The 2021 EULAR and ACR points to consider for diagnosis and management of autoinflammatory type I interferonopathies: CANDLE/PRAAS, SAVI and AGS

Interferonopathies: From concept to clinical practice

The horror autoinflammaticus derived from aberrant type I interferon secretion determines a special group of autoinflammatory diseases named interferonopathies. Diverse mechanisms involved in nucleic acids sensing, metabolizing or the lack of interferon signaling retro-control are responsible for the phenotypes associated to Aicardi-Goutières Syndrome (AGS), Proteasome-Associated Autoinflammatory Diseases (PRAAS), STING-Associated Vasculopathy with Infancy Onset (SAVI) and certain forms of monogenic Systemic lupus erythematosus (SLE). This review approaches interferonopathies from the basic immunogenetic concept to diagnosis and treatment.

The autoimmune landscape of Porto-sinusoidal vascular disorder: What the rheumatologist needs to know

Porto-sinusoidal vascular disorder (PSVD) encompasses a group of vascular disorders characterized by lesions of the portal venules and sinusoids with clinical manifestations ranging from non-specific abnormalities in serum liver enzymes to clinically overt portal hypertension and related complications. Several reports have documented cases of PSVD in patients with systemic autoimmune conditions, such as systemic lupus erythematosus, systemic sclerosis, and rheumatoid arthritis. It is of note that these diseases share specific pathophysiological features with PSVD, including endothelial dysfunction, vascular inflammation, and molecular signatures. This narrative review aims to summarize the current knowledge on the association between PSVD and systemic autoimmune diseases, emphasizing the importance of promptly recognizing this condition in the rheumatological practice, and highlighting the key aspects where further research is necessary from both pathogenic and clinical perspectives.

The journey of STING: Guiding immune signaling through membrane trafficking

Stimulator of Interferon Genes (STING) serves as a pivotal mediator in the innate immune signaling pathway, transducing signals from various DNA receptors and playing a crucial role in natural immune processes. During cellular quiescence, STING protein resides in the endoplasmic reticulum (ER), and its activation typically occurs through the cGAS-STING signaling pathway. Upon activation, STING protein is transported to the Golgi apparatus, thereby initiating downstream signaling cascades. Vesicular transport serves as the primary mechanism for STING protein trafficking between the ER and Golgi apparatus, with COPII mediating anterograde transport from the ER to Golgi apparatus, while COPI is responsible for retrograde transport. Numerous factors influence these transport processes, thereby exerting either promoting or inhibitory effects on STING protein expression. Upon reaching the Golgi apparatus, to prevent over-activation, STING protein is transported to post-Golgi compartments for degradation. In addition to the conventional lysosomal degradation pathway, ESCRT has also been identified as one of the degradation pathways for STING protein. This review summarizes the recent findings on the membrane trafficking pathways of STING, highlighting their contributions to the regulation of cytokine production, the activation of immune cells, and the coordination of immune signaling pathways.

Successful Treatment of Stimulator of Interferon Genes-Associated Vasculopathy of Infantile Onset SAVI Syndrome With Anifrolumab

This case report describes a woman in her 30s who presented with cutaneous lesions since age of 2 to 3 years with erythema and pain on her nose, both cheeks, and ears when exposed to cold temperatures that progressed to nasal and auricular cartilage necrosis and was diagnosed with stimulator of interferon genes–associated vasculopathy with onset in infancy (SAVI syndrome).

Type I interferon pathway in pediatric systemic lupus erythematosus

BACKGROUND

The role of type I interferon (IFN-I) signaling in systemic lupus erythematosus (SLE) has been well established. However, unanswered questions remain regarding the applicability of these findings to pediatric-onset SLE. The aim of this review is to provide an overview of the novel discoveries on IFN-I signaling in pediatric-onset SLE.

DATA SOURCES

A literature search was conducted in the PubMed database using the following keywords: "pediatric systemic lupus erythematosus" and "type I interferon".

RESULTS

IFN-I signaling is increased in pediatric SLE, largely due to the presence of plasmacytoid dendritic cells and pathways such as cyclic GMP-AMP synthase-stimulator of interferon genes-TANK-binding kinase 1 and Toll-like receptor (TLR)4/TLR9. Neutrophil extracellular traps and oxidative DNA damage further stimulate IFN-I production. Genetic variants in IFN-I-related genes, such as IFN-regulatory factor 5 and tyrosine kinase 2, are linked to SLE susceptibility in pediatric patients. In addition, type I interferonopathies, characterized by sustained IFN-I activation, can mimic SLE symptoms and are thus important to distinguish. Studies on interferonopathies also contribute to exploring the pathogenesis of SLE. Measuring IFN-I activation is crucial for SLE diagnosis and stratification. Both IFN-stimulated gene expression and serum IFN-α2 levels are common indicators. Flow cytometry markers such as CD169 and galectin-9 are promising alternatives. Anti-IFN therapies, such as sifalimumab and anifrolumab, show promise in adult patients with SLE, but their efficacy in pediatric patients requires further investigation. Janus kinase inhibitors are another treatment option for severe pediatric SLE patients.

CONCLUSIONS

This review presents an overview of the IFN-I pathway in pediatric SLE. Understanding the intricate relationship between IFN-I and pediatric SLE may help to identify potential diagnostic markers and targeted therapies, paving the way for improved patient care and outcomes.

Ocular complications of SAVI: A unique case of bilateral uveitis and retinal vasculitis

Purpose

To describe a case of bilateral panuveitis in a patient with Stimulator of Interferon Genes (STING)-Associated Vasculitis with Onset in Infancy (SAVI).

Observations

A 45-year-old patient diagnosed with SAVI presented bilateral panuveitis and uncontrolled secondary intraocular hypertension due to structural complications from uveitis. Multimodal imaging revealed the presence of intraretinal fluid and bilateral vasculitis. The patient was started with systemic methotrexate.

Conclusions and importance

This case is essential to characterize ocular involvement in patients with SAVI. Awareness of these ocular manifestations is crucial for timely management and improvement of visual prognosis.

TREX-1 related Aicardi-Goutières syndrome improved by Janus kinase inhibitor

Aicardi-Goutières syndrome (AGS) is a genetic interferonopathy classically characterized by early onset of severe neurologic injury with basal ganglia calcifications, white matter abnormalities, and progressive cerebral atrophy, along with lymphocytosis and raised interferon alpha (INFα) in the cerebrospinal fluid (CSF). Here, we report a 31/2 year-old patient born with prenatal onset AGS, first manifesting as intra-uterine growth retardation. Cranial ultrasonography and cerebral MRI revealed ventriculomegaly and periventricular and basal ganglia calcifications, along with cerebral atrophy. Perinatal infections and known metabolic disorders were excluded. Both CSF lymphocytosis and raised INFα were present. Molecular analysis disclosed two already described compound heterozygous pathogenic variants in TREX1 (c. 309dup, p.(Thr104Hisfs*53) and c. 506G > A, p.(Arg169His)). The evolution was marked by severe global developmental delay with progressive microcephaly. Promptly, the patient developed irritability, quadri-paretic dyskinetic movements, and subsequently tonic seizures. Sensorineural hearing loss was detected as well as glaucoma. Initially, he was symptomatically treated with trihexyphenidyl followed by levetiracetam and topiramate. At age 22 months, baricitinib (0.4 mg/kg/day) was introduced, leading to normal serum INFα levels. Clinically, dyskinetic movements significantly decreased as well as irritability and sleep disturbance. We confirmed that baricitinib was a useful treatment with no major side effect.

STING-associated vasculopathy with onset in infancy (SAVI) presenting with skin lesions

STING-associated vasculopathy with onset in infancy (SAVI) is caused by pathogenic gain-of-function variants in the gene TMEM173 (also named stimulator of interferon genes, STING1). This report details the case of an 11-year-old girl with SAVI who presented with skin-limited symptoms and discusses the phenotype-genotype correlations of the TMEM173 variant present in our patient. Treatment of SAVI focuses on preventing the development or progression of organ damage by reducing systemic inflammation. We summarize the available treatments for this syndrome.

COVID-19 Vaccination in Patients with Inborn Errors of Immunity Reduces Hospitalization and Critical Care Needs Related to COVID-19: a USIDNET Report

BACKGROUND

The CDC and ACIP recommend COVID-19 vaccination for patients with inborn errors of immunity (IEI). Not much is known about vaccine safety in IEI, and whether vaccination attenuates infection severity in IEI.

OBJECTIVE

To estimate COVID-19 vaccination safety and examine effect on outcomes in patients with IEI.

METHODS

We built a secure registry database in conjunction with the US Immunodeficiency Network to examine vaccination frequency and indicators of safety and effectiveness in IEI patients. The registry opened on January 1, 2022, and closed on August 19, 2022.

RESULTS

Physicians entered data on 1245 patients from 24 countries. The most common diagnoses were antibody deficiencies (63.7%). At least one COVID-19 vaccine was administered to 806 patients (64.7%), and 216 patients received vaccination prior to the development of COVID-19. The most common vaccines administered were mRNA-based (84.0%). Seventeen patients were reported to seek outpatient clinic or emergency room care for a vaccine-related complication, and one patient was hospitalized for symptomatic anemia. Eight hundred twenty-three patients (66.1%) experienced COVID-19 infection. Of these, 156 patients required hospitalization (19.0%), 47 required ICU care (5.7%), and 28 died (3.4%). Rates of hospitalization (9.3% versus 24.4%, p < 0.001), ICU admission (2.8% versus 7.6%, p = 0.013), and death (2.3% versus 4.3%, p = 0.202) in patients who had COVID-19 were lower in patients who received vaccination prior to infection. In adjusted logistic regression analysis, not having at least one COVID-19 vaccine significantly increased the odds of hospitalization and ICU admission.

CONCLUSION

Vaccination for COVID-19 in the IEI population appears safe and attenuates COVID-19 severity.

Pediatric Neutrophilic Dermatoses

The term neutrophilic dermatosis encompasses a heterogeneous group of diseases, often associated with an underlying internal noninfectious disease, with an overlapping histopathologic background characterized by perivascular and diffuse neutrophilic infiltrates in one or more layers of the skin; extracutaneous neutrophilic infiltrates may be associated. Neutrophilic dermatoses are not frequent in children and, when they appear in this age group, represent a diagnostic and therapeutic challenge. Apart from the classic neutrophilic dermatoses such as pyoderma gangrenosum, Sweet syndrome, and Behçet disease, a neutrophilic dermatosis can be the presentation of rare genetic diseases of the innate immune system, such as autoinflammatory diseases.

Patient Experiences and Challenges in the Management of Autoinflammatory Diseases-Data from the International FMF & AID Global Association Survey

BACKGROUND

Autoinflammatory diseases (AIDs) are rare, mostly genetic diseases that affect the innate immune system and are associated with inflammatory symptoms. Both paediatric and adult patients face daily challenges related to their disease, diagnosis and subsequent treatment. For this reason, a survey was developed in collaboration between the FMF & AID Global Association and the Erlangen Center for Periodic Systemic Autoinflammatory Diseases.

METHODS

The aim of the survey was to collect the personal assessment of affected patients with regard to their current status in terms of diagnostic timeframes, the interpretation of genetic tests, the number of misdiagnoses, and pain and fatigue despite treatment.

RESULTS

In total, data from 1043 AID patients (829 adults and 214 children/adolescents) from 52 countries were collected and analyzed. Familial Mediterranean fever (FMF) (521/50%) and Behçet's disease (311/30%) were the most frequently reported diseases. The average time to diagnosis was 3 years for children/adolescents and 14 years for adults. Prior to the diagnosis of autoinflammatory disease, patients received several misdiagnoses, including psychosomatic disorders. The vast majority of patients reported that genetic testing was available (92%), but only 69% were tested. A total of 217 patients reported that no increase in acute-phase reactants was detected during their disease episodes. The intensity of pain and fatigue was measured in AID patients and found to be high. A total of 88% of respondents received treatment again, while 8% reported no treatment.

CONCLUSIONS

AID patients, particularly adults, suffer from significant delays in diagnosis, misdiagnosis, and a variety of symptoms, including pain and fatigue. Based on the results presented, raising awareness of these diseases in the wider medical community is crucial to improving patient care and quality of life.

A rare manifestation of STING-associated vasculopathy with onset in infancy: a case report

BACKGROUND

STING-associated vasculopathy with onset in infancy (SAVI) is a rare type I interferonopathy caused by heterozygous variants in the STING gene. In SAVI, STING variants confer a gain-of-function which causes overactivation of type I interferon (IFN) signaling leading to autoinflammation and various degrees of immunodeficiency and autoimmunity.

CASE PRESENTATION

We report the case of a 5 year old child and his mother, both of whom presented with systemic inflammatory symptoms yet widely varying organ involvement, disease course and therapeutic response. Genetic testing revealed a heterozygous STING variant, R281Q, in the child and his mother that had previously been associated with SAVI. However, in contrast to previously reported SAVI cases due to the R281Q variant, our patients showed an atypical course of disease with alopecia totalis in the child and a complete lack of lung involvement in the mother.

CONCLUSIONS

Our findings demonstrate the phenotypic breadth of clinical SAVI manifestations. Given the therapeutic benefit of treatment with JAK inhibitors, early genetic testing for SAVI should be considered in patients with unclear systemic inflammation involving cutaneous, pulmonary, or musculoskeletal symptoms, and signs of immunodeficiency and autoimmunity.

RelB-deficient autoinflammatory pathology presents as interferonopathy, but in mice is interferon-independent

BACKGROUND

Autoimmune diseases are leading causes of ill health and morbidity and have diverse etiology. Two signaling pathways are key drivers of autoimmune pathology, interferon and nuclear factor-κB (NF-κB)/RelA, defining the 2 broad labels of interferonopathies and relopathies. Prior work has established that genetic loss of function of the NF-κB subunit RelB leads to autoimmune and inflammatory pathology in mice and humans.

OBJECTIVE

We sought to characterize RelB-deficient autoimmunity by unbiased profiling of the responses of immune sentinel cells to stimulus and to determine the functional role of dysregulated gene programs in the RelB-deficient pathology.

METHODS

Transcriptomic profiling was performed on fibroblasts and dendritic cells derived from patients with RelB deficiency and knockout mice, and transcriptomic responses and pathology were assessed in mice deficient in both RelB and the type I interferon receptor.

RESULTS

We found that loss of RelB in patient-derived fibroblasts and mouse myeloid cells results in elevated induction of hundreds of interferon-stimulated genes. Removing hyperexpression of the interferon-stimulated gene program did not ameliorate the autoimmune pathology of RelB knockout mice. Instead, we found that RelB suppresses a different set of inflammatory response genes in a manner that is independent of interferon signaling but associated with NF-κB binding motifs.

CONCLUSION

Although transcriptomic profiling would describe RelB-deficient autoimmune disease as an interferonopathy, the genetic evidence indicates that the pathology in mice is interferon-independent.

Scope of JAK Inhibitors in Children: Recent Evidence and Way Forward

Over the last decade, there has been an increase in the use of targeted therapy using small molecules such as Janus kinase (JAK) inhibitors. Since the introduction of ruxolitinib, the first non-selective JAK inhibitor approved for use in myelofibrosis, many other JAK inhibitors have been tried in a wide spectrum of immune-mediated disorders. Although various trials have shown the promising efficacy of JAK inhibitors in immune-mediated inflammatory disorders (IMIDs), there is a growing concern over the major cardiovascular events and malignancies associated with the use of these molecules in older adults, particularly those over 65 years of age. In this review, we aim to discuss the immunology of the JAK-STAT pathway, the scope of use of JAK inhibitors, and their safety in paediatric practice. Here, we discuss high-quality evidence favouring the use of JAK inhibitors in children with juvenile idiopathic arthritis (JIA) who are refractory to one or more conventional/biological disease-modifying drugs, demonstrated in two randomised controlled trials (RCTs). In addition to JIA, there are reports favouring the role of JAK inhibitors in other IMIDs such as systemic-onset JIA and interferonopathies. Thus far, the existing literature suggests an acceptable safety profile for JAK inhibitors in children. With the expanding scope of JAK inhibitors in a wide range of IMIDs in children, there is a significant need for long-term close vigilance for any potential harm.

Targeted Treatment of Diseases of Immune Dysregulation

Increasing molecular knowledge of autoinflammatory and autoimmune disorders has enabled more targeted treatment of these conditions. Treatment of inflammasomopathies is often aimed at interleukin-1 (IL-1) blockade, with potential use of other inhibitors targeting cytokines such as IL-18 and IL-6. Interferonopathies and some disorders with overlap features of autoimmunity and autoinflammation may improve with Janus kinase inhibition. Autoimmune conditions may also respond to inhibition of different cytokines, as well as to inhibition of T and B lymphocytes. Effective treatment is increasingly possible through targeted/precision medicine approaches.

The 2022 EULAR/ACR Points to Consider at the Early Stages of Diagnosis and Management of Suspected Haemophagocytic Lymphohistiocytosis/Macrophage Activation Syndrome (HLH/MAS)

OBJECTIVE

Haemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) are life-threatening systemic hyperinflammatory syndromes that can develop in most inflammatory contexts. They can progress rapidly, and early identification and management are critical for preventing organ failure and mortality. This effort aimed to develop evidence-based and consensus-based points to consider to assist clinicians in optimising decision-making in the early stages of diagnosis, treatment and monitoring of HLH/MAS.

METHODS

A multinational, multidisciplinary task force of physician experts, including adult and paediatric rheumatologists, haematologist/oncologists, immunologists, infectious disease specialists, intensivists, allied healthcare professionals and patients/parents, formulated relevant research questions and conducted a systematic literature review (SLR). Delphi methodology, informed by SLR results and questionnaires of experts, was used to generate statements aimed at assisting early decision-making and optimising the initial care of patients with HLH/MAS.

RESULTS

The task force developed 6 overarching statements and 24 specific points to consider relevant to early recognition of HLH/MAS, diagnostic approaches, initial management and monitoring of HLH/MAS. Major themes included the simultaneous need for prompt syndrome recognition, systematic evaluation of underlying contributors, early intervention targeting both hyperinflammation and likely contributors, careful monitoring for progression/complications and expert multidisciplinary assistance.

CONCLUSION

These 2022 EULAR/American College of Rheumatology points to consider provide up-to-date guidance, based on the best available published data and expert opinion. They are meant to help guide the initial evaluation, management and monitoring of patients with HLH/MAS in order to halt disease progression and prevent life-threatening immunopathology.

The 2022 EULAR/ACR points to consider at the early stages of diagnosis and management of suspected haemophagocytic lymphohistiocytosis/macrophage activation syndrome (HLH/MAS)

OBJECTIVE

Haemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) are life-threatening systemic hyperinflammatory syndromes that can develop in most inflammatory contexts. They can progress rapidly, and early identification and management are critical for preventing organ failure and mortality. This effort aimed to develop evidence-based and consensus-based points to consider to assist clinicians in optimising decision-making in the early stages of diagnosis, treatment and monitoring of HLH/MAS.

METHODS

A multinational, multidisciplinary task force of physician experts, including adult and paediatric rheumatologists, haematologist/oncologists, immunologists, infectious disease specialists, intensivists, allied healthcare professionals and patients/parents, formulated relevant research questions and conducted a systematic literature review (SLR). Delphi methodology, informed by SLR results and questionnaires of experts, was used to generate statements aimed at assisting early decision-making and optimising the initial care of patients with HLH/MAS.

RESULTS

The task force developed 6 overarching statements and 24 specific points to consider relevant to early recognition of HLH/MAS, diagnostic approaches, initial management and monitoring of HLH/MAS. Major themes included the simultaneous need for prompt syndrome recognition, systematic evaluation of underlying contributors, early intervention targeting both hyperinflammation and likely contributors, careful monitoring for progression/complications and expert multidisciplinary assistance.

CONCLUSION

These 2022 EULAR/American College of Rheumatology points to consider provide up-to-date guidance, based on the best available published data and expert opinion. They are meant to help guide the initial evaluation, management and monitoring of patients with HLH/MAS in order to halt disease progression and prevent life-threatening immunopathology.

COVID-19 Vaccination In Patients with Inborn Errors of Immunity Reduces Hospitalization and Critical Care Needs Related to COVID-19: A USIDNET Report

Background

The CDC and ACIP recommend COVID-19 vaccination for patients with inborn errors of immunity (IEI). Not much is known about vaccine safety in IEI and whether vaccination attenuates infection severity in IEI.

Objective

To estimate COVID-19 vaccination safety and examine effect on outcomes in patients with IEI.

Methods

We built a secure registry database in conjunction with the United States Immunodeficiency Network to examine vaccination frequency and indicators of safety and effectiveness in IEI patients. The registry opened on January 1, 2022 and closed on August 19, 2022.

Results

Physicians entered data on 1,245 patients from 24 countries. The most common diagnoses were antibody deficiencies (63.7%). At least 1 COVID-19 vaccine was administered to 806 patients (64.7%), and 216 patients received vaccination prior to the development of COVID-19. The most common vaccines administered were mRNA-based (84.0%). Seventeen patients were reported to seek outpatient clinic or emergency room care for a vaccine-related complication and one patient was hospitalized for symptomatic anemia. Eight hundred twenty-three patients (66.1%) experienced COVID-19 infection. Of these, 156 patients required hospitalization (19.0%), 47 required ICU care (5.7%), and 28 died (3.4%). Rates of hospitalization (9.3% versus 24.4%, p<0.001), ICU admission (2.8% versus 7.6%, p=0.013), and death (2.3% versus 4.3%, p=0.202) in patients who had COVID-19 were lower in patients who received vaccination prior to infection. In adjusted logistic regression analysis, not having at least one COVID-19 vaccine significantly increased the odds of hospitalization and ICU admission.

Conclusion

Vaccination for COVID-19 in the IEI population appears safe and attenuates COVID-19 severity.

Treatment response to Janus kinase inhibitor in a child affected by Aicardi-Goutières syndrome

Key Clinical Message

Baricitinib, a Janus kinase inhibitor (JAK-inhibitor), seems to contribute to an improvement of a child affected by Aicardi-Goutières syndrome (AGS), reducing the interferon score and determining a recovery of cognitive, communicative, and relational dysfunctions, while the gross motor deficit persisted.

Abstract

We report the treatment response to baricitinib, a JAK-inhibitor, in a 4-year-old girl affected by Aicardi-Goutières syndrome (AGS2, RNASEH2B mutation). Using quantitative measures, we detected a significant amelioration characterized by a complete recovery of cognitive, communicative, and relational skills after 8 and 16 months from the beginning of therapy.

CSF neopterin and quinolinic acid are biomarkers of neuroinflammation and neurotoxicity in FIRES and other infection-triggered encephalopathy syndromes

OBJECTIVE

Infection-triggered encephalopathy syndromes (ITES) are potentially devastating neuroinflammatory conditions. Although some ITES syndromes have recognisable MRI neuroimaging phenotypes, there are otherwise few biomarkers of disease. Early detection to enable immune modulatory treatments could improve outcomes.

METHODS

We measured CSF neopterin, quinolinic acid, kynurenine and kynurenine/tryptophan ratio using a liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) system. The CSF of 18 children with ITES were compared with acute encephalitis (n = 20), and three control groups, namely epilepsy (n = 20), status epilepticus (n = 18) and neurogenetic controls (n = 20).

RESULTS

The main ITES phenotypes in 18 patients were acute encephalopathy with biphasic seizures and late restricted diffusion (AESD, n = 4), febrile infection-related epilepsy syndrome (FIRES n = 4) and other ITES phenotypes. Influenza A was the most common infectious trigger (n = 5), and 50% of patients had a preceding notable neurodevelopmental or family history. CSF neopterin, quinolinic acid and kynurenine were elevated in ITES group compared to the three control groups (all p < 0.0002). The ROC (area under curve) for CSF neopterin (99.3%, CI 98.1-100) was significantly better than CSF pleocytosis (87.3% CI 76.4-98.2) (p = 0.028). Elevated CSF neopterin could discriminate ITES from other causes of seizures, status epilepticus and febrile status epilepticus (all p < 0.0002). The elevated CSF metabolites normalised during longitudinal testing in two patients with FIRES.

INTERPRETATION

CSF neopterin and quinolinic acid are neuroinflammatory and excitotoxic metabolites. This CSF metabolomic inflammatory panel can discriminate ITES from other causes of new onset seizures or status epilepticus, and rapid results (4 h) may facilitate early immune modulatory therapy.

Update on autoinflammatory diseases

PURPOSE OF REVIEW

Although the concept of systemic autoinflammatory diseases (SAIDs) is still very young, our knowledge about them is exponentially growing. In the current review, we aim to discuss novel SAIDs and autoinflammatory pathways discovered in the last couple of years.

RECENT FINDINGS

Advances in immunology and genetics have led to the discovery of new pathways involved in autoinflammation, as well as several new SAIDs, including retinal dystrophy, optic nerve edema, splenomegaly, anhidrosis, and migraine headache (ROSAH syndrome), vacuoles, E1 enzyme, X-linked autoinflammatory somatic (VEXAS) syndrome, TBK1 deficiency, NEMO deleted exon 5 autoinflammatory syndrome (NDAS), and disabling pansclerotic morphea. Progress in immunobiology and genetics has also brought forth novel treatments for SAIDs. Personalized medicine has made significant progress in areas such as cytokine-targeted therapies and gene therapies. However, much work remains, especially in measuring and improving the quality of life in patients with SAIDs.

SUMMARY

In the current review, we discuss the novelties in the world of SAIDs, including mechanistic pathways of autoinflammation, pathogenesis, and treatment. We hope this review helps rheumatologists to gain an updated understanding of SAIDs.

Juvenile Dermatomyositis and Infantile Cerebral Palsy: Aicardi-Gouteres Syndrome, Type 5, with a Novel Mutation in SAMHD1-A Case Report

INTRODUCTION

Aicardi-Gouteres syndrome (AGS) is a monogenic interferonopathy characterized by early onset, dysregulation of skin (chilblain lesions), brain, and immune systems (fever, hepatomegaly, glaucoma, arthritis, myositis, and autoimmune activity). The disease looks like TORCH (Toxoplasmosis, Others, Rubella, Cytomegalovirus, Herpes) infection with early-onset encephalopathy resulting in severe neuropsychological disability.

CASE DESCRIPTION

A six-year-old girl has been suffering from generalized seizures, fever episodes, severe psychomotor development delay, and spastic tetraparesis since the first year of her life. Her two elder brothers died at a young age from suspected infantile cerebral palsy (ICP). Other siblings (younger brother and two elder sisters) are as healthy as their parents. The girl was diagnosed with juvenile dermatomyositis at 5.5 years. Basal ganglia, periventricular, and cerebellum calcifications; hypoplasia of the corpus callosum; and leukodystrophy were detected on CT. The IFN-I score was 12 times higher than normal. The previously not described nucleotide variant c.434G > C (chr 20:36935104C > G; NM_015474) was detected in exon 4 of the SAMHD1 gene in the homozygous state, leading to amino acid substitution p.R145P. Aicardi-Goutières syndrome 5 was diagnosed. Her treatment included corticosteroids, methotrexate, and tofacitinib 5 mg twice a day and it contributed to health improvements. The following brain CT depicted the previously discovered changes without the sign of calcification spreading.

CONCLUSIONS

Early diagnosis of AGS is highly important as it allows starting treatment in a timely manner. Timely treatment, in return, can help avoid the development/progression of end-organ damage, including severe neurological complications and early death. It is necessary to spread information about AGS among neurologists, neonatologists, infectious disease specialists, and pediatricians. A multidisciplinary team approach is required.

Dermatologic Manifestations of Noninflammasome-Mediated Autoinflammatory Diseases

Autoinflammatory diseases (AIDs) arise from disturbances that alter interactions of immune cells and tissues. They give rise to prominent (auto)inflammation in the absence of aberrant autoantibodies and/or autoreactive T cells. AIDs that are predominantly caused by changes in the inflammasome pathways, such as the NLRP3- or pyrin-associated inflammasome, have gained substantial attention over the last years. However, AIDs resulting primarily from other changes in the defense system of the innate immune system are less well-studied. These noninflammasome-mediated AIDs relate to, for example, disturbance in the TNF or IFN signaling pathways or aberrations in genes affecting the IL-1RA. The spectrum of clinical signs and symptoms of these conditions is vast. Thus, recognizing early cutaneous signs constitutes an important step in differential diagnoses for dermatologists and other physicians. This review provides an overview of the pathogenesis, clinical presentation, and available treatment options highlighting dermatologic aspects of noninflammasome-mediated AIDs.

The Genetic Landscape of Ischemic Stroke in Children - Current Knowledge and Future Perspectives

Stroke in childhood has multiple etiologies, which are mostly distinct from those in adults. Genetic discoveries over the last decade pointed to monogenic disorders as a rare but significant cause of ischemic stroke in children and young adults, including small vessel and arterial ischemic stroke. These discoveries contributed to the understanding that stroke in children may be a sign of an underlying genetic disease. The identification of these diseases requires a detailed medical and family history collection, a careful clinical evaluation for the detection of systemic symptoms and signs, and neuroimaging assessment. Establishing an accurate etiological diagnosis and understanding the genetic risk factors for stroke are essential steps to decipher the underlying mechanisms, optimize the design of tailored prevention strategies, and facilitate the identification of novel therapeutic targets in some cases. Despite the increasing recognition of monogenic causes of stroke, genetic disorders remain understudied and therefore under-recognized in children with stroke. Increased awareness among healthcare providers is essential to facilitate accurate diagnosis in a timely manner. In this review, we provide a summary of the main single-gene disorders which may present as ischemic stroke in childhood and describe their clinical manifestations. We provide a set of practical suggestions for the diagnostic work up of these uncommon causes of stroke, based upon the stroke subtype and imaging characteristics that may suggest a monogenic diagnosis of ischemic stroke in children. Current hurdles in the genetic analyses of children with ischemic stroke as well as future prospectives are discussed.

Intracellular Sensing of DNA in Autoinflammation and Autoimmunity

Evidence has shown that DNA is a pathogen-associated molecular pattern, posing a unique challenge in the discrimination between endogenous and foreign DNA. This challenge is highlighted by certain autoinflammatory diseases that arise from monogenic mutations and result in periodic flares of inflammation, typically in the absence of autoantibodies or antigen-specific T lymphocytes. Several autoinflammatory diseases arise due to mutations in genes that normally prevent the accrual of endogenous DNA or are due to mutations that cause activation of intracellular DNA-sensing pathway components. Evidence from genetically modified murine models further support an ability of endogenous DNA and DNA sensing to drive disease pathogenesis, prompting the question of whether endogenous DNA can also induce inflammation in human autoimmune diseases. In this review, we discuss the current understanding of intracellular DNA sensing and downstream signaling pathways as they pertain to autoinflammatory disease, including the development of monogenic disorders such as Stimulator of interferon genes-associated vasculopathy with onset in infancy and Aicardi-Goutières syndrome. In addition, we discuss systemic rheumatic diseases, including certain forms of systemic lupus erythematosus, familial chilblain lupus, and other diseases with established links to intracellular DNA-sensing pathways, and highlight the lessons learned from these examples as they apply to the development of therapies targeting these pathways.

The Autoinflammatory Diseases Alliance Registry of monogenic autoinflammatory diseases

Objective

The present manuscript aims to describe an international, electronic-based, user-friendly and interoperable patient registry for monogenic autoinflammatory diseases (mAIDs), developed in the contest of the Autoinflammatory Diseases Alliance (AIDA) Network.

Methods

This is an electronic platform, based on the Research Electronic Data Capture (REDCap) tool, used for real-world data collection of demographics, clinical, laboratory, instrumental and socioeconomic data of mAIDs patients. The instrument has flexibility, may change over time based on new scientific acquisitions, and communicate potentially with other similar registries; security, data quality and data governance are corner stones of the platform.

Results

AIDA project will share knowledge and expertise on mAIDs. Since its start, 118 centers from 24 countries and 4 continents have joined the AIDA project. Fifty-nine centers have already obtained the approval from their local Ethics Committees. Currently, the platform counts 337 users (122 Principal Investigators, 210 Site Investigators, 2 Lead Investigators, and 3 data managers). The Registry collects baseline and follow-up data using 3,748 fields organized into 21 instruments, which include demographics, patient history, symptoms, trigger/risk factors, therapies, and healthcare information for mAIDs patients.

Conclusions

The AIDA mAIDs Registry, acts both as a research tool for future collaborative real-life studies on mAIDs and as a service to connect all the figures called to participate. On this basis, the registry is expected to play a pivotal role in generating new scientific evidence on this group of rare diseases, substantially improving the management of patients, and optimizing the impact on the healthcare system. NCT 05200715 available at https://clinicaltrials.gov.

Developing guidelines for ultrarare rheumatic disorders: a bumpy ride

Clinical practice guidelines are useful tools for both patients and physicians. Several standardised operating procedures are in existence to describe tasks step by step to develop guidelines/recommendations. The end product consists of data synthesis from the systematic literature search and patient/physician's inputs. For the prevalent diseases, the process for developing guidelines is straightforward; it is based on physicians'/patients' experiences and abundance of the literature. When it comes to the realm of ultrarare diseases, there are few physicians who are familiar with a disease, and there is a scarcity of literature. In this viewpoint, we describe challenges from the methodological perspectives that occurred during the process of developing recommendations for autoinflammatory disorders with the goal of finding solutions that facilitate the development of guidelines for ultrarare diseases in the future.

Hematologic abnormalities in Aicardi Goutières Syndrome

BACKGROUND

Because of the broad clinical spectrum, heritable autoinflammatory diseases present a management and therapeutic challenge. The most common genetic interferonopathy, Aicardi Goutières Syndrome (AGS), is associated with early onset neurologic disability and systemic inflammation. The chronic inflammation of AGS is the result of dysregulation of interferon (IFN) expression by one of nine genes within converging pathways. While each AGS subtype shares common features, distinct patterns of severity and potential for systemic complications amongst the genotypes are emerging. Multilineage cytopenias are a potentially serious, but poorly understood, complication of AGS. As immunomodulatory treatment options are developed, it is important to characterize the role of the disease versus treatment in hematologic abnormalities. This will allow for better understanding and management of cytopenia.

METHODS

In total, 142 individuals with molecularly-confirmed AGS were included. Information on genotype, demographics, and all available hematologic laboratory values were collected from existing medical records. As part of a clinical trial, a subset of this cohort (n = 52) were treated with a janus kinase inhibitor (baricitinib), and both pre- and post-treatment values were included. Abnormal values were graded based on Common Terminology Criteria for Adverse Events (CTCAE v5.0), supplemented with grading definitions for thrombocytosis, and were compared across genotypes and baricitinib exposure.

RESULTS

In total, 11,184 laboratory values were collected over a median of 2.54 years per subject (range 0-22.68 years). To reduce bias from repeated sampling within a limited timeframe, laboratory results were restricted to the most abnormal value within a month (n = 8485). The most common abnormalities were anemia (noted in 24% of subjects prior to baricitinib exposure), thrombocytopenia (9%), and neutropenia (30%). Neutropenia was most common in the SAMHD1 cohort and increased with baricitinib exposure (38/69 measurements on baricitinib versus 14/121 while not on baricitinib). Having an abnormality prior to treatment was associated with having an abnormality on treatment for neutropenia and thrombocytopenia.

CONCLUSION

By collecting available laboratory data throughout the lifespan, we were able to identify novel patterns of hematologic abnormalities in AGS. We found that AGS results in multilineage cytopenias not limited to the neonatal period. Neutropenia, anemia, and thrombocytopenia were common. Moderate-severe graded events of neutropenia, anemia, and leukopenia were more common on baricitinib, but rarely of clinical consequence. Based on these results, we would recommend careful monitoring of hematologic parameters of children affected by AGS throughout the lifespan, especially while on therapy, and consideration of AGS as a potential differential diagnosis in children with neurologic impairment of unclear etiology with hematologic abnormalities. Trial registration ClinicalTrials.gov Identifier: NCT01724580 ClinicalTrials.gov Identifier: NCT03921554.

The Clinical Chameleon of Autoinflammatory Diseases in Children

The very first line of defense in humans is innate immunity, serving as a critical strongpoint in the regulation of inflammation. Abnormalities of the innate immunity machinery make up a motley group of rare diseases, named ‘autoinflammatory’, which are caused by mutations in genes involved in different immune pathways. Self-limited inflammatory bouts involving skin, serosal membranes, joints, gut and other districts of the human body burst and recur with variable periodicity in most autoinflammatory diseases (ADs), often leading to secondary amyloidosis as a long-term complication. Dysregulated inflammasome activity, overproduction of interleukin (IL)-1 or other IL-1-related cytokines and delayed shutdown of inflammation are pivotal keys in the majority of ADs. The recent progress of cellular biology has clarified many molecular mechanisms behind monogenic ADs, such as familial Mediterranean fever, tumor necrosis factor receptor-associated periodic syndrome (or ‘autosomal dominant familial periodic fever’), cryopyrin-associated periodic syndrome, mevalonate kinase deficiency, hereditary pyogenic diseases, idiopathic granulomatous diseases and defects of the ubiquitin-proteasome pathway. A long-lasting history of recurrent fevers should require the ruling out of chronic infections and malignancies before considering ADs in children. Little is known about the potential origin of polygenic ADs, in which sterile cytokine-mediated inflammation results from the activation of the innate immunity network, without familial recurrency, such as periodic fever/aphthous stomatitis/pharyngitis/cervical adenopathy (PFAPA) syndrome. The puzzle of febrile attacks recurring over time with chameleonic multi-inflammatory symptoms in children demands the inspection of the mixture of clinical data, inflammation parameters in the different disease phases, assessment of therapeutic efficacy of a handful of drugs such as corticosteroids, colchicine or IL-1 antagonists, and genotype analysis to exclude or confirm a monogenic origin.

Acrofacial necrotic ulcers in an infant: An undiagnosed presentation

Acral necrotic ulcers in infancy are rare but have been described in type I interferonopathies. Herein, we present a case of an 8-year-old child who presented at the age of one month with severe ulceronecrotic lesions on the face and limbs with exacerbations following exposure to cold weather. Despite extensive investigation the case remains undiagnosed to this day. We hypothesize that this case represents a novel and yet unknown autoinflammatory disease.