P14 | A rare case of VEXAS syndrome

Premises: VEXAS syndrome (Vacuoles, E1 enzyme, X-linked, Autoinflammatory, Somatic) is a rare late-onset autoinflammatory syndrome caused by a mutation in the UBA1 gene. It primarily affects men over 50 with a presentation that mimics autoimmune disorders (Sweet's syndrome, polychondritis, vasculitis) associated with hematological disorders (cytopenias, MDS, thromboembolic events).Clinical Case Description: Male, 55 years old. May 2022: diagnosis of macrocytic anemia and thrombocytopenia. BOM performed with a diagnosis of low-risk multilineage MDS, normal karyotype, EPN clone absent, indication for follow-up. October 2022: onset of fever, skin rash, widespread arthralgia, and autoimmune hemolytic anemia. They ruled out infectious causes, autoimmune serology, total-body CT scans, and PET scans. Started steroid 1 mg/kg with benefit. February 2023: reappearance of fever, anemia, thrombocytopenia, extreme reticulocytosis, but a negative Coombs test. It was associated with the appearance of Libman-Sacks endocarditis. A new cycle of cortisone has been administered. April 2023 repeated bone marrow aspiration with confirmation of MDS diagnosis. Cyclosporine therapy was initiated, followed by rituximab, with benefit on symptoms and improvement in blood count. In the presence of a picture of dysimmunity and MDS, a genetic test for the UBA1 mutation was performed, which was found to be present. The patient has been started on an allogeneic bone marrow transplant pathway.Conclusions: VEXAS syndrome is a rare autoinflammatory syndrome that should be considered in cases of hematological damage and symptoms of systemic inflammation in the absence of active rheumatological disease.