The HyperPed-COVID international registry: Impact of age of onset, disease presentation and geographical distribution on the final outcome of MIS-C.

OBJECTIVES: The aim of the study was to establish an international multicenter registry to collect data on patients with Multisystem Inflammatory Syndrome in Children (MIS-C), in order to highlight a relationship between clinical presentation, age of onset and geographical distribution on the clinical outcome. STUDY DESIGN: Multicenter retrospective study involving different international societies for rare immunological disorders.1009 patients diagnosed with MIS-C between March and September 2022, from 48 centers and 22 countries were collected. Five age groups (<1, 1-4, 5-11, 12-16, >16 years) and four geographic macro-areas, Western Europe, Central-Eastern Europe, Latin America, Asian-African resource-limited countries (LRC), were identified. RESULTS: Time to referral was significantly higher in LRC. Intensive anti-inflammatory treatment, including biologics, respiratory support and mechanic ventilation were more frequently used in older children and in European countries. The mortality rate was higher in very young children (<1 year), in older patients (>16 years of age) and in LRC. Multivariate analysis identified the residence in LRC, presence of severe cardiac involvement, renal hypertension, lymphopenia and non-use of heparin prophylaxis, as the factors most strongly associated with unfavorable outcomes. CONCLUSIONS: The stratification of patients by age and geographic macro-area provided insights into the clinical presentation, treatment and outcome of MIS-C. The mortality and sequelae rates exhibited a correlation with the age and geographical areas. Patients admitted and treated in LRC displayed more severe outcomes, possibly due to delays in hospital admission and limited access to biologic drugs and to intensive care facilities.

Disease flares with baricitinib dose reductions and development of flare criteria in patients with CANDLE/PRAAS.

OBJECTIVES: Patients with chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature/proteasome-associated autoinflammatory syndrome (CANDLE/PRAAS) respond to the janus kinase inhibitor 1/2 inhibition with baricitinib at exposures higher than in rheumatoid arthritis. Baricitinib dose reductions to minimise exposure triggered disease flares which we used to develop 'flare criteria'. METHODS: Of 10 patients with CANDLE/PRAAS treated with baricitinib in an open-label expanded-access programme, baricitinib doses were reduced 14 times in 9 patients between April 2014 and December 2019. Retrospective data analysis of daily diary scores and laboratory markers collected before and after the dose reductions were used to develop 'clinical' and 'subclinical' flare criteria. Disease flare rates were compared among patients with <25% and >25% dose reductions and during study visits when patients received recommended 'optimized' baricitinib doses (high-dose visits) versus lower than recommended baricitinib doses (low-dose visits) using two-sided χ2 tests. RESULTS: In the 9/10 patients with CANDLE with dose reduction, 7/14 (50%) times the dose was reduced resulted in a disease flare. All four dose reductions of >25% triggered a disease flare (p <0.05). Assessment of clinical and laboratory changes during disease flares allowed the development of disease flare criteria that were assessed during visits when patients received high or low doses of baricitinib. Disease flare criteria were reached during 43.14% of low-dose visits compared with 12.75% of high-dose visits (p <0.0001). Addition of an interferon score as an additional flare criterion increased the sensitivity to detect disease flares. CONCLUSION: We observed disease flares and rebound inflammation with baricitinib dose reductions and proposed flare criteria that can assist in monitoring disease activity and in designing clinical studies in CANDLE/PRAAS.

Case Report: ISG15 deficiency caused by novel variants in two families and effective treatment with Janus kinase inhibition.

ISG15 deficiency is a rare disease caused by autosomal recessive variants in the ISG15 gene, which encodes the ISG15 protein. The ISG15 protein plays a dual role in both the type I and II interferon (IFN) immune pathways. Extracellularly, the ISG15 protein is essential for IFN-γ-dependent anti-mycobacterial immunity, while intracellularly, ISG15 is necessary for USP18-mediated downregulation of IFN-α/ß signalling. Due to this dual role, ISG15 deficiency can present with various clinical phenotypes, ranging from susceptibility to mycobacterial infection to autoinflammation characterised by necrotising skin lesions, intracerebral calcification, and pulmonary involvement. In this report, we describe novel variants found in two different families that result in complete ISG15 deficiency and severe skin ulceration. Whole exome sequencing identified a heterozygous missense p.Q16X ISG15 variant and a heterozygous multigene 1p36.33 deletion in the proband from the first family. In the second family, a homozygous total ISG15 gene deletion was detected in two siblings. We also conducted further analysis, including characterisation of cytokine dysregulation, interferon-stimulated gene expression, and p-STAT1 activation in lymphocytes and lesional tissue. Finally, we demonstrate the complete and rapid resolution of clinical symptoms associated with ISG15 deficiency in one sibling from the second family following treatment with the Janus kinase (JAK) inhibitor baricitinib.

Genetic testing of Behçet's disease using next-generation sequencing to identify monogenic mimics and HLA-B*51.

OBJECTIVE: Several monogenic autoinflammatory disorders and primary immunodeficiencies can present early in life with features that may be mistaken for Behçet's disease (BD). We aimed to develop a genetic analysis workflow to identify rare monogenic BD-like diseases and establish the contribution of HLA haplotype in a cohort of patients from the UK. METHODS: Patients with clinically suspected BD were recruited from four BD specialist care centres in the UK. All participants underwent whole exome sequencing (WES), and genetic analysis thereafter by 1. examining genes known to cause monogenic immunodeficiency, autoinflammation or vasculitis by virtual panel application; 2. scrutiny of variants prioritised by Exomiser using Human Phenotype Ontology (HPO); 3. identification of copy number variants using ExomeDepth; and 4. HLA-typing using OptiType. RESULTS: Thirty-one patients were recruited: median age 15 (4-52), and median disease onset age 5 (0-20). Nine/31 (29%) patients had monogenic disease mimicking BD: 5 cases of Haploinsufficiency of A20 with novel TNFAIP3 variants (p.T76I, p.M112Tfs*8, p.S548Dfs*128, p.C657Vfs*14, p.E661Nfs*36); 1 case of ISG15 deficiency with a novel nonsense variant (ISG15:p.Q16X) and 1p36.33 microdeletion; 1 case of Common variable immune deficiency (TNFRSF13B:p.A181E); and 2 cases of TNF receptor associated periodic syndrome (TNFRSF1A:p.R92Q). Of the remaining 22 patients, 8 (36%) were HLA-B*51 positive. CONCLUSION: We describe a novel genetic workflow for BD, which can efficiently detect known and potentially novel monogenic forms of BD, whilst additionally providing HLA-typing. Our results highlight the importance of genetic testing before BD diagnosis, since this has impact on choice of therapy, prognosis, and genetic counselling.

Validation of the PEDiatric Behçet's Disease classification criteria: an evidence-based approach.

OBJECTIVES: to validate the PEDiatric Behçet's Disease classification criteria (PEDBD) with an evidence-based approach. METHODS: 210 pediatric patients (70 Behçet's disease (BD), 40 Periodic Fever, Aphthous stomatitis, Pharyngitis, Adenitis, 35 familial Mediterranean fever, 26 hyper-IgD syndrome, 22 TNF-Receptor associated Periodic fever Syndrome, 17 undefined recurrent fevers) were randomly selected from the Eurofever Registry. A set of 11 experienced clinicians/researchers blinded to the original diagnosis evaluated the patients. Using the table consensus as gold standard (agreement ≥ 80%), the PEDBD, ISG and ICBD criteria were applied to BD patients and to confounding diseases with other autoinflammatory conditions in order to define their sensitivity, specificity and accuracy. RESULTS: At the end of the third round, a consensus was reached in 139/210 patients (66.2%). The patients with a consensus ≥80% were classified as confirmed-BD (n = 24), and those with an agreement of 60-79% as probable-BD (n = 10). When comparing these patients with the confounding diseases group, an older age at disease onset, the presence of oral and genital ulcers, skin papulo-pustular lesions, a positive pathergy test and posterior uveitis were BD distinctive elements. The ISG, ICBD and PEDBD criteria were applied to confirmed-BD and to the confounding disease group, showing a sensitivity of 0.50, 0.79 and 0.58, a specificity of 1.00, 0.97, 0.99, and an accuracy of 0.91, 0.94 and 0.92, respectively. CONCLUSIONS: the PEDBD criteria were very specific, while the ICBD resulted to be more sensitive. The complexity of childhood BD suggests larger prospective international cohorts to further evaluate the performance of the criteria.

Curation and expansion of the Human Phenotype Ontology for systemic autoinflammatory diseases improves phenotype-driven disease-matching.

Introduction: Accurate and standardized phenotypic descriptions are essential in diagnosing rare diseases and discovering new diseases, and the Human Phenotype Ontology (HPO) system was developed to provide a rich collection of hierarchical phenotypic descriptions. However, although the HPO terms for inborn errors of immunity have been improved and curated, it has not been investigated whether this curation improves the diagnosis of systemic autoinflammatory disease (SAID) patients. Here, we aimed to study if improved HPO annotation for SAIDs enhanced SAID identification and to demonstrate the potential of phenotype-driven genome diagnostics using curated HPO terms for SAIDs. Methods: We collected HPO terms from 98 genetically confirmed SAID patients across eight different European SAID expertise centers and used the LIRICAL (Likelihood Ratio Interpretation of Clinical Abnormalities) computational algorithm to estimate the effect of HPO curation on the prioritization of the correct SAID for each patient. Results: Our results show that the percentage of correct diagnoses increased from 66% to 86% and that the number of diagnoses with the highest ranking increased from 38 to 45. In a further pilot study, curation also improved HPO-based whole-exome sequencing (WES) analysis, diagnosing 10/12 patients before and 12/12 after curation. In addition, the average number of candidate diseases that needed to be interpreted decreased from 35 to 2. Discussion: This study demonstrates that curation of HPO terms can increase identification of the correct diagnosis, emphasizing the high potential of HPO-based genome diagnostics for SAIDs.

Neuroinflammation, autoinflammation, splenomegaly and anemia caused by bi-allelic mutations in IRAK4.

We describe a novel, severe autoinflammatory syndrome characterized by neuroinflammation, systemic autoinflammation, splenomegaly, and anemia (NASA) caused by bi-allelic mutations in IRAK4. IRAK-4 is a serine/threonine kinase with a pivotal role in innate immune signaling from toll-like receptors and production of pro-inflammatory cytokines. In humans, bi-allelic mutations in IRAK4 result in IRAK-4 deficiency and increased susceptibility to pyogenic bacterial infections, but autoinflammation has never been described. We describe 5 affected patients from 2 unrelated families with compound heterozygous mutations in IRAK4 (c.C877T (p.Q293*)/c.G958T (p.D320Y); and c.A86C (p.Q29P)/c.161 + 1G>A) resulting in severe systemic autoinflammation, massive splenomegaly and severe transfusion dependent anemia and, in 3/5 cases, severe neuroinflammation and seizures. IRAK-4 protein expression was reduced in peripheral blood mononuclear cells (PBMC) in affected patients. Immunological analysis demonstrated elevated serum tumor necrosis factor (TNF), interleukin (IL) 1 beta (IL-1ß), IL-6, IL-8, interferon α2a (IFN-α2a), and interferon ß (IFN-ß); and elevated cerebrospinal fluid (CSF) IL-6 without elevation of CSF IFN-α despite perturbed interferon gene signature. Mutations were located within the death domain (DD; p.Q29P and splice site mutation c.161 + 1G>A) and kinase domain (p.Q293*/p.D320Y) of IRAK-4. Structure-based modeling of the DD mutation p.Q29P showed alteration in the alignment of a loop within the DD with loss of contact distance and hydrogen bond interactions with IRAK-1/2 within the myddosome complex. The kinase domain mutation p.D320Y was predicted to stabilize interactions within the kinase active site. While precise mechanisms of autoinflammation in NASA remain uncertain, we speculate that loss of negative regulation of IRAK-4 and IRAK-1; dysregulation of myddosome assembly and disassembly; or kinase active site instability may drive dysregulated IL-6 and TNF production. Blockade of IL-6 resulted in immediate and complete amelioration of systemic autoinflammation and anemia in all 5 patients treated; however, neuroinflammation has, so far proven recalcitrant to IL-6 blockade and the janus kinase (JAK) inhibitor baricitinib, likely due to lack of central nervous system penetration of both drugs. We therefore highlight that bi-allelic mutation in IRAK4 may be associated with a severe and complex autoinflammatory and neuroinflammatory phenotype that we have called NASA (neuroinflammation, autoinflammation, splenomegaly and anemia), in addition to immunodeficiency in humans.

Case report: marfan syndrome (MFS) mimicking cutaneous vasculitis.

Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder caused by variants in the extracellular microfibril fibrillin (FBN1) gene. Here we report an FBN1 variant in a child with an unusual skin rash mimicking cutaneous vasculitis, and mild aortic root dilatation. The case was complicated by lack of typical skeletal MFS phenotype; and severe needle phobia preventing any blood testing for workup of suspected vasculitis. Therefore inflammatory markers, autoantibody profile and general hematology/biochemistry results were unknown. Diagnosis of MFS was made via genetic testing of a saliva sample alone using a next-generation sequencing (NGS) targeted gene panel designed to screen for monogenic forms of vasculitis and noninflammatory vasculopathic mimics. This revealed the patient was heterozygous for a pathogenic frameshift variant in FBN1; NM_000138, c.1211delC, p.(Pro404Hisfs*44), predicted to cause premature protein truncation leading to loss of function. The variant has not been detected in control populations and has previously been detected in individuals with MFS. This rapid diagnosis significantly impacted the patient management: avoidance of invasive investigations; avoidance of unnecessary immunosuppression; facilitating genetic counselling of the index case and family; and directly informing lifelong monitoring and ongoing treatment for aortic root involvement from MFS. This case further emphasizes the diagnostic utility of NGS early in the diagnostic workup of paediatric patients referred with suspected vasculitis, and we emphasize that MFS can present with cutaneous vasculitic-like features in the absence of the typical Marfanoid skeletal phenotype.

Evaluation and Management of Deficiency of Adenosine Deaminase 2: An International Consensus Statement.

Importance: Deficiency of adenosine deaminase 2 (DADA2) is a recessively inherited disease characterized by systemic vasculitis, early-onset stroke, bone marrow failure, and/or immunodeficiency affecting both children and adults. DADA2 is among the more common monogenic autoinflammatory diseases, with an estimate of more than 35 000 cases worldwide, but currently, there are no guidelines for diagnostic evaluation or management. Objective: To review the available evidence and develop multidisciplinary consensus statements for the evaluation and management of DADA2. Evidence Review: The DADA2 Consensus Committee developed research questions based on data collected from the International Meetings on DADA2 organized by the DADA2 Foundation in 2016, 2018, and 2020. A comprehensive literature review was performed for articles published prior to 2022. Thirty-two consensus statements were generated using a modified Delphi process, and evidence was graded using the Oxford Center for Evidence-Based Medicine Levels of Evidence. Findings: The DADA2 Consensus Committee, comprising 3 patient representatives and 35 international experts from 18 countries, developed consensus statements for (1) diagnostic testing, (2) screening, (3) clinical and laboratory evaluation, and (4) management of DADA2 based on disease phenotype. Additional consensus statements related to the evaluation and treatment of individuals with DADA2 who are presymptomatic and carriers were generated. Areas with insufficient evidence were identified, and questions for future research were outlined. Conclusions and Relevance: DADA2 is a potentially fatal disease that requires early diagnosis and treatment. By summarizing key evidence and expert opinions, these consensus statements provide a framework to facilitate diagnostic evaluation and management of DADA2.

Constitutively active Lyn kinase causes a cutaneous small vessel vasculitis and liver fibrosis syndrome.

Neutrophilic inflammation is a hallmark of many monogenic autoinflammatory diseases; pathomechanisms that regulate extravasation of damaging immune cells into surrounding tissues are poorly understood. Here we identified three unrelated boys with perinatal-onset of neutrophilic cutaneous small vessel vasculitis and systemic inflammation. Two patients developed liver fibrosis in their first year of life. Next-generation sequencing identified two de novo truncating variants in the Src-family tyrosine kinase, LYN, p.Y508*, p.Q507* and a de novo missense variant, p.Y508F, that result in constitutive activation of Lyn kinase. Functional studies revealed increased expression of ICAM-1 on induced patient-derived endothelial cells (iECs) and of ß2-integrins on patient neutrophils that increase neutrophil adhesion and vascular transendothelial migration (TEM). Treatment with TNF inhibition improved systemic inflammation; and liver fibrosis resolved on treatment with the Src kinase inhibitor dasatinib. Our findings reveal a critical role for Lyn kinase in modulating inflammatory signals, regulating microvascular permeability and neutrophil recruitment, and in promoting hepatic fibrosis.

Efficacy and safety of emapalumab in macrophage activation syndrome.

OBJECTIVES: Macrophage activation syndrome (MAS) is a severe, life-threatening complication of systemic juvenile idiopathic arthritis (sJIA) and adult-onset Still's disease (AOSD). The objective of this study was to confirm the adequacy of an emapalumab dosing regimen in relation to interferon-γ (IFNγ) activity by assessing efficacy and safety. The efficacy outcome was MAS remission by week 8, based on clinical and laboratory criteria. METHODS: We studied emapalumab, a human anti-IFNγ antibody, administered with background glucocorticoids, in a prospective single-arm trial involving patients who had MAS secondary to sJIA or AOSD and had previously failed high-dose glucocorticoids, with or without anakinra and/or ciclosporin. The study foresaw 4-week treatment that could be shortened or prolonged based on investigator's assessment of response. Patients entered a long-term (12 months) follow-up study. RESULTS: Fourteen patients received emapalumab. All patients completed the trial, entered the long-term follow-up and were alive at the end of follow-up. The investigated dosing regimen, based on an initial loading dose followed by maintenance doses, was appropriate, as shown by rapid neutralisation of IFNγ activity, demonstrated by a prompt decrease in serum C-X-C motif chemokine ligand 9 (CXCL9) levels. By week 8, MAS remission was achieved in 13 of the 14 patients at a median time of 25 days. Viral infections and positive viral tests were observed. CONCLUSIONS: Neutralisation of IFNγ with emapalumab was efficacious in inducing remission of MAS secondary to sJIA or AOSD in patients who had failed high-dose glucocorticoids. Screening for viral infections should be performed, particularly for cytomegalovirus. TRIAL REGISTRATION NUMBER: NCT02069899 and NCT03311854.

Multi-centre, randomised, open-label, blinded endpoint assessed, trial of corticosteroids plus intravenous immunoglobulin (IVIG) and aspirin, versus IVIG and aspirin for prevention of coronary artery aneurysms (CAA) in Kawasaki disease (KD): the KD CAA prevention (KD-CAAP) trial protocol.

BACKGROUND: Kawasaki disease (KD) is an acute self-limiting inflammatory vasculitis affecting predominantly medium-sized arteries, particularly the coronary arteries. A number of recent studies conducted in different European countries have demonstrated alarmingly high coronary complications despite treatment with intravenous immunoglobulin (IVIG). These high complication rates now emphasize the need for an urgent reappraisal of IVIG as the sole primary therapeutic agent for KD. The Kawasaki disease CAA prevention (KD-CAAP) trial will test the hypothesis that immediate adjunctive corticosteroid treatment to standard of care IVIG and aspirin will reduce coronary artery aneurysm (CAA) rates in unselected KD patients across Europe. METHODS: KD-CAAP is a multicentre, randomised, controlled, open-label, blinded endpoint assessed trial that will be conducted across Europe supported by the conect4children pan-European clinical trials network. Patients with KD who satisfy the eligibility criteria will be randomised (1:1) to receive either oral prednisolone 2 mg/kg/day plus standard of care therapy IVIG (2 g/kg) and aspirin (40 mg/kg/day); or IVIG and aspirin alone. Further management is dictated by temperature and C-reactive protein (CRP) responses. Co-primary outcomes are as follows: (i) any CAA within the 3 months of trial follow-up; (ii) average estimate of maximum coronary Z-score at weeks 1, 2 and 6 adjusting for rescue treatment. Additional outcomes will be assessed including cost effectiveness, quality of life, corticosteroid toxicity and other safety outcomes. DISCUSSION: Several recent studies have indicated that coronary complications associated with KD across Europe are much higher than early trials of IVIG had initially suggested. KD-CAAP directly addresses this issue by exploring the therapeutic benefit of adjunctive corticosteroids in unselected KD cases. If we find that corticosteroids prevent CAA and are safe, this is a cheap and widely available intervention that could be implemented immediately for the benefit of children. TRIAL REGISTRATION: ISRCTN71987471- March 31, 2020; Eudract 2019-004433-17.

The incidence of Kawasaki disease using hospital admissions data for England 2006-2021.

OBJECTIVE: To describe the incidence of Kawasaki Disease (kDa) between 2006 and 2021 in England. METHODS: We identified all cases in hospital episode statistics with an ICD-10 diagnostic code M303 (for kDa) between 1 April 2006 and 31 March 2021. We validated 83 diagnoses using hospital medical records and found >97% accuracy. We calculated incidence rate ratios (IRRs) using Poisson regression and assessed the influence of age, sex, ethnicity and index of multiple deprivation (IMD). We used Office for National Statistics population estimates for England as the denominator. RESULTS: We identified a total of 5908 cases of kDa in all children under the age of 16 (mean age 3.8, s.d.=3.2, 95% CI: 3.7, 3.9). Incidence in children aged <5 years was 8.9 (95% CI: 8.6, 9.2)/100 000 person-years; in children aged 5-9, 2.4 (95% CI: 2.3, 2.6)/100 000 person-years; and in children aged 10-15, 0.6 (95% CI: 0.6, 0.7). Male : female ratio was 1.5 : 1. Incidence was higher among non-White than White ethnicities [adjusted IRR 2.1 (2.0-2.2) for Asian, 3.0 (2.8-3.3) for Black and 4.5 (4.2-4.8) for other ethnicities]. The incidence increased with socioeconomic deprivation; the adjusted IRR of the least deprived IMD quintile compared with the most deprived quintile was 0.81 (0.77-0.84). CONCLUSIONS: Incidence rates of kDa derived from hospital admission data in England were higher than in studies relying on clinician reporting. We confirm previous findings on the influence of sex and ethnicity on kDa incidence and observe that there was a higher incidence of kDa within more deprived socioeconomic groups.

Histiocytoid Sweet Syndrome Presenting in Two Sisters With Deficiency of Deaminase Type 2.

ABSTRACT: Deficiency of adenosine deaminase type 2 (DADA2) is an autosomal recessive monogenic autoinflammatory syndrome that is classically characterised by polyarteritis nodosa, systemic vasculitis and stroke. The spectrum of disease manifestations has broadened to encompass a range of cutaneous, vascular and haematological manifestations. We report a novel association in two sisters with heterozygous p.R169G/p.M309l mutations in ADA2 with low serum ADA2 activity who both presented similarly with clinical and histological features consistent with histiocytoid Sweet syndrome.

A rapid turnaround gene panel for severe autoinflammation: Genetic results within 48 hours.

There is an important unmet clinical need for fast turnaround next generation sequencing (NGS) to aid genetic diagnosis of patients with acute and sometimes catastrophic inflammatory presentations. This is imperative for patients who require precise and targeted treatment to prevent irreparable organ damage or even death. Acute and severe hyper- inflammation may be caused by primary immunodeficiency (PID) with immune dysregulation, or more typical autoinflammatory diseases in the absence of obvious immunodeficiency. Infectious triggers may be present in either immunodeficiency or autoinflammation. We compiled a list of 25 genes causing monogenetic immunological diseases that are notorious for their acute first presentation with fulminant inflammation and which may be amenable to specific treatment, including hemophagocytic lymphohistiocytosis (HLH); and autoinflammatory diseases that can present with early-onset stroke or other irreversible neurological inflammatory complications. We designed and validated a pipeline that enabled return of clinically actionable results in hours rather than weeks: the Rapid Autoinflammation Panel (RAP). We demonstrated accuracy of this new pipeline, with 100% sensitivity and 100% specificity. Return of results to clinicians was achieved within 48-hours from receiving the patient's blood or saliva sample. This approach demonstrates the potential significant diagnostic impact of NGS in acute medicine to facilitate precision medicine and save "life or limb" in these critical situations.

Microvasculopathy in spinal muscular atrophy is driven by a reversible autonomous endothelial cell defect.

Spinal muscular atrophy (SMA) is a neuromuscular disorder due to degeneration of spinal cord motor neurons caused by deficiency of the ubiquitously expressed SMN protein. Here, we present a retinal vascular defect in patients, recapitulated in SMA transgenic mice, driven by failure of angiogenesis and maturation of blood vessels. Importantly, the retinal vascular phenotype was rescued by early, systemic SMN restoration therapy in SMA mice. We also demonstrate in patients an unfavorable imbalance between endothelial injury and repair, as indicated by increased circulating endothelial cell counts and decreased endothelial progenitor cell counts in blood circulation. The cellular markers of endothelial injury were associated with disease severity and improved following SMN restoration treatment in cultured endothelial cells from patients. Finally, we demonstrated autonomous defects in angiogenesis and blood vessel formation, secondary to SMN deficiency in cultured human and mouse endothelial cells, as the underlying cellular mechanism of microvascular pathology. Our cellular and vascular biomarker findings indicate microvasculopathy as a fundamental feature of SMA. Our findings provide mechanistic insights into previously described SMA microvascular complications, and highlight the functional role of SMN in the periphery, including the vascular system, where deficiency of SMN can be addressed by systemic SMN-restoring treatment.

The pediatric glucocorticoid toxicity index.

OBJECTIVES: To develop a Pediatric glucocorticoid toxicity index (pGTI), a standardized, weighted clinical outcome assessment that measures change in glucocorticoid (GC) toxicity over time. METHODS: Fourteen physician experts from 7 subspecialties participated. The physician experts represented multiple subspecialties in which GCs play a major role in the treatment of inflammatory disease: nephrology, rheumatology, oncology, endocrinology, genetics, psychiatry, and maternal-fetal medicine. Nine investigators were from Canada, Europe, or New Zealand, and 5 were from the United States. Group consensus methods and multi-criteria decision analysis were used. The pGTI is an aggregate assessment of GC toxicities that are common, important, and dynamic. These toxicities are organized into health domains graded as minor, moderate, or major and are weighted according to severity. The relative weights were derived by group consensus and multi-criteria decision analysis using the 1000MindsTM software platform. Two quantitative scores comprise the overall toxicity profile derived from pGTI data: (1) the Cumulative Worsening Score; and (2) the Aggregate Improvement Score. The pGTI also includes a qualitative, unweighted record of GC side-effects known as the Damage Checklist, which documents less common toxicities that, although potentially severe, are unlikely to change with varying GC dosing. RESULTS: One hundred and seven (107) toxicity items were included in the pGTI and thirty-two (32) in the Damage Checklist. To assess the degree to which the pGTI corresponds to expert clinical judgement, the investigators ranked 15 cases by clinical judgement from highest to lowest GC toxicity. Expert rankings were then compared to case ranking by the pGTI, yielding excellent agreement (weighted kappa 0.86). The pGTI was migrated to a digital environment following its development and initial validation. The digital platform is designed to ensure ease-of-use in the clinic, rigor in application, and accuracy of scoring. Clinic staff enter vital signs, laboratory results, and medication changes relevant to pGTI scoring. Clinicians record findings for GC myopathy, skin toxicity, mood dysfunction, and infection. The pGTI algorithms then apply the weights to these raw data and calculate scores. Embedded logic accounts for the impact of age- and sex-related reference ranges on several health domains: blood pressure, lipid metabolism, and bone mineral density. Other algorithms account for anticipated changes in the height Z-scores used in the growth domain, thereby addressing a concern unique to GC toxicity in children. The Damage Checklist ensures comprehensive measurement of GC toxicity but does not contribute to pGTI scoring, because the scored domains emphasize manifestations of GC toxicity that are likely to change over the course of a trial. CONCLUSIONS: We describe the development and initial evaluation of a weighted, composite toxicity index for the assessment of morbidity related to GC use in children and adolescents. Developing the pGTI digital platform was essential for performing the nuanced calculations necessary to ensure rigor, accuracy, and ease-of-use in both clinic and research settings.

Lentiviral Mediated ADA2 Gene Transfer Corrects the Defects Associated With Deficiency of Adenosine Deaminase Type 2.

Deficiency of adenosine deaminase type 2 (DADA2) is an autosomal recessive disease caused by bi-allelic loss-of-function mutations in ADA2. Treatment with anti-TNF is effective for the autoinflammatory and vasculitic components of the disease but does not correct marrow failure or immunodeficiency; and anti-drug antibodies cause loss of efficacy over time. Allogeneic haematopoietic stem cell transplantation may be curative, but graft versus host disease remains a significant concern. Autologous gene therapy would therefore be an attractive longer-term therapeutic option. We investigated whether lentiviral vector (LV)-mediated ADA2 gene correction could rescue the immunophenotype of DADA2 in primary immune cells derived from patients and in cell line models. Lentiviral transduction led to: i) restoration of ADA2 protein expression and enzymatic activity; (ii) amelioration of M1 macrophage cytokine production, IFN-γ and phosphorylated STAT1 expression in patient-derived macrophages; and (iii) amelioration of macrophage-mediated endothelial activation that drives the vasculitis of DADA2. We also successfully transduced human CD34+ haematopoietic stem progenitor cells (HSPC) derived from a DADA2 patient with pure red cell aplasia and observed restoration of ADA2 expression and enzymatic activity in CD34+HSPC, alongside recovery of stem-cell proliferative and colony forming unit capacity. These preclinical data now expand the evidence for the efficacy of gene transfer strategies in DADA2, and strongly support clinical translation of a lentivirus-mediated gene therapy approach to treat DADA2.