DECIPHERING AND TARGETING VEXAS

VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome (1/4,000 males aged \>50) is a paradigmatic age-onset acquired, severe, autoinflammatory hematological disease due to clonal dominance of hematopoietic cells bearing a somatic mutation in the UBA1 (ubiquitin-activating enzyme 1) gene. VEXAS presents with treatment-refractory systemic myeloid-driven inflammatory manifestations and hematologic abnormalities, hence the poor prognosis. Current available therapies are poorly effective and burdened by debilitating side effects. VEXAS mutations inactivate cytoplasmic UBA1-driven ubiquitination, impairing protein clearance and triggering stress responses. By innovative base-editing (patent PCTIB2024060412), the investigators generated new in vitro and in vivo models that, along with comprehensive phenotyping of VEXAS patients, disclosed progressive inflammatory poisoning of healthy hematopoiesis and resilience to inflammation of UBA1-mutant hematopoietic stem/progenitor cells (HSPC) as key mechanisms of inflammation and clonal dominance. Deciphering these mechanisms might reveal predictive markers, actionable targets, and inform drug repurposing or novel therapies. The investigators hypothesize that cell-intrinsic and -extrinsic mechanisms triggered by altered UBA1 function are targetable drivers linking inflammation and clonal dominance. The research plan is designed to investigate, both in vitro and in BM and peripheral hematopoietic cells from VEXAS patients, the key pathogenic mechanisms sustaining inflammation and clonal dominance in VEXAS syndrome. Patients with VEXAS syndrome, defined by the presence of pathogenic mutations in the UBA1 gene identified in hematopoietic cells isolated from the peripheral blood of individuals with systemic autoinflammatory disease, will be included in the study population. The study will also enroll healthy control subjects, matched as closely as possible for age and sex, with no history of inflammatory or hematologic disorders. The dissection of mechanisms underlying the interplay between inflammation and clonal dominance will be fundamental to identify novel therapeutic strategies against disease progression that would enable the treatment of VEXAS patients at early disease stages, improving prognosis and life expectancy. Moreover, establishing robust genotype-to-phenotype correlations in patients may inform the design of personalized therapeutic options. The obtained results may inform the design of new therapeutic strategies against this cureless disease. Overall, in this observational monocentric study the investigators will use retrospective samples collected from 2020 to 2026 to conduct cytokine profiling and comprehensive omics-based characterization (transcriptomics, proteomics, metabolomics) on peripheral blood-derived monocytes/neutrophils and bone marrow (BM) hematopoietic cells.

Inclusion Criteria: * Patients with VEXAS syndrome: 1. Diagnosed with VEXAS syndrome by identification of pathogenic mutations in the UBA1 gene in hematopoietic cells isolated from peripheral blood in the presence of systemic autoinflammatory disease. 2. Age \>18. 3. BM and peripheral blood samples were collected between 2020 and 2026. * Healthy donors: 1. In good general health as evidenced by medical history, with no history of inflammatory or hematologic disorders. BM samples derive from subjetcs undergoing hip replacement. 2. Matched as closely as possible with VEXAS patients by age and sex. 3. Age \>18. 4. BM and peripheral blood samples were collected between 2020 and 2026. Exclusion Criteria: * Subjects not included in the previous criteria