AB0016 CASE SERIES OF AUTOINFLAMMATORY SYNDROMES IN ADULTHOOD
Authors: N. Garvin Grande, P. Turiel, M. Beladiez Giner, C. Zamora Ramos, M. Alcalde Villar, P. Collado
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Autoinflammatory syndromes (AIS) are a group of inherited diseases characterized by increased systemic inflammation caused by disorders in the innate immune system. They include both monogenic Mendelian diseases and more complex polygenic entities, which have mutations in genes involved in the control of various inflammatory pathways and present with periodic or persistent clinical pictures. They are characterized by a pediatric onset and diagnosis, although there is an increasing number of reported cases of late onset in adulthood. The heterogeneous nature of these diseases, which in many cases present with mild symptoms, often leads to diagnostic delays. Therefore, it is important to be aware of the peculiarities of these syndromes and to maintain a high clinical suspicion to reach a final diagnosis. <h3>Objectives:</h3> To describe the clinical and therapeutic characteristics of adult patients with AIS. <h3>Methods:</h3> Descriptive, observational, and retrospective study. Patients over 16 years of age with a high clinical suspicion of AIS were included from a database of a rheumatology department of a non-reference center (hospital, level 2) from 2005 to 2023. Variables collected: sex, age and symptoms at debut, age at diagnosis, delay time to diagnosis, genetic mutation, clinical characteristics, treatments, and laboratory parameters such as erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and ferritin. Descriptive statistics were expressed as mean (standard deviation, SD) or median (interquartile range, IQR) to describe continuous variables, and percentages for categorical variables. The diagnosis was made by diagnostic classification criteria (Yamaguchi 1992 for adult Still's disease and Eurofever 2015 for tumor necrosis factor receptor-associated periodic syndrome (TRAPS) mutations), or by genetic study. Patients with a positive genetic study and those with an inconclusive study having ruled out infectious, autoimmune, or neoplastic causes were included. <h3>Results:</h3> Eight patients with a diagnosis of suspected AIS were analyzed. The mean age was 55.5 ±20.3 years, with no gender predominance (50% male), and the majority were Caucasian. Adult Still's disease was the most frequent AIS, 3 patients (37.5%). The mean age at symptom onset was 40 ±23 years, with a mean age at disease diagnosis of 45.6 ±20.7. The onset of symptoms or characteristic signs of the disease occurred in adulthood in 7 (87.5%) of the cases. Only one patient had clinical onset in the pediatric age group. Overall, a mean delay in final diagnosis of 5.7± 5 years was observed. The main characteristics of the included AIS are listed in Table 1. Elevation of acute phase reactants was collected in 7 (87.5%) of the cases. The mean value was 187 ±110 mg/L for CRP and 95.2 ±38 mm/h for ESR. Median ferritin was 923.5 ng/mL (329-15410). All patients, but one, were taking corticosteroids. Interleukin-1 inhibitor (IL-1-i) therapy was reported in half of the study population (4 patients). Three of these four patients underwent an IL-1-i switched from Anakinra to Canakinumab due to intolerance to daily injection in the patient with pediatric debut and secondary therapy failure in the other two cases. To date, all patients included in the study have had adequate control of disease activity. <h3>Conclusion:</h3> We describe a representative sample of AIS that showed up in daily clinical practice from a non-expertise centre. It is important to maintain a high suspicion for early identification of AIS, as usual antirheumatic therapy is not effective and almost al need systemic steroids. Prescription of IL-1-I usually achieves adequate disease control. The increasing identification of AIS in adulthood forces the adult rheumatologist to open mind regardless of where he or she works. Further studies are needed to improve the understanding of adult AIS. <h3>REFERENCES:</h3> <b>NIL.</b> <b>Table 1.</b> Main characteristics of autoinflammatory syndromes (AIS). <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> <b>None declared.</b>