VEXAS (Vacuoles, E1 enzyme, X-linked, Autoinflammatory, Somatic) syndrome is an acquired, late-onset disorder, almost exclusively described in male patients. This new clinical entity is associated with autoinflammation and haematological abnormalities, such as Myelodysplastic Syndrome, Monoclonal Gammopathy of Undetermined Significance (MGUS) and Multiple Myeloma (MM). Common laboratory abnormalities are chronic inflammation, macrocytic anaemia, thrombocytopenia and lymphopenia. The diagnosis is genotype-based by the identification of myeloid-restricted somatic mutations in the UBA1 gene, exclusively found on the X-chromosome. A bone marrow aspirate and trephine biopsy are crucial in the diagnostic work-up, demonstrating the typical finding of vacuoles. Clear scientific support comparing different treatment strategies in VEXAS syndrome is still lacking. Currently, corticosteroid treatment remains the cornerstone in the control of inflammatory flare-ups. Corticosteroid-sparing regimens such as methotrexate, tumour necrosis factor inhibitors, anti-interleukine-6, and anti-interleukine-1 agents have only been able to demonstrate a short-term response. While an allogeneic haematopoietic stem cell transplantation (allo-HSCT) seems to be the only long-lasting curative treatment to eradicate the causing pathogenic UBA1 clones, ideal candidate selection and timing for allo-HSCT remain unclear. Recently, some case reports have demonstrated promising results when integrating the use of hypomethylating agents or ruxolitinib in the treatment of patients with VEXAS syndrome. As VEXAS syndrome remains a fatal disease with a mean 5-year mortality of up to 40%, clinicians should be aware of its existence, clinical work-up and possible treatment strategies.

(BELG J HEMATOL 2023;14(6):236–44)