Joint involvement in VEXAS and non-VEXAS clonal haematopoiesis: two clusters from a multicentre regional cohort

To describe the joint manifestations associated with clonal haematopoiesis and to compare patients with and without VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome.

Patients screened for UBA1 mutations between December 2019 and January 2023 in 7 Normandie (France) hospitals were recruited retrospectively.

Thirty patients with a haematological disorder associated with dysimmune manifestations were included: 17 (57%) without UBA1 mutations (non-VEXAS) and 13 (43%) with UBA1 mutations (VEXAS). Thirteen (77%) non-VEXAS patients had joint involvement (arthralgia/arthritis), compared with 4 (31%) VEXAS patients (p value: 0.016). Unsupervised clustering using hierarchical clustering identified two clusters. Cluster 1 (14 patients) had more joint involvement (93% vs 25%, p value: 0.001), less UBA1 mutation (14% vs 69%, p value: 0.008), pulmonary involvement (7% vs 50%, p value: 0.017), chondritis (0% vs 50%, p value: 0.003) and unprovoked venous thrombosis (7% vs 43%, p value: 0.039) than cluster 2 (16 patients). Cluster 1 had more ASXL1 mutations (21% vs 0%).

Joint involvement was more frequent in patients with clonal haematopoiesis and dysimmune manifestations unrelated to VEXAS syndrome.