with P-CID aged 1 to 16 years to compare natural histories of severity-matched patients with/without subsequent transplantation and to determine whether immunologic and/or clinical parameters may be predictive for outcome. Results A total of 51 patients were recruited (median age, 9.6 years). Thirteen of 51 had a genetic diagnosis of "atypical" SCID and 14 of 51 of CID. About half of the patients had less than 10% naive T cells, reduced/absent T-cell proliferation, and at least 1 significant clinical event/year, demonstrating their profound immunodeficiency. Nineteen patients (37%) underwent transplantation within 1 year of enrolment, and 5 of 51 patients died. Analysis of the HSCT decisions revealed the anticipated heterogeneity, favoring an ongoing prospective matched-pair analysis of patients with similar disease severity with or without transplantation. Importantly, so far neither the genetic diagnosis nor basic measurements of T-cell immunity were good predictors of disease evolution. Conclusions The P-CID study for the first time characterizes a group of patients with nontypical SCID T-cell deficiencies from a therapeutic perspective. Because genetic and basic T-cell parameters provide limited guidance, prospective data from this study will be a helpful resource for guiding the difficult HSCT decisions in patients with P-CID.

Purpose We aimed to achieve a retrospective molecular diagnosis by applying state-of-the-art genomic sequencing methods to past patients with T-B+NK+ severe combined immunodeficiency (SCID). We included identification of copy number variations (CNVs) by whole exome sequencing (WES) using the CNV calling method ExomeDepth to detect gene alterations for which routine Sanger sequencing analysis is not suitable, such as large heterozygous deletions. Methods Of a total of 12 undiagnosed patients with T-B+NK+ SCID, we analyzed eight probands by WES, using GATK to detect single nucleotide variants (SNVs) and small insertions and deletions (INDELs) and ExomeDepth to detect CNVs. Results We found heterozygous single- or multi-exon deletions in IL7R, a known disease gene for autosomal recessive T-B+NK+ SCID, in four families (seven patients). In three families (five patients), these deletions coexisted with a heterozygous splice site or nonsense mutation elsewhere in the same gene, consistent with compound heterozygosity. In our cohort, about a quarter of T-B+NK+ SCID patients (26%) had such compound heterozygous IL7R deletions. Conclusions We show that heterozygous IL7R exon deletions are common in T-B+NK+ SCID and are detectable by WES. They should be considered if Sanger sequencing fails to detect homozygous or compound heterozygous IL7R SNVs or INDELs. Electronic supplementary material The online version of this article (doi:10.1007/s10875-016-0343-9) contains supplementary material, which is available to authorized users.

A prospective cohort study of children with primary immunodeficiencies undergoing hematopoietic stem cell transplant in the United Kingdom investigated the extent and significance of Cryptosporidium carriage in this high risk group. Three of 42 children recruited were infected with Cryptosporidium, a lower proportion than previously described. One had serious disease. The underlying immunodeficiency likely had a bearing on the clinical presentation and possible outcome of infection.

Accumulation of CD3(+) T-cell receptor (TCR)αβ(+)CD4(-)CD8(-) double-negative T cells (DNT) is a hallmark of autoimmune lymphoproliferative syndrome (ALPS). DNT origin and differentiation pathways remain controversial. Here we show that human ALPS DNT have features of terminally differentiated effector memory T cells reexpressing CD45RA(+) (TEMRA), but are CD27(+)CD28(+)KLRG1(-) and do not express the transcription factor T-bet. This unique phenotype was also detected among CD4(+) or CD8(+) ALPS TEMRA cells. T-cell receptor β deep sequencing revealed a significant fraction of shared CDR3 sequences between ALPS DNT and both CD4(+) and CD8(+)TEMRA cells. Moreover, in ALPS patients with a germ line FAS mutation and somatic loss of heterozygosity, in whom biallelic mutant cells can be tracked by absent Fas expression, Fas-negative T cells accumulated not only among DNT, but also among CD4(+) and CD8(+)TEMRA cells. These data indicate that in human Fas deficiency DNT cannot only derive from CD8(+), but also from CD4(+) T cells. Furthermore, defective Fas signaling leads to aberrant transcriptional programs and differentiation of subsets of CD4(+) and CD8(+) T cells. Accumulation of these cells before their double-negative state appears to be an important early event in the pathogenesis of lymphoproliferation in ALPS patients.