The Added Value of a Multidisciplinary Clinic for Systemic Autoinflammatory Diseases.

Background: Systemic autoinflammatory diseases (SAID) are characterized by inappropriate activation of the innate immune system and include not only monogenic periodic fever syndromes but also multifactorial conditions. As SAID are rare and represent a diagnostic challenge, a multidisciplinary approach is important to ensure successful diagnosis and adequate follow-up of these patients. Objective: To describe the organization of our multidisciplinary SAID clinic and to characterize our clinical experience, highlighting the benefits of multidisciplinary team management. Methods: Our SAID clinic takes place monthly and is managed by pediatric rheumatologists closely collaborating with pediatricians specialized in infectious diseases and immunodeficiencies and one medical geneticist. Patients' data are systematically incorporated in the Rheumatic Diseases Portuguese Register (Reuma.pt). Biological samples are stored in a biobank. We describe our clinical experience based on SAID patients registered into Reuma.pt/SAID between July 2011 and June 2020. Results: We have registered 176 patients, with a median age of disease onset of 3.1 ± 4.4 years and median age at disease diagnosis of 4.7 ± 4.0 years. Most patients were diagnosed with periodic fever, aphthous stomatitis, pharyngitis, adenitis syndrome (PFAPA) (n=133), 20 with undefined SAID (uSAID) and 13 with monogenic SAID, including familial Mediterranean fever (FMF) (n=5), tumor necrosis factor receptor-associated periodic syndrome (TRAPS) (n=1), cryopyrin-associated periodic disease (CAPS) (n=1), and hyperimmunoglobulin D syndrome/mevalonate kinase deficiency (HIDS/MKD) (n=2). A genetic test was performed in 31 patients (18%), and in 26% of these a mutation responsible for the phenotype was found. Thirty-four patients (19%) achieved remission. Conclusion: FMF was the most common monogenic SAID and the percentage of patients with an identified causal mutation was low. A structured electronic clinical record coupled with a biobank and a multidisciplinary approach are crucial to ensure successful diagnosis and adequate follow-up of these patients.