Atypical splice site mutations causing VEXAS syndrome

VEXAS-Defining UBA1 Somatic Variants in 245,368 Diverse Individuals in the NIH All Of Us Cohort

OBJECTIVE

Somatic variants in UBA1 cause VEXAS, a recently described, systemic autoinflammatory disease. Research on VEXAS has largely focused on highly symptomatic patients. We sought to determine the prevalence of canonical, VEXAS-associated somatic variants and their disease penetrance in a diverse, unselected population.

METHODS

We analyzed clinical-grade whole genome sequencing data from 245,368 participants in the All of Us Research Program. We compared persons carrying a canonical VEXAS-associated somatic variant to age, sex, and ancestry matched controls across the domains of diagnoses, medications, and laboratory values.

RESULTS

74 participants were identified who carry one VEXAS-defining somatic variant, UBA1 c.121A>C, p.Met41Leu. The variant allele fraction ranged from 4.5% to 33%. No other canonical VEXAS-associated variants were identified. Of the 74 carriers, 62 (84%) were women, 20 (27%) were African American, and 14 (19%) were American Admixed/Latino. There was no statistically significant association between case/control status and any VEXAS-associated diagnosis code, medication prescription, or laboratory value.

CONCLUSION

We report the largest cohort to date of persons with the VEXAS-associated p.Met41Leu somatic variant. This cohort differed substantially from reported cohorts of patients with clinical VEXAS, having a higher proportion of persons who were young, female, and of diverse ancestry. Variant allele fractions were lower than reported in clinical VEXAS cohorts, and bioinformatic analysis detected no clinical manifestations of VEXAS. Thus, the UBA1 p.Met41Leu somatic variant displayed incomplete penetrance for VEXAS. Further study is needed to determine the natural history of VEXAS-associated somatic variants in the predisease phase.

Ocular and orbital manifestations in VEXAS syndrome

BACKGROUND

VEXAS (Vacuoles, E1 enzyme, X-linked, Autoinflammatory, Somatic) is a hematoinflammatory disease that typically affects adults. It results from a somatic mutation of the E1 ubiquitin conjugating enzyme encoded by the UBA1 gene. VEXAS is frequently accompanied by myelodysplastic syndrome (MDS). The purpose of this study is to describe the ocular and orbital manifestations of VEXAS patients in a case series in our medical centre.

METHODS

A retrospective chart review was performed for all patients who were diagnosed with VEXAS syndrome in a tertiary medical centre over two years.

RESULTS

Eight patients were identified with VEXAS. In six patients, the diagnosis was confirmed by genomic sequencing. Two patients were identified based on their phenotype. All patients were males. The mean age at diagnosis was 78.7 years. In two patients, the ocular manifestation was the presenting symptom for VEXAS. Seven patients (87.5%) had history of MDS. Systemic inflammation manifestations include: skin rash (n = 5), recurrent fevers (n = 2), relapsing polychondritis (n = 2), pleuritis and pleural effusion (n = 2), poly arteritis nodosa- PAN (n = 1) and thrombophlebitis (n = 1). Seven (87%) patients were presented with periorbital oedema. Three patients showed orbital inflammation. Dacryoadenitis was observed in two patients, and extraocular muscle (EOM) myositis was detected in two patients. Four patients demonstrated ocular inflammation such as: episcleritis, scleritis and anterior uveitis.

CONCLUSION

ocular manifestations in VEXAS include orbital inflammation, dacryoadenitis, myositis, uveitis, scleritis, episcleritis and periorbital oedema. We recommend that in old male patients, with history of haematological disorder, presenting with ocular symptom, VEXAS investigation should be taken into consideration.

VEXAS syndrome

VEXAS syndrome is a recently identified, adult-onset autoinflammatory disease caused by somatic mutations in UBA1. UBA1 is an X-linked gene encoding E1 ubiquitin activating enzyme and its mutation in hematopoietic stem and progenitor cells leads to their clonal expansion and myeloid-skewed differentiation. UBA1 mutations in VEXAS are clustered at the second methionine (p.Met41), eliminating UBA1b isoform translated from p.Met41. Loss of UBA1b impairs ubiquitination and activates innate immune pathways, leading to systemic autoinflammation manifested as recurrent fever, chondritis, pulmonary involvement, vasculitis, or neutrophilic dermatitis. VEXAS syndrome is frequently associated with hematological disorders such as myelodysplastic syndrome (MDS), plasma cell dyscrasia and venous thromboembolism. Macrocytic anemia/macrocytosis and vacuoles in myeloid/erythroid precursors are prominent features of VEXAS syndrome, and their presence in patients with autoinflammatory symptoms prompts physicians to screen for UBA1 variant. Treatment of VEXAS syndrome is challenging and no consistently effective therapies have been established. Anti-inflammation therapies including glucocorticoids and anti-interleukin-6 have shown limited efficacy, while azacytidine and JAK inhibitors such as ruxolitinib were found to induce favorable, mid-term responses. Hematopoietic stem cell transplantation is the only curative option for VEXAS and should be considered for younger, fit patients with poor prognostic factors or recalcitrant symptoms.

VEXAS syndrome: A new mimicker of idiopathic multicentric Castleman disease

INTRODUCTION

Idiopathic Multicentric Castleman Disease (iMCD) is a complex and poorly understood pathophysiological entity, which encompasses a variety of conditions and can mimic or be associated with autoimmune/autoinflammatory diseases, making it challenging to diagnose and treat. Vacuoles, Enzyme E1, X-linked, Autoinflammatory, Somatic (VEXAS) syndrome is an adult-onset autoinflammatory disorder associated with hematological abnormalities and caused by acquired somatic mutations in the ubiquitin-like modifier activating enzyme 1 gene (UBA1) which shares several common clinical and biological signs with iMCD. In this article, we report a patient with VEXAS syndrome initially presenting as iMCD, questioning the link between these two entities.

CASE DESCRIPTION

We report here a patient initially presenting as iMCD, proved on lymph node histology, which turns out to have a mutation at the splice acceptor site of exon 3 of UBA1 exhibiting VEXAS syndrome with Castleman-like lymph node.

CONCLUSION

This is only the second case of VEXAS syndrome presenting as iMCD. VEXAS syndrome should therefore be considered in the presence of iMCD suspicion, including in cases of compatible histology.

VEXAS syndrome: An update

VEXAS (Vacuoles, E1 Enzyme, X-linked, Autoinflammatory, Somatic) syndrome is a recently described autoinflammatory syndrome, mostly affecting men older than 50 years, caused by somatic mutation in the UBA1 gene, a X-linked gene involved in the activation of ubiquitin system. Patients present a broad spectrum of inflammatory manifestations (fever, neutrophilic dermatosis, chondritis, pulmonary infiltrates, ocular inflammation, venous thrombosis) and hematological involvement (macrocytic anemia, thrombocytopenia, vacuoles in myeloid and erythroid precursor cells, dysplastic bone marrow) that are responsible for a significant morbidity and mortality. The therapeutic management is currently poorly codified but is based on two main approaches: controlling inflammatory symptoms (by using corticosteroids, JAK inhibitor or tocilizumab) or targeting the UBA1-mutated hematopoietic population (by using azacitidine or allogeneic hematopoietic stem cell transplantation). Supportive care is also important and includes red blood cell or platelet transfusions, erythropoiesis stimulating agents, thromboprophylaxis and anti-infectious prophylaxis. The aim of this review is to provide a current overview of the VEXAS syndrome, particularly focusing on its pathophysiological, diagnostic and therapeutic aspects.

Vacuoles in bone marrow progenitors: VEXAS syndrome and beyond

The presence of vacuoles in myeloid and erythroid progenitor cells in bone marrow aspirates is a key feature of vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic (VEXAS) syndrome. The mere observation of vacuolated progenitor cells is not specific to VEXAS syndrome; in this Viewpoint, we point out the causes to be considered in this situation. Vacuoles, in particular, can be observed in individuals with wild-type UBA1 and with persistent inflammatory features or myelodysplastic syndromes. However, several clues support the diagnosis of VEXAS syndrome in the presence of vacuolated bone marrow progenitors: a high number of vacuolated progenitors and of vacuoles per cell, the predominance of vacuoles in early rather than late progenitors, and the vacuolisation of both myeloid and erythroid progenitors with predominance of myeloid ones. Some criteria derived from these observations have been proposed with great diagnostic performances. However, the absence or a low proportion of vacuolated cells should not prevent UBA1 gene sequencing.

VEXAS syndrome: Clinical, hematologic features and a practical approach to diagnosis and management

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.

VEXAS syndrome is characterized by inflammasome activation and monocyte dysregulation

Acquired mutations in the UBA1 gene were recently identified in patients with severe adult-onset auto-inflammatory syndrome called VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic). However, the precise physiological and clinical impact of these mutations remains poorly defined. Here we study a unique prospective cohort of VEXAS patients. We show that monocytes from VEXAS are quantitatively and qualitatively impaired and display features of exhaustion with aberrant expression of chemokine receptors. In peripheral blood from VEXAS patients, we identify an increase in circulating levels of many proinflammatory cytokines, including IL-1β and IL-18 which reflect inflammasome activation and markers of myeloid cells dysregulation. Gene expression analysis of whole blood confirms these findings and also reveals a significant enrichment of TNF-α and NFκB signaling pathways that can mediate cell death and inflammation. This study suggests that the control of the nflammasome activation and inflammatory cell death could be therapeutic targets in VEXAS syndrome.

VEXAS syndrome: Clinical manifestations, diagnosis, and treatment

VEXAS (Vacuoles, E1 enzyme, X-linked, Autoinflammatory, Somatic) syndrome is an adult-onset autoinflammatory syndrome characterized by somatic mutations in the UBA1 gene and is considered the prototype of hematoinflammatory diseases. Patients with VEXAS syndrome exhibit inflammatory and hematological manifestations that can lead to clinical diagnoses such as relapsing polychondritis, polyarteritis nodosa, Sweet syndrome, and myelodysplastic syndrome. Diagnosis requires bone marrow evaluation to identify cytoplasmic vacuoles in myeloid and erythroid precursors. However, genetic confirmation of mutations in UBA1 is necessary. Treatment is challenging and often involves glucocorticoids and immunosuppressants with variable responses. Hypomethylating agents and allogenic haemopoietic stem cell transplant are considered promising therapies. Prognosis is influenced by genetic and clinical factors. The aim of this review is to provide an overview of the pathogenesis, clinical presentation, treatment, and prognosis of VEXAS syndrome for the Latin American medical community.

Targeted testing of bone marrow specimens with cytoplasmic vacuolization to identify previously undiagnosed cases of VEXAS syndrome

OBJECTIVE

To retrospectively identify patients with VEXAS syndrome (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic syndrome) among male patients with bone marrow vacuolization using a clinically applicable, targeted-screening approach.

METHODS

Bone marrow reports from 1 May 2014 through 18 February 2022 were reviewed for documentation of cytoplasmic vacuolization. Patients with acute leukaemia, lymphoma, metastatic solid tumour, amyloidosis or POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes) syndrome were excluded, as were those without clinical records available for direct chart review. Cases were rated for suspicion of VEXAS syndrome using a 5-point scale based on the presence of laboratory findings, clinical features and treatment response. Patients with available DNA material and moderate (three patients) or high (four to five patients) suspicion were tested for somatic UBA1 variants associated with VEXAS syndrome.

RESULTS

A total of 315 reports from 292 unique patients included documentation of vacuolization. Following exclusion criteria, 64 patients underwent direct medical chart review to assess likelihood of VEXAS syndrome, for which 21 patients met moderate to high suspicion. Available DNA was present in eight patients, seven (87.5%) of whom had a pathogenic somatic UBA1 variant consistent with VEXAS syndrome. The distribution of cytoplasmic vacuolization in the bone marrow biopsy reports among patients with VEXAS syndrome were erythroid and myeloid precursors (6/7), erythroid precursors only (1/7) and myeloid precursors only (0/7).

CONCLUSION

In this study, the utilization of a clinically applicable targeted-screening approach to test bone marrow specimens (with vacuolization) for the presence of previously undiagnosed VEXAS syndrome resulted in a positive detection rate of 87.5%.

Spanish cohort of VEXAS syndrome: clinical manifestations, outcome of treatments and novel evidences about UBA1 mosaicism

BACKGROUND

The vacuoles, E1-enzyme, X linked, autoinflammatory and somatic (VEXAS) syndrome is an adult-onset autoinflammatory disease (AID) due to postzygotic UBA1 variants.

OBJECTIVES

To investigate the presence of VEXAS syndrome among patients with adult-onset undiagnosed AID. Additional studies evaluated the mosaicism distribution and the circulating cytokines.

METHODS

Gene analyses were performed by both Sanger and amplicon-based deep sequencing. Patients' data were collected from their medical charts. Cytokines were quantified by Luminex.

RESULTS

Genetic analyses of enrolled patients (n=42) identified 30 patients carrying UBA1 pathogenic variants, with frequencies compatible for postzygotic variants. All patients were male individuals who presented with a late-onset disease (mean 67.5 years; median 67.0 years) characterised by cutaneous lesions (90%), fever (66.7%), pulmonary manifestations (66.7%) and arthritis (53.3%). Macrocytic anaemia and increased erythrocyte sedimentation rate and ferritin were the most relevant analytical abnormalities. Glucocorticoids ameliorated the inflammatory manifestations, but most patients became glucocorticoid-dependent. Positive responses were obtained when targeting the haematopoietic component of the disease with either decitabine or allogeneic haematopoietic stem cell transplantation. Additional analyses detected the UBA1 variants in both haematopoietic and non-haematopoietic tissues. Finally, analysis of circulating cytokines did not identify inflammatory mediators of the disease.

CONCLUSION

Thirty patients with adult-onset AID were definitively diagnosed with VEXAS syndrome through genetic analyses. Despite minor interindividual differences, their main characteristics were in concordance with previous reports. We detected for the first time the UBA1 mosaicism in non-haematopoietic tissue, which questions the previous concept of myeloid-restricted mosaicism and may have conceptual consequences for the disease mechanisms.

VEXAS syndrome (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) for the dermatologist

In 2020, Beck et al1 described a novel adult autoinflammatory syndrome entitled VEXAS (Vacuoles, E1 enzyme, X-linked, Autoinflammatory, Somatic), a newly-discovered disorder that connected previously unrelated inflammatory syndromes and a prototype for a new class of hematoinflammatory diseases.2 Eighty-nine percent of published cases have documented skin involvement, but despite the high incidence and diagnostic accessibility of skin manifestations, there has been little focus on the dermatological features of VEXAS syndrome thus far. A PubMed search of all published case reports of VEXAS syndrome to date was performed, with inclusion of all cases confirmed by genetic sequencing, and this review summarizes the reported dermatological signs. There have already been 141 confirmed published cases since original publication, 126 of which had documented cutaneous signs.1-34 A wide range of skin presentations are reported, including Sweet-like urticated and tender erythematous nodules, cartilaginous involvement with chondritis, cutaneous vasculitis, and periorbital angiodema.1-34 Many patients had been diagnosed with Sweet syndrome, relapsing polychondritis, polyarteritis nodosa, or erythema nodosum.1-34 Hallmarks of skin histopathology are a neutrophilic dermatosis with coexisting or exclusive leukocytoclastic vasculitis.1 The new classification therefore helps link previously disparate inflammatory skin conditions into a unifying pathophysiological pathway.

Association Study Between Kynurenine 3-Monooxygenase (KMO) Gene and Parkinson's Disease Patients

The influence of various risk factors such as aging, intricate cellular molecular processes, and lifestyle factors like smoking, alcohol consumption, caffeine intake, and occupational factors has received increased focus in relation to the risk and development of Parkinson's disease (PD). Limited research has been conducted on the assessment of lifestyle impact on kynurenine 3-monooxygenase (KMO) gene in PD. A total of 164 subjects, including 82 PD cases and 82 healthy individuals, were recruited based on specific inclusion and exclusion criteria. The severity of PD and clinical assessment were evaluated using the Unified Parkinson's Disease Rating Scale (UPDRS) and Hoehn and Yahr (HY) scaling. Sanger sequencing was performed to analyse the KMO gene in the recruited subjects, and case-control studies were conducted. The UPDRS assessment revealed significant impairments in smell, tremors, walking, and posture instability in the late-onset PD cohorts. The HY scaling indicated a higher proportion of late-onset cohorts in stage 2. Moreover, both alcoholic and non-alcoholic groups showed significantly increased levels of 3-HK in late-onset PD. Gene analysis identified missense variants at position g.241593373 T > A (rs752312199) and intronic variants at positions g.241592623A > G (rs640718), g.241592800C > A (rs990388262), g.241592802A > C (rs1350160268), g.241592808 T > C (rs1478255936), and g.241592812G > T (rs948928931). The alterations in the KMO gene were found to influence the levels of kynurenic acid (KYNA) and 3-hydroxykynurenine (3-HK). Genomic analysis revealed a high prevalence of missense mutations in the late-onset PD groups, leading to a decline in 3-HK levels in patients. This leads to the reduction of the progression of disease in late-onset groups which shows that this mutation may lead to the protective effect on the PD subjects. This study suggests the use of KYNA and 3-HK as potential biomarkers in analysing the progression of disease. This study is limited by its small sample size. To overcome this limitation, a larger study involving in greater number of participants is needed to thoroughly investigate the KMO gene and KP metabolites, to enhance our understanding of Parkinson's disease progression, and to enhance diagnostic capabilities.

Recurrent superior orbital fissure syndrome associated with VEXAS syndrome

PURPOSE

To describe a case of recurrent orbital inflammation and superior orbital fissure syndrome associated with VEXAS (vacuoles, E1 enzyme, X-linked, auto-inflammatory, somatic) syndrome.

CASE PRESENTATION

VEXAS syndrome is a recently identified multi-system inflammatory disease of late adult onset. The authors describe the case of a 76-year-old man who presented with recurrent episodes of orbital inflammation, with superior orbital fissure syndrome, dacryoadenitis and orbital myositis. He had a constellation of systemic disorders including recurrent chest infections, congestive cardiac failure, pulmonary emboli and skin rashes. The underlying diagnosis of VEXAS syndrome was confirmed by genetic testing, which revealed the UBA1 mutation.

CONCLUSION

VEXAS syndrome should be considered in the differential diagnosis of orbital inflammatory disease associated with multi-system inflammatory disorders.

VEXAS Syndrome-Review

VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is a newly defined refractory adult-onset autoinflammatory syndrome caused by somatic mutations in the ubiquitin-like modifier-activating enzyme 1 (UBA1) gene in hematopoietic stem and progenitor cells, resulting in a shift in UBA1 isoform expression. Thus, patients develop a spectrum of systemic inflammatory manifestations and hematologic symptoms. To date, patients respond poorly to immune suppressive drugs, except high-dose glucocorticoids, and no treatment guidelines have been established. Given the high mortality rate, VEXAS syndrome needs to be taken seriously by physicians in all specialties. This article aims to describe the key features, pathogenesis, and clinical manifestations of VEXAS syndrome to better understand the targeted treatment and improve the prognosis of VEXAS syndrome.

Early activation of inflammatory pathways in UBA1-mutated hematopoietic stem and progenitor cells in VEXAS

VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is a pleiotropic, severe autoinflammatory disease caused by somatic mutations in the ubiquitin-like modifier activating enzyme 1 (UBA1) gene. To elucidate VEXAS pathophysiology, we performed transcriptome sequencing of single bone marrow mononuclear cells and hematopoietic stem and progenitor cells (HSPCs) from VEXAS patients. HSPCs are biased toward myeloid (granulocytic) differentiation, and against lymphoid differentiation in VEXAS. Activation of multiple inflammatory pathways (interferons and tumor necrosis factor alpha) occurs ontogenically early in primitive hematopoietic cells and particularly in the myeloid lineage in VEXAS, and inflammation is prominent in UBA1-mutated cells. Dysregulation in protein degradation likely leads to higher stress response in VEXAS HSPCs, which positively correlates with inflammation. TCR usage is restricted and there are increased cytotoxicity and IFN-γ signaling in T cells. In VEXAS syndrome, both aberrant inflammation and myeloid predominance appear intrinsic to hematopoietic stem cells mutated in UBA1.

Accurate stratification between VEXAS syndrome and differential diagnoses by deep learning analysis of peripheral blood smears

OBJECTIVES

VEXAS syndrome is a newly described autoinflammatory disease associated with UBA1 somatic mutations and vacuolization of myeloid precursors. This disease possesses an increasingly broad spectrum, leading to an increase in the number of suspected cases. Its diagnosis via bone-marrow aspiration and UBA1-gene sequencing is time-consuming and expensive. This study aimed at analyzing peripheral leukocytes using deep learning approaches to predict VEXAS syndrome in comparison to differential diagnoses.

METHODS

We compared leukocyte images from blood smears of three groups: participants with VEXAS syndrome (identified UBA1 mutation) (VEXAS); participants with features strongly suggestive of VEXAS syndrome but without UBA1 mutation (UBA1-WT); participants with a myelodysplastic syndrome and without clinical suspicion of VEXAS syndrome (MDS). To compare images of circulating leukocytes, we applied a two-step procedure. First, we used self-supervised contrastive learning to train convolutional neural networks to translate leukocyte images into lower-dimensional encodings. Then, we employed support vector machine to predict patients' condition based on those leukocyte encodings.

RESULTS

The VEXAS, UBA1-WT, and MDS groups included 3, 3, and 6 patients respectively. Analysis of 33,757 images of neutrophils and monocytes enabled us to distinguish VEXAS patients from both UBA1-WT and MDS patients, with mean ROC-AUCs ranging from 0.87 to 0.95.

CONCLUSIONS

Image analysis of blood smears via deep learning accurately distinguished neutrophils and monocytes drawn from patients with VEXAS syndrome from those of patients with similar clinical and/or biological features but without UBA1 mutation. Our findings offer a promising pathway to better screening for this disease.

VEXAS syndrome: a newly discovered systemic rheumatic disorder

VEXAS syndrome is an adult-onset autoinflammatory disease associated with hematologic symptoms. The disease affects primarily males, and leads to death of a significant proportion of the patients. VEXAS syndrome is caused by a somatic mutation of the UBA1 gene in hematopoietic progenitor cells. The clinical picture of the syndrome consists of a number of organ manifestations including those akin to rheumatic diseases, arthritis, myalgia, vasculitis and chondritis.

VEXAS: where do we stand 2 years later?

PURPOSE OF REVIEW

Two years after the recognition of VEXAS (for Vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome, we propose an extensive review of the current understanding of VEXAS pathophysiology and therapeutic options.

RECENT FINDINGS

Among the nearly 150 articles published about VEXAS, some have provided determinant insights into VEXAS pathophysiology and treatment. Clinical data from retrospective series support the JAK inhibitor ruxolitinib as the most efficient strategy to control inflammation, and interesting results were also described with azacytidine. Allogeneic stem cell transplantation remains the only curative option, but should be proposed to carefully selected patients.

SUMMARY

Although waiting for more robust evidence from prospective clinical trials, therapeutic options emerge from retrospective studies. We propose a set of criteria that should be systematically reported to harmonize the evaluation of therapeutic outcomes. This will allow the collection of high-quality data and facilitate their subsequent meta-analysis with the overall aim of improving the management of VEXAS patients.

VEXAS syndrome: A review of bone marrow aspirate and biopsies reporting myeloid and erythroid precursor vacuolation

Myeloid and erythroid precursor vacuolation is a common dysplastic finding associated with myeloid malignancies, toxins, drug, and nutritional deficiencies. It has been described as a core morphologic feature in VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome. We sought to determine the number of cases attributable to VEXAS syndrome in bone marrow biopsies and aspirates (BAMB) reporting myeloid precursor vacuolation. We reviewed 1318 individual BAMB reports from January 2020 to July 2021 where "vacuole(s)," "vacuolation," or "vacuolated" was reported. Bone marrow biopsies with vacuolation confined to blasts or those completed as routine workup prior to stem cell transplant or post induction chemotherapy for AML (acute myeloid leukemia) were excluded. Myeloid and erythroid precursor vacuolation was noted in 219 reports representing 210 patients. The most common etiology was myelodysplastic syndrome (MDS) (38.6%), AML (16.7%), lymphoproliferative disorders and multiple myeloma (7.6%), drug or toxin exposure (5.2%) myeloproliferative neoplasm (MPN) or MPN/MDS overlap syndrome (4.3%). VEXAS syndrome was determined to be the etiology in 2.9% of patients. Two additional cases of VEXAS syndrome with bone marrow biopsies reported in the specified time frame did not explicitly report myeloid or erythroid precursor vacuolation but were identified based on clinical suspicion and repeat BAMB review. Myeloid and erythroid precursor vacuolation is a dysplastic feature attributable to VEXAS syndrome in at least 2.9% of cases. Standardized reporting of vacuolization, triaging of molecular sequencing and optimal treatment of this disorder are critical issues facing those seeing patients with suspected VEXAS syndrome.

An update on VEXAS syndrome

INTRODUCTION

VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is a recently described, late-onset, acquired autoinflammatory disorder caused by mutations in the UBA1 gene. The various clinical manifestations of VEXAS broadly divided into inflammatory or haematological. VEXAS defines a new disease category - the hematoinflammatory disorders triggered by somatic mutations restricted to blood but causing systemic inflammation with multi-organ involvement and associated with aberrant bone marrow status. VEXAS causes significant morbidity and reduced life expectancy, but the optimum standard of care remains undefined.

AREAS COVERED

This review describes the discovery of VEXAS, relevant genetic causes and immunopathology of the disease. A detailed account of its various clinical manifestations and disease mimics is provided. Current treatment and management options are discussed.

EXPERT OPINION

New rare variants in UBA1 and VEXAS-like UBA1 negative cases are reported. Consensus diagnostic criteria might be required to define VEXAS and its related disorders. Investigation of sporadic, VEXAS-like cases will require the application of deep sequencing using DNA obtained from various cellular or tissue locations. Prospective studies are needed to define the optimal supportive and treatment options for patients with varying disease severity and prognosis. VEXAS-specific hematopoietic stem cell transplant selection criteria also require development.

Paradigm shift in monogenic autoinflammatory diseases and systemic vasculitis: The VEXAS syndrome

VEXAS syndrome was described by the end of 2020 as an autoinflammatory disease caused by post-zygotic variants in the UBA1 gene. VEXAS syndrome occurs in adult males with recurrent fever, arthralgia/arthritis, ear/nose chondritis, neutrophilic dermatosis, lung inflammation, venous thrombosis, and different types of vasculitis. Common laboratory changes include raised acute phase reactants and macrocytic anemia. The coexistence of myelodysplasia is frequent, and bone marrow vacuolization of myeloid and erythroid precursors is characteristic. Glucocorticoids are effective at medium-high doses, but the remaining immunosuppressive drugs, either conventional or biological, have showed limited or absent efficacy. Azacitidine has been associated with a good response, especially in patients with accompanying myelodysplastic syndrome. Allogeneic hematopoietic stem cell transplantation appears to be the only curative therapy by now. VEXAS syndrome has become a paradigm shift in the diagnosis and treatment of autoinflammatory diseases and systemic vasculitis.

Update on VEXAS and role of allogeneic bone marrow transplant: Considerations on behalf of the Chronic Malignancies Working Party of the EBMT

VEXAS (acronym for Vacuoles, E1 enzyme, X-linked, Autoinflammatory, Somatic) is a fascinating new entity encompassing a variety of clinical manifestations, spanning from auto-inflammatory symptoms to hematologic disorders, including myelodysplastic syndromes and plasma cell dyscrasias. Genetically defined by somatic mutations of the X-linked gene UBA1 in hematopoietic stem and progenitor cells, VEXAS typically manifests in males during the fifth/sixth decade of life. Since its discovery, several groups have documented pleomorphic clinical phenotypes, in addition to a plethora of therapeutic options (e.g., JAK inhibitors, hypomethylating agents, and allogeneic stem cell transplant, allo-HCT) in retrospective case series. However, no treatment guidelines have been validated to date, VEXAS patients are typically steroid-dependent and may manifest life-threatening inflammatory symptoms refractory to multiple lines of therapy. To date, the only curative option appears to be allo-HCT in suitable individuals. Nonetheless, this procedure carries an inherent risk of morbidity and mortality that must be judiciously evaluated against a phenotypically diverse disorder where the optimal therapeutic algorithm remains ill-defined. Herein, we provide an overview of the current VEXAS data/ therapeutic evidence and discuss the curative potential of allo-HCT whilst highlighting the efforts required for generation of robust data able to inform therapeutic decisions.

VEXAS Syndrome: A Novelty in MDS Landscape

Fever, inflammation and vacuoles in hematopoietic cells represent the main features associated with VEXAS syndrome, a new prototype of autoinflammatory disorders genetically characterized by somatic mutation of the UBA1 gene which encodes the enzyme1-activating enzyme (E1) required for ubiquitin signaling. Described very recently, patients with VEXAS syndrome present a systemic autoinflammatory syndrome associated with hematological impairments, especially cytopenias whose pathophysiology is mainly non-elucidated. Initially diagnosed in elderly male patients, VEXAS syndrome was frequently associated with a diagnosis of myelodysplastic syndromes (MDS) leading the medical community to first consider VEXAS syndrome as a new subtype of MDS. However, since the first description of VEXAS patients in 2021, it appears from the multitude of case reports that MDS associated with VEXAS are different from the classically described MDS.

Characteristic bone marrow findings in patients with UBA1 somatic mutations and VEXAS syndrome

VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) is a newly characterized syndrome with underlying somatic UBA1 mutations in myeloid cells linking hematologic disease with autoinflammatory rheumatologic disorders. Hematologic abnormalities, particularly peripheral blood cytopenia(s) may prompt bone marrow evaluation in patients with known or unrecognized VEXAS syndrome. This review highlights key findings and diagnostic considerations encountered during bone marrow examination in patients with this disorder. Frequently reported hematologic changes include macrocytic anemia, cytoplasmic vacuoles in myeloid and erythroid precursors, marrow hypercellularity, and varying degrees of dysplasia. Myelodysplastic syndrome and plasma cell neoplasms have been diagnosed in patients with VEXAS syndrome. Macrophage activation syndrome and/or hemophagocytic lymphohistiocytosis and monoclonal B-cell lymphocytosis have also been reported. The bone marrow is a target organ in VEXAS syndrome. Heightened awareness of the bone marrow features and hematologic complications may aid in identifying individuals with VEXAS who may benefit from increased disease surveillance or alternative therapeutic strategies.

Genetics of somatic auto-inflammatory disorders

Systemic autoinflammatory disorders (SAIDs) encompass a heterogeneous group of monogenic disorders characterized by recurrent episodes of systemic and organ-specific inflammation. Genetic studies have facilitated the identification of Mendelian forms of SAIDs but many patients still remain without a diagnosis. Recent studies have uncovered that somatic (acquired) mutations can cause later-onset SAIDs. In this review, we will discuss the current knowledge surrounding the genetics of these acquired auto-inflammatory disorders (AAIDs), with a focus on VEXAS, NLRP3-associated AAIDs and Schnitzler's syndrome and provide suggestions for future research in this field.

Clonal hematopoiesis and VEXAS syndrome: survival of the fittest clones?

Clonal hematopoiesis (CH) is defined by the acquisition of somatic mutations in hematopoietic stem cells (HSC) leading to enhanced cellular fitness and proliferation under positive clonal selection pressures. CH most frequently involves epigenetic regulator genes (DNMT3A, TET2 and ASXL1), with these mutations being associated with enhanced inflammation and increased all-cause mortality largely from cardiovascular disease and endothelial dysfunction. These mutations also increase the risk for hematological neoplasms. Somatic mutations in UBA1, encoding the E1 ubiquitin ligase in HSC, cause a severe adult-onset autoinflammatory disease that can be associated with myeloid and plasma cell neoplasms, termed VEXAS (vacuoles, X-linked, autoinflammatory, somatic) syndrome. Given the degree of inflammation seen, one would have expected this to be a fertile ground for CH development and propagation, however, preliminary data doesn't support this. Here in, we review the current data on CH, inflammation and VEXAS syndrome.