Wiskott-Aldrich Syndrome: A study on 577 patients defining the genotype as a predictive biomarker for disease severity.

WAS is a multifaceted monogenic disorder with a broad disease spectrum and variable disease severity and a variety of treatment options including allogeneic hematopoietic stem cell transplantation (HSCT) and gene therapy (GT). No reliable biomarker exists to predict disease course and outcome for individual patients. A total of 577 patients with a WAS variant from 26 countries and a median follow-up of 8.9 years (0.3-71.1), totaling 6118 patient-years, were included in this international retrospective study. Overall survival (OS) of the cohort (censored at HSCT or GT) was 82% (95% CI 78-87) at 15 years and 70% (61-80) at 30 years of age. The type of variant was predictive of outcome: patients with a missense variant in exons 1 or 2 or with the intronic hotspot variant c.559+5G>A (class I variants) had a 15-year OS of 93% (89-98) and a 30-year OS of 91% (86-97), compared to 71% (62-81) and 48% (34-68) in patients with any other variant (class II; p<0.0001). The cumulative incidence rates of disease-related complications such as severe bleeding (p=0.007), life-threatening infection (p<0.0001), and autoimmunity (p=0.004) occurred significantly later in patients with a class I variant. The cumulative incidence of malignancy (p=0.6) was not different between classes I and II. This study represents the largest cohort of WAS patients studied so far. It confirms the spectrum of disease severity and quantifies the risk for specific disease-related complications. The class of variant is a biomarker to predict the outcome for WAS patients.

Pharmacokinetics, safety, and efficacy of 20% subcutaneous immunoglobulin (Ig20Gly) administered weekly or every 2 weeks in Japanese patients with primary immunodeficiency diseases: a phase 3, open-label study.

This phase 3, open-label, multidose study (NCT04346108) evaluated the pharmacokinetics, safety, tolerability, and efficacy of immunoglobulin subcutaneous (human) 20% solution (Ig20Gly) administered weekly and every 2 weeks in Japanese patients with primary immunodeficiency diseases (PIDs). The study was conducted at eight study sites in Japan and enrolled patients aged ≥2 years with PIDs treated using a stable intravenous immunoglobulin dose for ≥3 months prior to the study. Patients received intravenous immunoglobulin every 3 or 4 weeks at pre-study dose (200-600 mg/kg) for 13 weeks (Epoch 1), subcutaneous Ig20Gly (50-200 mg/kg) once weekly for 24 weeks (Epoch 2), and Ig20Gly (100-400 mg/kg) every 2 weeks for 12 weeks (Epoch 3). The primary endpoint was serum total immunoglobulin G (IgG) trough levels during Epochs 2 and 3. Overall, 17 patients were enrolled (median [range] age: 24 [5-69] years; 59% male) and participated in Epochs 1 and 2; seven patients entered Epoch 3. Serum total IgG trough levels were maintained at >8 g/l: geometric means (95% confidence intervals) at the end of Epochs 2 and 3 were 8.56 (8.03-9.12) g/l and 8.39 (7.89-8.91) g/l, respectively. Related treatment-emergent adverse events were all mild in severity; the most common treatment-emergent adverse events (excluding infections) in Epochs 2 and 3 were injection site swelling (24%) and injection site erythema (18%). This is the first trial to demonstrate the efficacy and favourable safety profile of 20% subcutaneous immunoglobulin administered every 2 weeks in adult and paediatric Japanese patients with PIDs.

Knockdown of the Shwachman-Diamond syndrome gene, SBDS, induces galectin-1 expression and impairs cell growth.

Shwachman-Diamond syndrome (SDS) is an autosomal recessive disorder characterized by exocrine pancreatic insufficiency and bone marrow failure. The depletion of SBDS protein by RNA interference has been shown to cause inhibition of cell proliferation in several cell lines. However, the precise mechanism by which the loss of SBDS leads to inhibition of cell growth remains unknown. To evaluate the impaired growth of SBDS-knockdown cells, we analyzed Epstein-Barr virus-transformed lymphoblast cells (LCLs) derived from two patients with SDS (c. 183_184TA > CT and c. 258 + 2 T > C). After 3 days of culture, the growth of LCL-SDS cell lines was considerably less than that of control donor cells. By annealing control primer-based GeneFishing PCR screening, we found that galectin-1 (Gal-1) mRNA expression was elevated in LCL-SDS cells. Western blot analysis showed that the level of Gal-1 protein expression was also increased in LCL-SDS cells as well as in SBDS-knockdown 32Dcl3 murine myeloid cells. We confirmed that recombinant Gal-1 inhibited the proliferation of both LCL-control and LCL-SDS cells and induced apoptosis (as determined by annexin V-positive staining). These results suggest that the overexpression of Gal-1 contributes to abnormal cell growth in SBDS-deficient cells.

Case Report: The leopard sign as a potential characteristic of chronic granulomatous disease-associated colitis, unrelated to colitis severity.

Background: Chronic granulomatous disease (CGD) is an inborn immune disorder in which the phagocytic system cannot eradicate pathogens, and autoinflammation occurs. Approximately half of the patients have associated gastrointestinal symptoms. Although most cases with CGD-associated colitis present nonspecific histology, colonoscopy in some cases shows brownish dots over a yellowish oedematous mucosa, which is termed a "leopard sign". However, the significance of these signs remains unclear. Methods: We collected data from patients with CGD whose colonoscopic findings showed the leopard sign. Results: Three patients with CGD and leopard signs were enrolled in this study. One patient underwent colonoscopy for frequent diarrhoea and weight gain failure, and another for anal fistula. The third patient was without gastrointestinal symptoms and underwent colonoscopy as a screening test before allogeneic haematopoietic cell transplantation (HCT). Endoscopic findings showed a mild leopard sign in the first case; however, non-contiguous and diffuse aphthae were observed throughout the colon. The other two cases were unremarkable except for the leopard sign. All the patients achieved remission with oral prednisolone or HCT. One patient underwent colonoscopy after HCT; results revealed improvements in endoscopy (including the leopard sign) and histological findings. However, another patient underwent colonoscopy after prednisolone treatment; this revealed no change in the leopard sign. Conclusion: The leopard sign in the colon may be a characteristic endoscopic finding of CGD, even in patients who do not develop severe gastrointestinal symptoms; however, it does not reflect the severity of CGD-associated colitis.

Fatal COVID-19 Infection in Two Children with STAT1 Gain-of-Function.

While SARS-CoV-2 infection causes a mild disease in most children, SARS-CoV-2 infection may be lethal in a few of them. In the defense against SARS-CoV-2, type I interferons are key players, and several studies have identified a defective or neutralized interferon response as the cause of overwhelming viral infection. However, inappropriate, untimely, or excessive interferon production may also be detrimental to the host. Here, we describe two patients with STAT1 gain-of-function (GOF), a known type I interferonopathy, who died of COVID-19. Whole-exome sequencing and interferon-gamma-activated sequence (GAS) and interferon-sensitive responsive element (ISRE) reporter assay were performed to identify and characterize STAT1 variants. Patient 1 developed hemophagocytic lymphohistiocytosis (HLH) in the context of COVID-19 infection and died in less than a week at the age of 4 years. Patient 2 developed a high fever, cough, and hypoxemia and succumbed to COVID-19 pneumonia at the age of 5 years. Two heterozygous missense variants, p.E563Q and p.K344E, in STAT1 were identified. Functional validation by reporter assay and immunoblot confirmed that both variants are gain-of-function (GOF). GOF variants transiently expressing cells exhibited enhanced upregulation of downstream genes, including ISG15, MX1, and OAS1, in response to IFN-α stimulation. A catastrophic course with HLH or acute respiratory failure is thought to be associated with inappropriate immunoregulatory mechanisms to handle SARS-CoV-2 in STAT1 GOF. While most patients with inborn errors of immunity who developed COVID-19 seem to handle it well, these cases suggest that patients with STAT1-GOF might be at risk of developing fatal complications due to SARS-CoV-2.

[Hematopoietic cell transplantation for monogenic inflammatory bowel disease].

The pathogenesis of inflammatory bowel disease (IBD) may include immune dysregulation. About 20% of inborn errors of immunity (IEIs) are related to IBD, and more than 60 IEIs are known to present IBD. Monogenic IBDs include those that are refractory to traditional treatment and can be cured by allogeneic hematopoietic cell transplantation (HCT), making early diagnosis and treatment essential. In this report, we present a series of monogenic IBDs that are relatively frequently found in Japan, such as interleukin (IL)-10/IL-10 receptor deficiency, chronic granulomatous disease, XIAP deficiency, immunodysregulation, polyendocrinopathy, enteropathy, and X-linked (IPEX) syndrome, NEMO deficiency, and A20 haploinsufficiency and will describe the features of each IEI and the indications for HCT.

Precision medicine in monogenic inflammatory bowel disease: proposed mIBD REPORT standards.

Owing to advances in genomics that enable differentiation of molecular aetiologies, patients with monogenic inflammatory bowel disease (mIBD) potentially have access to genotype-guided precision medicine. In this Expert Recommendation, we review the therapeutic research landscape of mIBD, the reported response to therapies, the medication-related risks and systematic bias in reporting. The mIBD field is characterized by the absence of randomized controlled trials and is dominated by retrospective observational data based on case series and case reports. More than 25 off-label therapeutics (including small-molecule inhibitors and biologics) as well as cellular therapies (including haematopoietic stem cell transplantation and gene therapy) have been reported. Heterogeneous reporting of outcomes impedes the generation of robust therapeutic evidence as the basis for clinical decision making in mIBD. We discuss therapeutic goals in mIBD and recommend standardized reporting (mIBD REPORT (monogenic Inflammatory Bowel Disease Report Extended Phenotype and Outcome of Treatments) standards) to stratify patients according to a genetic diagnosis and phenotype, to assess treatment effects and to record safety signals. Implementation of these pragmatic standards should help clinicians to assess the therapy responses of individual patients in clinical practice and improve comparability between observational retrospective studies and controlled prospective trials, supporting future meta-analysis.

Bone Marrow Failure and Immunodeficiency Associated with Human RAD50 Variants.

PURPOSE: The MRE11-RAD50-NBN (MRN) complex plays a key role in recognizing and signaling DNA double-strand breaks. Pathogenic variants in NBN and MRE11 give rise to the autosomal-recessive diseases, Nijmegen breakage syndrome (NBS) and ataxia telangiectasia-like disorder, respectively. The clinical consequences of pathogenic variants in RAD50 are incompletely understood. We aimed to characterize a newly identified RAD50 deficiency/NBS-like disorder (NBSLD) patient with bone marrow failure and immunodeficiency. METHODS: We report on a girl with microcephaly, mental retardation, bird-like face, short stature, bone marrow failure and B-cell immunodeficiency. We searched for candidate gene by whole-exome sequencing and analyzed the cellular phenotype of patient-derived fibroblasts using immunoblotting, radiation sensitivity assays and lentiviral complementation experiments. RESULTS: Compound heterozygosity for two variants in the RAD50 gene (p.Arg83His and p.Glu485Ter) was identified in this patient. The expression of RAD50 protein and MRN complex formation was maintained in the cells derived from this patient. DNA damage-induced activation of the ATM kinase was markedly decreased, which was restored by the expression of wild-type (WT) RAD50. Radiosensitivity appeared inconspicuous in the patient-derived cell line as assessed by colony formation assay. The RAD50R83H missense substitution did not rescue the mitotic defect in complementation experiments using RAD50-deficient fibroblasts, whereas RAD50WT did. The RAD50E485X nonsense variant was associated with in-frame skipping of exon 10 (p.Glu485_545del). CONCLUSION: These findings indicate important roles of RAD50 in human bone marrow and immune cells. RAD50 deficiency/NBSLD can manifest as a distinct inborn error of immunity characterized by bone marrow failure and B-cell immunodeficiency.

Patient-reported outcomes in patients with primary immunodeficiency diseases in Japan: baseline results from a prospective observational study.

Introduction: Primary immunodeficiency diseases (PIDs) are rare inherited diseases resulting in impaired immunity. People with PID experience lower health-related quality of life (HR-QOL) and disease-related burdens in daily activities. This ongoing, prospective observational study aims to evaluate disease activity, treatment status, treatment-related burden, daily activities, and HR-QOL in patients with PID in Japan over a 1-year period. In this interim report (database lock: July 29, 2022), we present baseline results. Methods: Participants were enrolled between November 2021 and May 2022; data were collected four times/year per participant until May 2023 using an online electronic patient-reported outcomes system. Patients with PID and healthy volunteers aged ≥12 years, residing in Japan, and with access to a smartphone were eligible. HR-QOL (primary endpoint) was assessed by the EuroQol-5 Dimensions-5 Levels (EQ-5D-5L) and the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36). Work productivity was assessed by the Work Productivity and Activity Impairment (WPAI) Questionnaire. Other aspects of PID and burden were assessed with a new questionnaire developed in-house. The study is registered at the University hospital Medical Information Network clinical trials registry (UMIN000045622). Results: The full interim analysis set comprised 71 patients with PID and 47 healthy volunteers. The most common International Union of Immunological Societies PID category was primary antibody deficiency (56.3% of patients). Complications were common, especially recurrent respiratory tract infections (63.4%). Most patients with PID were treated with immunoglobulin replacement therapy (73.2%); 22.4% of these patients had serum immunoglobulin levels <700 mg/dL. Among patients who did not undergo hematopoietic cell transplantation, EQ-5D-5L (n=67) and SF-36 (n=59) Physical and Mental Component Summary scores were significantly lower than in healthy volunteers (p < 0.001). WPAI absenteeism, work productivity loss, and activity impairment scores were significantly lower in 42 working patients with PID than in 37 working healthy volunteers (p < 0.05). Other results indicated that patients with PID experience substantial burdens related to medical visits, expenses, work, and daily activities. Discussion: This interim analysis confirms that patients with PID in Japan have lower HR-QOL and work productivity compared with healthy individuals and experience substantial limitations and burdens in their daily lives.

[Diagnosis and treatment of adult patients with inborn errors of immunity].

Primary immunodeficiency diseases (PID) are caused by abnormalities in molecules involved in the immune system, and there are nearly 500 genes associated with PID. The symptoms are not only susceptibile to infectious diseases but also to autoimmune diseases, malignancies, autoinflammatory diseases, and allergies. Thus, these diseases are considered inborn errors of immunity (IEI) rather than PID. IEI is typically thought to occur in childhood because IEI is associated with a genetic variant, but there are also several adult-onset IEIs. The same 10 warning signs used to diagnose IEI in children are used to diagnose the condition in adults as well, who are then given a definitive genetic diagnosis after a 4-step diagnostic process. In addition to prophylactic antimicrobial agents and immunoglobulin replacement therapy, allogeneic hematopoietic cell transplantation (HCT) is performed as a curative therapy in some patients with IEI. However, in adult patients with IEI, HCT may have to be stopped due to complications. Adult patients with IEI need to be promptly assessed for HCT, and HCT must be done before complications increase.

Severe RAS-Associated Lymphoproliferative Disease Case with Increasing αß Double-Negative T Cells with Atypical Features.

Autoimmune lymphoproliferative syndrome (ALPS) is a disease of lymphocyte homeostasis caused by FAS-mediated apoptotic pathway dysfunction and is characterized by non-malignant lymphoproliferation with an increased number of TCRαß+CD4-CD8- double-negative T cells (αßDNTs). Conversely, RAS-associated leukoproliferative disease (RALD), which is caused by gain-of-functional somatic variants in KRAS or NRAS, is considered a group of diseases with a similar course. Herein, we present a 7-year-old Japanese female of RALD harboring NRAS variant that aggressively progressed to juvenile myelomonocytic leukemia (JMML) with increased αßDNTs. She eventually underwent hematopoietic cell transplantation due to acute respiratory distress which was caused by pulmonary infiltration of JMML blasts. In general, αßDNTs have been remarkably increased in ALPS; however, FAS pathway gene abnormalities were not observed in this case. This case with RALD had repeated shock/pre-shock episodes as the condition progressed. This shock was thought to be caused by the presence of a high number of αßDNTs. The αßDNTs observed in this case revealed high CCR4, CCR6, and CD45RO expressions, which were similar to Th17. These increased Th17-like αßDNTs have triggered the inflammation, resulting in the pathogenesis of shock, because Th17 secretes pro-inflammatory cytokines such as interleukin (IL)-17A and granulocyte-macrophage colony-stimulating factor. The presence of IL-17A-secreting αßDNTs has been reported in systemic lupus erythematosus (SLE) and Sjögren's syndrome. The present case is complicated with SLE, suggesting the involvement of Th17-like αßDNTs in the disease pathogenesis. Examining the characteristics of αßDNTs in RALD, JMML, and ALPS may reveal the pathologies in these cases.

An International Survey of Allogeneic Hematopoietic Cell Transplantation for X-Linked Agammaglobulinemia.

PURPOSE: X-linked agammaglobulinemia (XLA) is an inborn error of immunity caused by variants in Bruton's tyrosine kinase (BTK). XLA patients require lifelong immunoglobulin replacement therapy (IgRT). Only few XLA patients are indicated for allogeneic hematopoietic cell transplantation (HCT) because of severe complications. Accordingly, the published transplantation experience in XLA is minimal. We aimed to collect clinical data of XLA patients who received HCT in an international framework and to establish appropriate transplantation criteria and methods for XLA patients. METHODS: XLA patients were recruited through a questionnaire and a literature review. The data are on patient characteristics and transplantation methods and outcomes. RESULTS: In this study, twenty-two XLA patients who underwent HCT were recruited. The indication for HCT was recurrent or life-threatening infection in sixteen patients, malignancy in three, and other factors in three. A myeloablative conditioning, reduced toxicity myeloablative conditioning (RT-MAC), and reduced intensity conditioning (RIC) were selected in four, ten, and eight patients, respectively. Engraftment was achieved in 21 patients (95%). In all patients, 2-year overall survival (OS) and event-free survival (EFS) were 86% and 77%, respectively. In patients who received RT-MAC or RIC using treosulfan, busulfan, or melphalan, 2-year OS and EFS were 82% and 71%, respectively. Finally, twenty-one patients (95%) obtained complete or stable high-level mixed chimerism (50-95%), and the 1-year discontinuation rate of IgRT was 89%. CONCLUSION: Based on the concept in which IgRT is the standard treatment for XLA, HCT may be an effective and safe alternative treatment option for XLA patients, and IgRT can be discontinued following transplantation. It is ideal to perform HCT in XLA patients for whom transplantation is indicated before they develop organ damage.