Juvenile neuropsychiatric systemic lupus erythematosus: A specific clinical phenotype and proposal of a probability score.

OBJECTIVE: Juvenile systemic lupus erythematosus (j-SLE) is a rare chronic auto-immune disease involving several organs. Neuropsychiatric (NP) SLE (NPSLE) is frequent in j-SLE and associated with increased morbidity/mortality. Although NPSLE classification criteria exist, attributing NP features to j-SLE remains a major challenge. The study objective is to thoroughly describe j-NPSLE patients and assist in their diagnosis. METHODS: This is a 4-year retrospective monocentric study of j-SLE patients. NP events were attributed to j-SLE using standardised diagnostic criteria and multidisciplinary paediatric clinical expertise. Clinical features, brain magnetic resonance imaging (MRI)s and samples analysis including cerebrospinal fluid were assessed. A risk of j-NPSLE score was developed based on multivariable logistic regression analysis. RESULTS: Of 39 patients included, 44% were identified as having j-NPSLE. J-NPSLE diagnosis was established at the onset of j-SLE in 59% of patients. In addition to frequent kidney involvement (76%) and chilblains (65%), all j-NPSLE patients displayed psychiatric features: cognitive symptoms (82%), hallucinations (76%), depressed mood (35%), acute confused state (18%) and catatonia (12%). Neurological involvement was often mild and nonspecific, with headache (53%) in about half of the patients. The main features reported on brain MRI were nonspecific T2/FLAIR white matter hyperintensities (65%), and cerebral atrophy (88%). Upon immunosuppressive treatment, clinical improvement of NP features was observed in all j-NPSLE patients. The score developed to attribute j-NPSLE probability, guide further investigations and appropriate treatments is based on hallucinations, memory, sleep and renal involvement (Sensitivity: 0.95 Specificity: 0.85). Cerebrospinal fluid (CSF) neopterin assessment increases the score sensitivity and specificity. CONCLUSION: Physicians should carefully and systematically assess the presence of NP features at diagnosis and early stages of j-SLE. For j-NPSLE patients with predominant psychiatric features, a multidisciplinary collaboration, including psychiatrists, is essential for the diagnosis, management and follow-up.

Physical fitness in adolescent patients with familial Mediterranean fever.

INTRODUCTION: Familial Mediterranean fever (FMF) is the most frequent monogenic auto-inflammatory disease worldwide responsible for episodes of fever, serositis and musculoskeletal symptoms. Inflammatory attacks are responsible for sedentary behavior and FMF patients may be at increased cardiovascular risk. Cardiorespiratory Fitness (CRF) and physical capacities during adolescence are associated with cardiovascular mortality in adulthood. In this study, we aimed to describe the physical fitness of FMF adolescents. METHODS: A monocentric retrospective study at the Versailles Hospital between January 2020 and June 2023. All FMF patients over 14-year-old who had completed a routine physical test were included. Clinical and physical data including results of the 6-minute walking test, timed unipedal stance test, Ruffier-Dickson index, 30-seconds chair-stand test and sit-and-reach test were extracted from medical records. Results were compared with previously published normative reference values and criterion-referenced standards for healthy subjects. RESULTS: Eighteen FMF patients (12 girls, 6 boys) were included. The median age was 16 years old [14-18]. Clinical history included joint symptoms (n = 11), chest pleuritis (n = 8), and leg pain (n = 11). Estimated VO2max was below the recommended thresholds in 13 patients, which predicts cardiovascular risk. Cardiovascular adaptation was poor in 11 patients. Low VO2max was associated with CRP > 5 mg/l on test day and history of joint symptoms. CONCLUSION: FMF patients displayed altered physical capacities compared to normative values of healthy subjects. History of musculoskeletal pain, systemic inflammation and sedentary behavior may participate in impaired physical abilities and promote cardiovascular diseases in adulthood. Specific exercise programs could benefit patients for disease control and cardiovascular risk reduction.

Successful treatment of JAK1-associated inflammatory disease.

BACKGROUND: Gain-of-function variants of JAK1 drive a rare immune dysregulation syndrome associated with atopic dermatitis, allergy, and eosinophilia. OBJECTIVES: This study sought to describe the clinical and immunological characteristics associated with a new gain-of-function variant of JAK1 and report the therapeutic efficacy of Janus kinase (JAK) inhibition. METHODS: The investigators identified a family affected by JAK1-associated autoinflammatory disease and performed clinical assessment and immunological monitoring on 9 patients. JAK1 signaling was studied by flow and mass cytometry in patients' cells at basal state or after immune stimulation. A molecular disease signature in the blood was studied at the transcriptomic level. Patients were treated with 1 of 2 JAK inhibitors: either baricitinib or upadacitinib. Clinical, cellular, and molecular response were evaluated over a 2-year period. RESULTS: Affected individuals displayed a syndromic disease with prominent allergy including atopic dermatitis, ichthyosis, arthralgia, chronic diarrhea, disseminated calcifying fibrous tumors, and elevated whole blood histamine levels. A variant of JAK1 localized in the pseudokinase domain was identified in all 9 affected, tested patients. Hyper-phosphorylation of STAT3 was found in 5 of 6 patients tested. Treatment of patients' cells with baricitinib controlled most of the atypical hyper-phosphorylation of STAT3. Administration of baricitinib to patients led to rapid improvement of the disease in all adults and was associated with reduction of systemic inflammation. CONCLUSIONS: Patients with this new JAK1 gain-of-function pathogenic variant displayed very high levels of blood histamine and showed a variable combination of atopy with articular and gastrointestinal manifestations as well as calcifying fibrous tumors. The disease, which appears to be linked to STAT3 hyperactivation, was well controlled under treatment by JAK inhibitors in adult patients.

Juvenile Neuropsychiatric Systemic Lupus Erythematosus: Identification of Novel Central Neuroinflammation Biomarkers.

INTRODUCTION: Juvenile systemic lupus erythematosus (j-SLE) is a rare chronic autoimmune disease affecting multiple organs. Ranging from minor features, such as headache or mild cognitive impairment, to serious and life-threatening presentations, j-neuropsychiatric SLE (j-NPSLE) is a therapeutic challenge. Thus, the diagnosis of NPSLE remains difficult, especially in pediatrics, with no specific biomarker of the disease yet validated. OBJECTIVES: To identify central nervous system (CNS) disease biomarkers of j-NPSLE. METHODS: A 5-year retrospective tertiary reference monocentric j-SLE study. A combination of standardized diagnostic criteria and multidisciplinary pediatric clinical expertise was combined to attribute NP involvement in the context of j-SLE. Neopterin and interferon-alpha (IFN-α) protein levels in cerebrospinal fluid (CSF) were assessed, together with routine biological and radiological investigations. RESULTS: Among 51 patients with j-SLE included, 39% presented with j-NPSLE. J-NPSLE was diagnosed at onset of j-SLE in 65% of patients. No specific routine biological or radiological marker of j-NPSLE was identified. However, CSF neopterin levels were significantly higher in active j-NPSLE with CNS involvement than in j-SLE alone (p = 0.0008). Neopterin and IFN-α protein levels in CSF were significantly higher at diagnosis of j-NPSLE with CNS involvement than after resolution of NP features (respectively p = 0.0015 and p = 0.0010) upon immunosuppressive treatment in all patients tested (n = 10). Both biomarkers correlated strongly with each other (Rs = 0.832, p < 0.0001, n = 23 paired samples). CONCLUSION: CSF IFN-α and neopterin constitute promising biomarkers useful in the diagnosis and monitoring of activity in j-NPSLE.

Neurological manifestations in mevalonate kinase deficiency: A systematic review.

INTRODUCTION: Mevalonate kinase deficiency (MKD) is a monogenic auto-inflammatory disease. Its manifestations range from partial MKD to mevalonic aciduria (MVA). All patients display a periodic fever, and MVA patients additionally exhibit severe neurological involvement. The objective of this work was to describe neurological manifestations of MKD. METHODS: A systematic literature review was performed from January 1990 to January 2022. Forty-five patients from 18 case reports and five cohort studies were included in the analysis. RESULTS: In cohort studies, the most-reported manifestations were headaches (41%) and fatigue (31%). Serious involvements including ataxia and developmental delay were described less than 1% of patients but 22-31% of case reports. They consistently appeared in the first years of life. Retinal dystrophy was frequently reported (31%) in case reports. Other manifestations, including uveitis, aseptic meningitis, and stroke remained rare. DISCUSSION: Severe neurological manifestations are rare in MKD but are responsible for major functional disabilities. They are present at onset and never appear at follow-up of patients with mild MKD. Conversely, headaches and fatigue are frequent symptoms that should be investigated. Visual examinations should be performed on the appearance of visual symptoms. The efficacy of anti-IL-1ß therapy on neurological manifestations should be further investigated.

Differential Expression of Interferon-Alpha Protein Provides Clues to Tissue Specificity Across Type I Interferonopathies.

Whilst upregulation of type I interferon (IFN) signaling is common across the type I interferonopathies (T1Is), central nervous system (CNS) involvement varies between these disorders, the basis of which remains unclear. We collected cerebrospinal fluid (CSF) and serum from patients with Aicardi-Goutières syndrome (AGS), STING-associated vasculopathy with onset in infancy (SAVI), presumed monogenic T1Is (pT1I), childhood systemic lupus erythematosus with neuropsychiatric features (nSLE), non-IFN-related autoinflammation (AI) and non-inflammatory hydrocephalus (as controls). We measured IFN-alpha protein using digital ELISA. Eighty-two and 63 measurements were recorded respectively in CSF and serum of 42 patients and 6 controls. In an intergroup comparison (taking one sample per individual), median CSF IFN-alpha levels were elevated in AGS, SAVI, pT1I, and nSLE compared to AI and controls, with levels highest in AGS compared to all other groups. In AGS, CSF IFN-alpha concentrations were higher than in paired serum samples. In contrast, serum IFN was consistently higher compared to CSF levels in SAVI, pT1I, and nSLE. Whilst IFN-alpha is present in the CSF and serum of all IFN-related diseases studied here, our data suggest the primary sites of IFN production in the monogenic T1I AGS and SAVI are, respectively, the CNS and the periphery. These results inform the diagnosis of, and future therapeutic approaches to, monogenic and multifactorial T1Is.

Rapid screening of COVID-19 patients using white blood cell scattergrams, a study on 381 patients.

Complementary tools are warranted to increase the sensitivity of the initial testing for COVID-19. We identified a specific 'sandglass' aspect on the white blood cell scattergram of COVID-19 patients reflecting the presence of circulating plasmacytoid lymphocytes. Patients were dichotomized as COVID-19-positive or -negative based on reverse transcriptase polymerase chain reaction (RT-PCR) and chest computed tomography (CT) scan results. Sensitivity and specificity of the 'sandglass' aspect were 85·9% and 83·5% respectively. The positive predictive value was 94·3%. Our findings provide a non-invasive and simple tool to quickly categorize symptomatic patients as either COVID-19-probable or -improbable especially when RT-PCR and/or chest CT are not rapidly available.

Validation of the new classification criteria for hereditary recurrent fever in an independent cohort: experience from the JIR Cohort Database.

OBJECTIVE: The new classification criteria for the hereditary recurrent fever (HRF) syndrome [cryopyrin-associated periodic syndrome (CAPS), TNF-α receptor-associated periodic syndrome (TRAPS), FMF and mevalonate kinase deficiency] have been published recently. These criteria define two core sets of criteria for each HRF: mixed criteria, including genetic and clinical variables, and clinical criteria, relying on clinical variables only. Our aim was to validate the criteria for HRF in an independent cohort, the JIR Cohort database, an international repository of systemic inflammatory diseases. METHODS: We enrolled patients with HRF, periodic fever, adenitis, pharyngitis and aphthous stomatitis syndrome (PFAPA) and syndrome of undefined recurrent fever (SURF). A score ranging from zero to two was attributed to their respective genotypes: zero (no mutation), one (non-confirmatory genotype) or two (confirmatory genotype). The criteria were applied to all patients based on genotype scoring. The treating physician's diagnosis served as the gold standard for the determination of specificity. RESULTS: We included 455 patients. The classification criteria showed excellent specificity for CAPS and TRAPS (98% specificity each), fair specificity for FMF (88%), but poor specificity for mevalonate kinase deficiency (58%). Sub-analysis showed excellent accuracy of the mixed criteria for all four HRFs. Misclassification was mainly attributable to clinical criteria sets, with false-positive patients in all four HRF clinical criteria sets. CONCLUSION: This study represents the final validation step of the HRF classification criteria as recommended by the ACR. Genetic data appear to be necessary to classify patients with HRF correctly.

Non-amyloid liver involvement in familial Mediterranean fever: A systematic literature review.

INTRODUCTION: Familial Mediterranean fever (FMF), the most frequent autoinflammatory disease, is caused by mutations in the MEFV gene. It is characterized by recurrent febrile attacks of polyserositis. Liver abnormalities may develop during its course, but they remain poorly defined. OBJECTIVE: To describe liver involvement in FMF patients. METHODS: A systematic search was conducted through PubMed/Medline and Embase from 1946 to January 2020. All articles describing children and adults with FMF and liver involvement were included. Patients with amyloidosis were excluded. The selected full-text articles were independently reviewed by three investigators. RESULTS: Forty-three articles were identified, of which 20 articles with a total of 99 patients were included: 74 adults, 23 children and two patients of unknown age. Ten patients had cryptogenic cirrhosis, 48 had nonalcoholic fatty liver disease (NAFLD), four had Budd-Chiari syndrome (BCS), 12 had isolated hyperbilirubinaemia and 25 had elevated liver enzymes. CONCLUSION: Despite a low prevalence of metabolic risk factors, FMF may be associated with NAFLD and cryptogenic cirrhosis as a consequence of chronic or recurrent inflammation. FMF patients should be regularly screened for liver injury. The latter may be prevented and treated by daily colchicine intake. The evidence was insufficient to establish an association with BCS, hyperbilirubinaemia or autoimmune hepatitis.

Burden of illness in hereditary periodic fevers: a multinational observational patient diary study.

OBJECTIVES: This study aimed to characterise the burden of illness of patients with inadequately controlled hereditary periodic fevers (HPFs), during and outside of flares. It was focused on the burden to the patients and also considered the wider impact on their caregivers and families. METHODS: The target population was patients or caregivers of patients with clinically/genetically confirmed colchicine resistant FMF (crFMF), mevalonate kinase deficiency/hyperimmunoglobinaemia D with periodic fever syndrome (MKD/HIDS) or TRAPS, who were expected to flare at least once in a 6-month period based on patient history. Disease burden was captured during and between flares using an electronic diary (e-diary) with questions on patient functioning, emotional/social well-being and pain, using validated instruments. RESULTS: HPF-related symptoms such as fever, joint, muscle or bone pain and tiredness and fatigue were reported by patients both during and outside of a flare. The SF-10 Health Survey (SF-10v2) (paediatric patients) and SF-12 Health Survey (SF-12v2) (adult patients) showed that flares negatively impacted patients' psychosocial and physical health. Negative effect of on-flare status on health utility index score assessed by the Short-Form Six-Dimension (SF-6D) was significant only for crFMF patients. Furthermore, the Sheehan Disability Score (SDSv3) showing the on-flare status resulted in significant functional impairment in all 3 disease cohorts through assessment of impact on work/school, social and family life. CONCLUSIONS: crFMF, MKD/HIDS and TRAPS negatively affected the quality of life (QoL) of adult and paediatric patients, including their physical, mental, psychosocial health, and social functioning. There remains, however, a high number of unmet needs for these patients to reduce their disease burden.

SARS-CoV-2-related paediatric inflammatory multisystem syndrome, an epidemiological study, France, 1 March to 17 May 2020.

End of April 2020, French clinicians observed an increase in cases presenting with paediatric inflammatory multisystem syndrome (PIMS). Nationwide surveillance was set up and demonstrated temporospatial association with the coronavirus disease (COVID-19) epidemic for 156 reported cases as at 17 May: 108 were classified as confirmed (n = 79), probable (n = 16) or possible (n = 13) post-COVID-19 PIMS cases. A continuum of clinical features from Kawasaki-like disease to myocarditis was observed, requiring intensive care in 67% of cases.

Classification criteria for autoinflammatory recurrent fevers.

BACKGROUND: Different diagnostic and classification criteria are available for hereditary recurrent fevers (HRF)-familial Mediterranean fever (FMF), tumour necrosis factor receptor-associated periodic fever syndrome (TRAPS), mevalonate kinase deficiency (MKD) and cryopyrin-associated periodic syndromes (CAPS)-and for the non-hereditary, periodic fever, aphthosis, pharyngitis and adenitis (PFAPA). We aimed to develop and validate new evidence-based classification criteria for HRF/PFAPA. METHODS: Step 1: selection of clinical, laboratory and genetic candidate variables; step 2: classification of 360 random patients from the Eurofever Registry by a panel of 25 clinicians and 8 geneticists blinded to patients' diagnosis (consensus ≥80%); step 3: statistical analysis for the selection of the best candidate classification criteria; step 4: nominal group technique consensus conference with 33 panellists for the discussion and selection of the final classification criteria; step 5: cross-sectional validation of the novel criteria. RESULTS: The panellists achieved consensus to classify 281 of 360 (78%) patients (32 CAPS, 36 FMF, 56 MKD, 37 PFAPA, 39 TRAPS, 81 undefined recurrent fever). Consensus was reached for two sets of criteria for each HRF, one including genetic and clinical variables, the other with clinical variables only, plus new criteria for PFAPA. The four HRF criteria demonstrated sensitivity of 0.94-1 and specificity of 0.95-1; for PFAPA, criteria sensitivity and specificity were 0.97 and 0.93, respectively. Validation of these criteria in an independent data set of 1018 patients shows a high accuracy (from 0.81 to 0.98). CONCLUSION: Eurofever proposes a novel set of validated classification criteria for HRF and PFAPA with high sensitivity and specificity.

The European network for care of children with paediatric rheumatic diseases: care across borders.

OBJECTIVES: To provide an overview of the paediatric rheumatology (PR) services in Europe, describe current delivery of care and training, set standards for care, identify unmet needs and inform future specialist service provision. METHODS: An online survey was developed and presented to national coordinating centres of the Paediatric Rheumatology International Trials Organisation (PRINTO) (country survey) and to individual PR centres (centre and disease surveys) as a part of the European Union (EU) Single Hub and Access point for paediatric Rheumatology in Europe project. The survey contained components covering the organization of PR care, composition of teams, education, health care and research facilities and assessment of needs. RESULTS: Response rates were 29/35 (83%) for country surveys and 164/288 (57%) for centre surveys. Across the EU, approximately one paediatric rheumatologist is available per million population. In all EU member states there is good access to specialist care and medications, although biologic drug availability is worse in Eastern European countries. PR education is widely available for physicians but is insufficient for allied health professionals. The ability to participate in clinical trials is generally high. Important gaps were identified, including lack of standardized clinical guidelines/recommendations and insufficient adolescent transition management planning. CONCLUSION: This study provides a comprehensive description of current specialist PR service provision across Europe and did not reveal any major differences between EU member states. Rarity, chronicity and complexity of diseases are major challenges to PR care. Future work should facilitate the development, dissemination and implementation of standards of care, treatment and service recommendations to further improve patient-centred health care across Europe.

In silico validation of the Autoinflammatory Disease Damage Index.

INTRODUCTION: Autoinflammatory diseases can cause irreversible tissue damage due to systemic inflammation. Recently, the Autoinflammatory Disease Damage Index (ADDI) was developed. The ADDI is the first instrument to quantify damage in familial Mediterranean fever, cryopyrin-associated periodic syndromes, mevalonate kinase deficiency and tumour necrosis factor receptor-associated periodic syndrome. The aim of this study was to validate this tool for its intended use in a clinical/research setting. METHODS: The ADDI was scored on paper clinical cases by at least three physicians per case, independently of each other. Face and content validity were assessed by requesting comments on the ADDI. Reliability was tested by calculating the intraclass correlation coefficient (ICC) using an 'observer-nested-within-subject' design. Construct validity was determined by correlating the ADDI score to the Physician Global Assessment (PGA) of damage and disease activity. Redundancy of individual items was determined with Cronbach's alpha. RESULTS: The ADDI was validated on a total of 110 paper clinical cases by 37 experts in autoinflammatory diseases. This yielded an ICC of 0.84 (95% CI 0.78 to 0.89). The ADDI score correlated strongly with PGA-damage (r=0.92, 95% CI 0.88 to 0.95) and was not strongly influenced by disease activity (r=0.395, 95% CI 0.21 to 0.55). After comments from disease experts, some item definitions were refined. The interitem correlation in all different categories was lower than 0.7, indicating that there was no redundancy between individual damage items. CONCLUSION: The ADDI is a reliable and valid instrument to quantify damage in individual patients and can be used to compare disease outcomes in clinical studies.

Familial Mediterranean fever mutations are hypermorphic mutations that specifically decrease the activation threshold of the Pyrin inflammasome.

Objectives: FMF is the most frequent autoinflammatory disease and is associated in most patients with bi-allelic MEFV mutations. MEFV encodes Pyrin, an inflammasome sensor activated following RhoGTPase inhibition. The functional consequences of MEFV mutations on the ability of Pyrin variants to act as inflammasome sensors are largely unknown. The aim of this study was to assess whether MEFV mutations affect the ability of Pyrin to detect RhoGTPase inhibition and other inflammasome stimuli. Methods: IL-1ß and IL-18 released by monocytes from healthy donors (HDs) and FMF patients were measured upon specific engagement of the Pyrin, NLRP3 and NLRC4 inflammasomes. Cell death kinetics following Pyrin activation was monitored in real time. Results: Monocytes from FMF patients secreted significantly more IL-1ß and IL-18 and died significantly faster than HD monocytes in response to low concentrations of Clostridium difficile toxin B (TcdB), a Pyrin-activating stimulus. Monocytes from patients bearing two MEFV exon 10 pathogenic variants displayed an increased Pyrin inflammasome response compared with monocytes from patients with a single exon 10 pathogenic variant indicating a gene-dosage effect. Using a short priming step, the response of monocytes from FMF patients to NLRP3- and NLRC4-activating stimuli was normal indicating that MEFV mutations trigger a specific hypersensitivity of monocytes to low doses of a Pyrin-engaging stimulus. Conclusion: Contrary to the NLRP3 mutations described in cryopyrin-associated periodic syndrome, FMF-associated MEFV mutations do not lead to a constitutive activation of Pyrin. Rather, FMF-associated mutations are hypermorphic mutations that specifically decrease the activation threshold of the Pyrin inflammasome without affecting other canonical inflammasomes.

[Recurrent auto-inflammatory fevers : a practical diagnostic flow chart]. / Fièvres récurrentes auto-inflammatoires : la bonne démarche diagnostique.

Recurrent autoinflammatory fever syndromes are characterized by an abnormal activation of the innate immune system pathways, leading to inappropriate systemic inflammation responsible for clinical symptoms. The diagnosis of these conditions is difficult because of their low prevalence, but also because of their nonspecific clinical signs. The presence of clinical inflammatory signs such as fever associated to serositis (arthritis, peritonitis …) or recurrent cutaneous manifestations and elevated acute phase reactants should help the clinician to make the correct diagnosis. The purpose of this article is to provide a practical management flow chart for children with a suspected autoinflammatory recurrent fever syndrome.

Les fièvres récurrentes auto-inflammatoires sont un groupe de pathologies qui ont comme point commun une activation anormale du système immunitaire inné, en bonne partie liées à des mutations dans les gènes régulateurs des cascades inflammatoires. Le diagnostic de ces pathologies est difficile en raison de leur faible prévalence, mais aussi de leurs signes cliniques peu spécifiques. La présence de signes cliniques et biologiques inflammatoires tels que de la fièvre associée à une inflammation des séreuses (arthrite, péritonite…) et de signes cliniques cutanés récurrents doit faire évoquer le diagnostic et conduire à une analyse sémiologique fine afin de pouvoir poser un diagnostic précis. Cet article propose une conduite à tenir de pratique clinique courante devant un enfant atteint d'une fièvre à répétition.

Development of the autoinflammatory disease damage index (ADDI).

OBJECTIVES: Autoinflammatory diseases cause systemic inflammation that can result in damage to multiple organs. A validated instrument is essential to quantify damage in individual patients and to compare disease outcomes in clinical studies. Currently, there is no such tool. Our objective was to develop a common autoinflammatory disease damage index (ADDI) for familial Mediterranean fever, cryopyrin-associated periodic syndromes, tumour necrosis factor receptor-associated periodic fever syndrome and mevalonate kinase deficiency. METHODS: We developed the ADDI by consensus building. The top 40 enrollers of patients in the Eurofever Registry and 9 experts from the Americas participated in multiple rounds of online surveys to select items and definitions. Further, 22 (parents of) patients rated damage items and suggested new items. A consensus meeting was held to refine the items and definitions, which were then formally weighted in a scoring system derived using decision-making software, known as 1000minds. RESULTS: More than 80% of the experts and patients completed the online surveys. The preliminary ADDI contains 18 items, categorised in the following eight organ systems: reproductive, renal/amyloidosis, developmental, serosal, neurological, ears, ocular and musculoskeletal damage. The categories renal/amyloidosis and neurological damage were assigned the highest number of points, serosal damage the lowest number of points. The involvement of (parents of) patients resulted in the inclusion of, for example, chronic musculoskeletal pain. CONCLUSIONS: An instrument to measure damage caused by autoinflammatory diseases is developed based on consensus building. Patients fulfilled a significant role in this process.