Gain-of-function human UNC93B1 variants cause systemic lupus erythematosus and chilblain lupus.

UNC93B1 is a transmembrane domain protein mediating the signaling of endosomal Toll-like receptors (TLRs). We report five families harboring rare missense substitutions (I317M, G325C, L330R, R466S, and R525P) in UNC93B1 causing systemic lupus erythematosus (SLE) or chilblain lupus (CBL) as either autosomal dominant or autosomal recessive traits. As for a D34A mutation causing murine lupus, we recorded a gain of TLR7 and, to a lesser extent, TLR8 activity with the I317M (in vitro) and G325C (in vitro and ex vivo) variants in the context of SLE. Contrastingly, in three families segregating CBL, the L330R, R466S, and R525P variants were isomorphic with respect to TLR7 activity in vitro and, for R525P, ex vivo. Rather, these variants demonstrated a gain of TLR8 activity. We observed enhanced interaction of the G325C, L330R, and R466S variants with TLR8, but not the R525P substitution, indicating different disease mechanisms. Overall, these observations suggest that UNC93B1 mutations cause monogenic SLE or CBL due to differentially enhanced TLR7 and TLR8 signaling.

Comparison of incidence, causes and prognosis of adult and pediatric epidermal necrolysis: a population-based study in France.

BACKGROUND: Epidermal necrolysis (EN), comprising Stevens Johnson syndrome and toxic epidermal necrolysis is a rare and severe blistering reaction, mainly induced by drugs. Differences have been discussed between pediatric and adult patients regarding incidence, causes, and outcomes, but only based on a limited number of patients, in small case-series. OBJECTIVES: To directly compare incidence, causes and prognosis between adult and pediatric EN patients. METHODS: We used the French Health System Database from January 1st 2013 to December 31st 2022. We included adult and pediatric patients hospitalized for EN using the international classification of diseases, 10th revision codes combined with validated algorithms. The outcomes were incidence of EN; presence of a suspected drug before EN onset, defined by a new drug dispensation from 5 to 56 days before hospitalization; and in-hospital mortality. To estimate the association between pediatric EN and the presence of a suspected drug, we computed a multivariable logistic regression with odd ratios (OR). To estimate the association with mortality, we computed a multivariable Cox proportional hazard ratio (HR) model. RESULTS: A total of 1440 EN patients were included, with 799 (55.5%) females, comprising 219 children and 1221 adults. Among children, EN incidence was 1.5 cases (95%CI: 1.3-1.7) per million people year compared with 2.6 cases (95%CI: 2.5-2.7) in adults. Moreover, children had less chances to have a culprit drug before EN onset (93/219 (42.5%) versus 829/1221 (67.9%)), with an adjusted OR of 0.43 (95%CI: 0.32-0.59), p < 0.0001, together with a better prognosis, with death rates of 1.4% (95%CI: 0.4%-3.7%) in pediatric patients compared with 19.4% (95%CI: 17.3%-21.7%) in adult patients, and an adjusted HR of 0.12 (95%CI: 0.04-0.38), p = 0.0003 for in-hospital mortality. CONCLUSION: Pediatric EN seems to be rarer, with less chances to be caused by drugs, together with a better prognosis than adult EN. These results suggest the existence of different underlying pathophysiological mechanisms and clinical particularities between adult and pediatric patients.

Exploring the Impact of Epidermolysis Bullosa on Parents and Caregivers: A Cross-Cultural Validation of the Epidermolysis Bullosa Burden of Disease Questionnaire.

Purpose: Epidermolysis bullosa (EB) is a heterogeneous group of genetically inherited skin and mucosal fragility disorders. EB may have a profound impact on parental physical and psychosocial health. This study was designed to evaluate the disease burden in parents of patients with EB and identify out-of-pocket (OOP) expenditures for EB care in Saudi Arabia. Patients and Methods: Thirty-eight caregivers of patients with EB were recruited from the Saudi EB registry to participate. All participants completed the EB Burden of Disease (EB-BoD) questionnaire. Data were collected between May 2020 and December 2020. The sample included 10 patients with EB simplex (EBS), 10 with junctional EB (JEB), 14 with dystrophic EB (DEB), and 4 with an unknown type. Results: Mothers were the primary caregivers in 89.5% of cases. The mean EB-BoD score was 53 ± 21.5. The family-life and child's life dimensions had the higher burden. The mean EB-BoD score observed in patients with DEB was 62.4±16.8 versus 45.7 ± 19.42 for EBS. The EB-BoD score was correlated with the patient's family income. Most caregivers (97.4%) reported OOP expenditure, with a mean monthly OOP expenditure of $575.5± $701.1. OOP expenses increased with the severity of the condition. Conclusion: This study highlights the need for support services for parents caring for patients with EB.

"Quality of Life in Epidermolysis Bullosa" and "Epidermolysis Bullosa Burden of Disease": Italian translation, cultural adaptation, and pilot testing of two disease-specific questionnaires.

BACKGROUND: Inherited epidermolysis bullosa (EB) is a clinically and genetically heterogeneous group of skin fragility disorders characterized by blister formation following minor trauma. Four major types are distinguished based on the level of cleavage within the skin. Most EB forms present severely disabling cutaneous and systemic signs and symptoms. Management relies on daily time-consuming and distressing topical medications, and symptomatic treatment of systemic findings. Disease manifestations, symptoms, and daily care strongly affect patient and caregiver quality of life (QoL). To date, there are two validated EB-specific questionnaires, the "Quality of Life in Epidermolysis Bullosa" (QOLEB) and the "Epidermolysis Bullosa Burden of Disease" (EB-BoD) for the evaluation of patient and family disease burden, respectively. The aim of our study was to develop an Italian translation of the two questionnaires and to pilot-test them. METHODS: The guidelines for translation and cross-cultural adaptation of health-related QoL measures were followed. Initially, two separate translations were generated for each questionnaire, and subsequently reconciled by an expert committee. This was followed by a back-translation process. The original texts and all translations underwent revision by the expert committee, resulting in definitive versions. The final versions were then tested in a pilot study involving cognitive debriefing in a group of 17 families, representative of all EB major types. RESULTS: The translation and reconciliation process led to minor changes to obtain semantic/idiomatic/cultural equivalence of the Italian versions with the original ones and to reconcile the questions with the answer options. The cognitive debriefing process showed a good understanding and did not require text modifications. CONCLUSIONS: The Italian versions of the QOLEB and EB-BoD provide valuable tools in everyday clinical practice of reference centers, and they allow the participation in multicenter international real-life observational studies as well as in controlled clinical trials. They enable the identification of disease-specific psychological and socioeconomic challenges for EB patients and their families, guiding targeted interventions to ensure appropriate and timely care.

Drugs associated with epidermal necrolysis in children: A World Health Organization pharmacovigilance database analysis.

BACKGROUND: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare life-threatening mucocutaneous reactions most often induced by drugs. To date, no large pharmacovigilance study has been conducted in the paediatric population. OBJECTIVES: To describe the spectrum of drugs associated with SJS-TEN in children through the analysis of cases reported in the WHO pharmacovigilance database (VigiBase). METHODS: Disproportionality study using data from VigiBase. All paediatric (age under 18 years) cases reported between January 1, 1967, and July 6, 2022, were included. For each molecule, a case-non-case study was performed to assess a potential pharmacovigilance signal by computing the lower end of the 95% credibility interval for the information component (IC025). We performed sensitivity analyses, (i) taking into account only cases reported by physicians and (ii) taking into account only cases reported in the last 10 years. RESULTS: Among 31,376,783 adverse drug reactions reported in VigiBase, 2,248,727 were paediatric cases and 7342 were encoded as paediatric SJS-TEN. Significant statistical pharmacovigilance signals were observed for 165 drugs. The two most represented drug classes were antiepileptics and anti-infectious drugs. The five drugs with the highest IC025 were lamotrigine (IC025 4.99), carbamazepine (IC025 4.88), phenobarbital (IC025 4.67), phenytoin (IC025 4.52) and nimesulide (IC025 4.23). Acetaminophen was significantly associated with paediatric SJS-TEN (IC025 2.85) and we also described various new suspected drugs. Vaccines had no significant pharmacovigilance signal. These results were confirmed with the sensitivity analyses. CONCLUSIONS: This study updates the spectrum of drugs potentially associated with paediatric SJS-TEN.

Ruxolitinib Rescues Multiorgan Clinical Autoimmunity in Patients with APS-1.

Autoimmune polyendocrine syndrome type-1 (APS-1) is caused by mono- or biallelic loss-of-function variants of the autoimmune regulator gene AIRE underlying early-onset multiorgan autoimmunity and the production of neutralizing autoantibodies against cytokines, accounting for mucosal candidiasis and viral diseases. Medical intervention is essential to prevent or attenuate autoimmune manifestations. Ruxolitinib is a JAK inhibitor approved for use in several autoimmune conditions. It is also used off-label to treat autoimmune manifestations of a growing range of inborn errors of immunity. We treated three APS-1 patients with ruxolitinib and followed them for at least 30 months. Tolerance was excellent, with no medical or biological adverse events. All three patients had remarkably positive responses to ruxolitinib for alopecia, nail dystrophy, keratitis, mucosal candidiasis, steroid-dependent autoimmune hepatitis, exocrine pancreatic insufficiency, renal potassium wasting, hypoparathyroidism, and diabetes insipidus. JAK inhibitors were therefore considered an effective treatment in three patients with APS-1. Our observations suggest that JAK/STAT pathways are involved in the pathogenesis of APS-1 autoimmune manifestations. They also suggest that JAK inhibitors should be tested in a broader range of APS-1 patients.

Unclassifiable interstitial lung disease and autoimmunity: Towards IPAF in children?

INTRODUCTION: Interstitial pneumonia with autoimmune features (IPAF) has been defined for adults with interstitial lung disease (ILD) and autoimmunity who do not meet the criteria for a specific connective tissue disease (CTD). We aimed to determine whether IPAF criteria could apply to children. METHODS: We retrospectively studied patients with ILD and autoimmunity followed at Necker Hospital between 2008 and 2019. Children were classified according to specific CTD and IPAF criteria. The epidemiology and course of the disease were studied according to the final diagnosis. RESULTS: Among 27 patients, 6 fulfilled the criteria for IPAF and represented 4.5% of all patients with ILD during the study period. Other diagnoses included juvenile dermatomyositis (30%), overlap syndromes (19%), systemic lupus erythematosus (15%), systemic sclerosis (7%), mixed CTD (4%), and rheumatoid arthritis (4%). IPAF patients were more frequently boys versus CTD-ILD patients (67% vs. 14%, p = .02). Two patients had severe respiratory distress that led to death for one of them. The course was favorable for the others, with a good response to steroids. The course tended to be more favorable for IPAF patients than for those with CTD-ILD (0% lung fibrosis in the IPAF group vs. 43% in the CTD-ILD group, p = .07). CONCLUSION: We confirmed the existence of IPAF in children. Its prevalence was lower than in adults but comparable to that found for other pediatric series. Boys were more highly represented than in CTD-ILD. The course was favorable for most cases. Larger and more prospective studies are needed to confirm these results.

The Ectodermal Dysplasias-Burden of Disease Score: Development and Validation of an Ectodermal Dysplasia Family/Parental Burden Score.

Ectodermal dysplasias are genetic conditions affecting the development and/or homeostasis of 2 or more ectodermal derivatives, including hair, teeth, nails, and certain glands. No tool is available to assess the burden of ectodermal dysplasias and its multidimensional impact on patients and their families. This study developed and validated a familial/parental 19-item burden questionnaire designed specifically for ectodermal dysplasias. Each group of questions was linked to 1 of the following dimensions: (i) Impact of the disease on social life and hobbies; (ii) Future prospects; (iii) Restraint of the disease on outdoor activities; (iv) Financial burden of the disease; (v) Acceptance of the disease. Cronbach's alpha was 0.91 for the entire Ectodermal Dysplasias-Burden of Disease (ED-BD) scale, confirming excellent internal coherence. Intradimensional coherences all demonstrated excellent reliability (α > 0.76). The ED-BD questionnaire was highly correlated with the Short Form-12 and Psychological General Well Being Index validated questionnaires. Cultural and linguistic validation in US English was conducted. Development and validation of the questionnaire was based on data from patients with the 2 main ectodermal dysplasias subtypes. This ED-BD questionnaire represents the first specific assessment tool for evaluating the familial/parental burden of ectodermal dysplasias.

Accurate diagnosis of acute hemorrhagic edema of infancy: a French multicenter observational study.

The purpose of the study is to highlight clinical signs that are either suggestive of or against the diagnosis of AHEI to improve diagnosis and management. The medical records of children under 3 years old diagnosed with AHEI were retrospectively reviewed. Clinical data and photographs were reviewed by three independent experts, and the cases were classified as probable, doubtful, or unclear AHEI. Of the 69 cases of children diagnosed with AHEI included in 22 centers, 40 were classified as probable, 22 as doubtful, and 7 as unclear. The median age of patients with probable AHEI was 11 months [IQR 9-15], and they were in overall good condition (n = 33/40, 82.5%). The morphology of the purpura was targetoid in 75% of cases (n = 30/40) and ecchymotic in 70% of cases (n = 28/40) and affected mostly the legs (n = 39/40, 97%), the arms (n = 34/40, 85%), and the face (n = 33/40, 82.5%). Edema was observed in 95% of cases and affected mostly the hands (n = 36/38, 95%) and feet (n = 28/38, 74%). Pruritus was absent in all patients with probable AHEI and described for 6/21 with doubtful AHEI (29%). AHEI was the original diagnosis in only 24 patients (n = 24/40, 60%). The major differential diagnoses were purpura fulminans and urticaria multiforme.  Conclusion: AHEI, which the diagnosis is made on clinical findings, is often misdiagnosed. Purpuric lesions localized on the face/ears, arms/forearms, and thighs/legs with edema of the hands without pruritus in a young child with a good overall condition are highly suggestive of AHEI. What is Known: •Acute hemorrhagic edema of infancy (AHEI) is a cutaneous leukocytoclastic vasculitis affecting children under 3 years old. •Appropriate diagnosis is important to distinguish this benign disease from more serious diseases to avoid investigations and treatments, iatrogenic harm and unnecessary follow-up. What is New: •AHEI is an uncommon disorder often misdiagnosed by pediatricians and dermatologists. •Purpuric lesions localized on the face/ears, arms/forearms, and thighs/legs with edema of the hands without pruritus in an infant with a good overall condition are highly suggestive of AHEI.

JAK Inhibition in Aicardi-Goutières Syndrome: a Monocentric Multidisciplinary Real-World Approach Study.

The paradigm type I interferonopathy Aicardi-Goutières syndrome (AGS) is most typically characterized by severe neurological involvement. AGS is considered an immune-mediated disease, poorly responsive to conventional immunosuppression. Premised on a chronic enhancement of type I interferon signaling, JAK1/2 inhibition has been trialed in AGS, with clear improvements in cutaneous and systemic disease manifestations. Contrastingly, treatment efficacy at the level of the neurological system has been less conclusive. Here, we report our real-word approach study of JAK1/2 inhibition in 11 patients with AGS, providing extensive assessments of clinical and radiological status; interferon signaling, including in cerebrospinal fluid (CSF); and drug concentrations in blood and CSF. Over a median follow-up of 17 months, we observed a clear benefit of JAK1/2 inhibition on certain systemic features of AGS, and reproduced results reported using the AGS neurologic severity scale. In contrast, there was no change in other scales assessing neurological status; using the caregiver scale, only patient comfort, but no other domain of everyday-life care, was improved. Serious bacterial infections occurred in 4 out of the 11 patients. Overall, our data lead us to conclude that other approaches to treatment are urgently required for the neurologic features of AGS. We suggest that earlier diagnosis and adequate central nervous system penetration likely remain the major factors determining the efficacy of therapy in preventing irreversible brain damage, implying the importance of early and rapid genetic testing and the consideration of intrathecal drug delivery.

Molecular and clinicopathologic characterization of pediatric histiocytoses.

The spectrum of somatic mutations in pediatric histiocytoses and their clinical implications are not fully characterized, especially for non-Langerhans cell histiocytosis (-LCH) subtypes. A cohort of 415 children with histiocytosis from the French histiocytosis registry was reviewed and analyzed for BRAFV600E . Most BRAFWT samples were analyzed by next-generation sequencing (NGS) with a custom panel of genes for histiocytosis and myeloid neoplasia. Of 415 case samples, there were 366 LCH, 1 Erdheim-Chester disease, 21 Rosai-Dorfman disease (RDD), 21 juvenile xanthogranuloma (JXG, mostly with severe presentation), and 6 malignant histiocytosis (MH). BRAFV600E was the most common mutation found in LCH (50.3%, n = 184). Among 105 non-BRAFV600E -mutated LCH case samples, NGS revealed mutations as follows: MAP2K1 (n = 44), BRAF exon 12 deletions (n = 26), and duplications (n = 8), other BRAF V600 codon mutation (n = 4), and non-MAP-kinase pathway genes (n = 5). Wild-type sequences were identified in 17.1% of samples. BRAFV600E was the only variant significantly correlated with critical presentations: organ-risk involvement and neurodegeneration. MAP-kinase pathway mutations were identified in seven RDD (mostly MAP2K1) and three JXG samples, but most samples were wild-type on NGS. Finally, two MH samples had KRAS mutations, and one had a novel BRAFG469R mutation. Rarely, we identified mutations unrelated to MAP-kinase pathway genes. In conclusion, we characterized the mutational spectrum of childhood LCH and clinical correlations of variants and subtypes. Variants responsible for JXG and RDD were not elucidated in more than half of the cases, calling for other sequencing approaches.

Ocular sequelae of epidermal necrolysis: French national audit of practices, literature review and proposed management.

Stevens-Johnson Syndrome (SJS) and toxic epidermal necrolysis (TEN) are serious and rare diseases, most often drug-induced, and their incidence has been estimated at 6 cases/million/year in France. SJS and TEN belong to the same spectrum of disease known as epidermal necrolysis (EN). They are characterized by more or less extensive epidermal detachment, associated with mucous membrane involvement, and may be complicated during the acute phase by fatal multiorgan failure. SJS and TEN can lead to severe ophthalmologic sequelae. There are no recommendations for ocular management during the chronic phase. We conducted a national audit of current practice in the 11 sites of the French reference center for toxic bullous dermatoses and a review of the literature to establish therapeutic consensus guidelines. Ophthalmologists and dermatologists from the French reference center for epidermal necrolysis were asked to complete a questionnaire on management practices in the chronic phase of SJS/TEN. The survey focused on the presence of a referent ophthalmologist at the center, the use of local treatments (artificial tears, corticosteroid eye drops, antibiotic-corticosteroids, antiseptics, vitamin A ointment (VA), cyclosporine, tacrolimus), the management of trichiatic eyelashes, meibomian dysfunction, symblepharons, and corneal neovascularization, as well as the contactologic solutions implemented. Eleven ophthalmologists and 9 dermatologists from 9 of the 11 centers responded to the questionnaire. Based on questionnaire results, 10/11 ophthalmologists systematically prescribed preservative-free artificial tears, and 11/11 administered VA. Antiseptic or antibiotic eye drops or antibiotic-corticosteroid eye drops were recommended as needed by 8/11 and 7/11 ophthalmologists, respectively. In case of chronic inflammation, topical cyclosporine was consistently proposed by 11/11 ophthalmologists. The removal of trichiatic eyelashes was mainly performed by 10/11 ophthalmologists. Patients were referred to a reference center for fitting of scleral lenses (10/10,100%). Based on this practice audit and literature review, we propose an evaluation form to facilitate ophthalmic data collection in the chronic phase of EN and we also propose an algorithm for the ophthalmologic management of ocular sequelae.

DOCK11 deficiency in patients with X-linked actinopathy and autoimmunity.

Dedicator of cytokinesis (DOCK) proteins play a central role in actin cytoskeleton regulation. This is highlighted by the DOCK2 and DOCK8 deficiencies leading to actinopathies and immune deficiencies. DOCK8 and DOCK11 activate CDC42, a Rho-guanosine triphosphate hydrolases involved in actin cytoskeleton dynamics, among many cellular functions. The role of DOCK11 in human immune disease has been long suspected but, to the best of our knowledge, has never been described to date. We studied 8 male patients, from 7 unrelated families, with hemizygous DOCK11 missense variants leading to reduced DOCK11 expression. The patients were presenting with early-onset autoimmunity, including cytopenia, systemic lupus erythematosus, skin, and digestive manifestations. Patients' platelets exhibited abnormal ultrastructural morphology and spreading as well as impaired CDC42 activity. In vitro activated T cells and B-lymphoblastoid cell lines from patients exhibited aberrant protrusions and abnormal migration speed in confined channels concomitant with altered actin polymerization during migration. Knock down of DOCK11 recapitulated these abnormal cellular phenotypes in monocytes-derived dendritic cells and primary activated T cells from healthy controls. Lastly, in line with the patients' autoimmune manifestations, we also observed abnormal regulatory T-cell (Treg) phenotype with profoundly reduced FOXP3 and IKZF2 expression. Moreover, we found reduced T-cell proliferation and impaired STAT5B phosphorylation upon interleukin-2 stimulation of the patients' lymphocytes. In conclusion, DOCK11 deficiency is a new X-linked immune-related actinopathy leading to impaired CDC42 activity and STAT5 activation, and is associated with abnormal actin cytoskeleton remodeling as well as Treg phenotype, culminating in immune dysregulation and severe early-onset autoimmunity.