Warrington, Kenneth J.

Abstract Objectives VEXAS syndrome is an adult-onset autoinflammatory disease caused by a somatic pathogenic mutation in the UBA1 (ubiquitin-like modifier activating enzyme 1) gene. Patients present with rheumatologic manifestations and cytopenias and may have an increased predisposition to myelodysplastic syndrome (MDS) and plasma cell neoplasms. Prior studies have reported on the peripheral blood and bone marrow findings in patients with VEXAS syndrome. Due to the protean clinical presentation and lack of specificity of morphologic features (eg, vacuoles in early erythroid and granulocytic precursors), an optimal screening methodology to identify these patients in a timely fashion is desirable. Methods To further evaluate and describe the salient diagnostic morphologic features in VEXAS syndrome, we carried out a comprehensive study of the largest single-institution cohort to date. Diagnostic and follow-up bone marrow biopsy specimens from 52 male patients with molecularly identified VEXAS syndrome underwent central review. Results Cytopenias were common in all cases, primarily macrocytic anemia, monocytopenia, and thrombocytopenia. Bone marrow aspirate and biopsy were often hypercellular, with an increased myeloid/erythroid ratio, granulocytic hyperplasia with left shift, erythroid left shift, and megakaryocyte hyperplasia, which exhibited a range of striking morphologic findings. Distinctly vacuolated myeloid and erythroid precursors were seen in more than 95% of cases. Conclusions Our data reveal potential novel diagnostic features, such as a high incidence of monocytopenia and distinct patterns of atypical megakaryopoiesis, that appear different from dysmegakaryopoiesis typically associated with MDS. In our experience, those findings are suggestive of VEXAS, in the appropriate clinical context.

Abstract VEXAS (Vacuoles, E1 enzyme, X‐linked, Autoinflammatory, Somatic) syndrome is a newly identified disease caused by somatic alterations in UBA1 which produce a recalcitrant inflammatory state along with hematologic disturbances. Patients with VEXAS can have a wide spectrum of clinical symptoms and providers should be familiar with the heterogeneity of associated clinical features. While hematologic parameters may be generally non‐specific, peripheral blood features of macrocytosis, monocytopenia, and/or thrombocytopenia coupled with bone marrow vacuolization of erythroid or myeloid precursors should raise suspicion for this condition. Due to an increased mortality, prompt recognition and accurate diagnosis is paramount. Access to testing for confirmation of UBA1 variants is not yet universally available but clinicians should understand the current available options for genetic confirmation of this disease. Treatment options are limited due to lack of prospective clinical trials but cytokine directed therapies such as interleukin‐6 inhibitors and JAK–STAT inhibitors as well as hypomethylating agents such as azacitidine have shown evidence of partial effect. Though cases are limited, allogeneic stem cell transplantation holds promise for durable response and potential cure. The intent of this review is to outline the pathophysiology of VEXAS syndrome and to provide a practical approach to diagnosis and treatment.

Giant cell arteritis (GCA) and Takayasu arteritis (TAK) are large-vessel vasculitides affecting the aorta and its branches. Arterial damage from these diseases may result in ischemic complications, aneurysms, and dissections. Despite their similarities, the management of GCA and TAK differs. Glucocorticoids are used frequently but relapses are common, and glucocorticoid toxicity contributes to significant morbidity. Conventional immunosuppressive therapies can be beneficial in TAK, though their role in the management of GCA remains unclear. Tumor necrosis factor inhibitors improve remission rates and appear to limit vascular damage in TAK; these agents are not beneficial in GCA. Tocilizumab is the first biologic glucocorticoid-sparing agent approved for use in GCA and also appears to be effective in TAK. A better understanding of the pathogenesis of both conditions and the availability of targeted therapies hold much promise for future management.

Autoimmune vasculitis of the medium and large elastic arteries can cause blindness, stroke, aortic arch syndrome, and aortic aneurysm. The disease is often refractory to immunosuppressive therapy and progresses over decades as smoldering aortitis. How the granulomatous infiltrates in the vessel wall are maintained and how tissue-infiltrating T cells and macrophages are replenished are unknown. Single-cell and whole-tissue transcriptomic studies of immune cell populations in vasculitic arteries identified a CD4 + T cell population with stem cell–like features. CD4 + T cells supplying the tissue-infiltrating and tissue-damaging effector T cells survived in tertiary lymphoid structures around adventitial vasa vasora, expressed the transcription factor T cell factor 1 (TCF1), had high proliferative potential, and gave rise to two effector populations, Eomesodermin (EOMES) + cytotoxic T cells and B cell lymphoma 6 (BCL6) + T follicular helper-like cells. TCF1 hi CD4 + T cells expressing the interleukin 7 receptor (IL-7R) sustained vasculitis in serial transplantation experiments. Thus, TCF1 hi CD4 + T cells function as disease stem cells and promote chronicity and autonomy of autoimmune tissue inflammation. Remission-inducing therapies will require targeting stem-like CD4 + T cells instead of only effector T cells.

Abstract Objectives ANCA-associated vasculitis (AAV) is currently categorized under the small vessel vasculitides. There is limited knowledge about large vessel involvement in AAV (L-AAV), mainly described in case reports and small series. L-AAV can involve temporal arteries (TA-AAV), aorta (A-AAV), and periaortic soft tissue (PA-AAV). We sought to characterize the features of patients with L-AAV. Methods Patients older than 18 years at diagnosis of TA-AAV, A-AAV and PA-AAV seen at the Mayo Clinic, Rochester between 1 January 2000 and 31 December 2021 were identified through a proprietary medical text search algorithm. Patients were included if diagnosed with L-AAV, fulfilled 2022 ACR/EULAR classification criteria for GPA, MPA or EGPA, had positive ANCA test results, and had more than one outpatient or inpatient visit. Results The study cohort consists of 36 patients with L-AAV. Of those, 23 had p-ANCA and/or MPO-ANCA, and 13 had c-ANCA and/or PR3-ANCA. Mean (s.d.) age at AAV diagnosis was 63.4 (12.79) years; 20 (56%) were male. Seventeen patients had TA-AAV, 10 had A-AAV and 9 had PA-AAV. Most patients (n = 25, 69%) were diagnosed with large vessel vasculitis and AAV within a 1-year timespan. Twenty-five (69%) patients had histopathological confirmation of AAV diagnosis in a location other than temporal artery, aorta or periaortic soft tissue. Glucocorticoids (36/36), rituximab (19/36) and methotrexate (18/36) were the most frequent treatments. Conclusion This is the largest single-centre cohort of patients with L-AAV to date. AAV can involve large arteries, albeit infrequent. AAV-targeted therapy should be considered in patients with L-AAV.