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.

Invasive group A streptococcal infections requiring admission to ICU: a nationwide, multicenter, retrospective study (ISTRE study)

BACKGROUND

Group A Streptococcus is responsible for severe and potentially lethal invasive conditions requiring intensive care unit (ICU) admission, such as streptococcal toxic shock-like syndrome (STSS). A rebound of invasive group A streptococcal (iGAS) infection after COVID-19-associated barrier measures has been observed in children. Several intensivists of French adult ICUs have reported similar bedside impressions without objective data. We aimed to compare the incidence of iGAS infection before and after the COVID-19 pandemic, describe iGAS patients' characteristics, and determine ICU mortality associated factors.

METHODS

We performed a retrospective multicenter cohort study in 37 French ICUs, including all patients admitted for iGAS infections for two periods: two years before period (October 2018 to March 2019 and October 2019 to March 2020) and a one-year after period (October 2022 to March 2023) COVID-19 pandemic. iGAS infection was defined by Group A Streptococcus isolation from a normally sterile site. iGAS infections were identified using the International Classification of Diseases and confirmed with each center's microbiology laboratory databases. The incidence of iGAS infections was expressed in case rate.

RESULTS

Two hundred and twenty-two patients were admitted to ICU for iGAS infections: 73 before and 149 after COVID-19 pandemic. Their case rate during the period before and after COVID-19 pandemic was 205 and 949/100,000 ICU admissions, respectively (p < 0.001), with more frequent STSS after the COVID-19 pandemic (61% vs. 45%, p = 0.015). iGAS patients (n = 222) had a median SOFA score of 8 (5-13), invasive mechanical ventilation and norepinephrine in 61% and 74% of patients. ICU mortality in iGAS patients was 19% (14% before and 22% after COVID-19 pandemic; p = 0.135). In multivariate analysis, invasive mechanical ventilation (OR = 6.08 (1.71-21.60), p = 0.005), STSS (OR = 5.75 (1.71-19.22), p = 0.005), acute kidney injury (OR = 4.85 (1.05-22.42), p = 0.043), immunosuppression (OR = 4.02 (1.03-15.59), p = 0.044), and diabetes (OR = 3.92 (1.42-10.79), p = 0.008) were significantly associated with ICU mortality.

CONCLUSION

The incidence of iGAS infections requiring ICU admission increased by 4 to 5 after the COVID-19 pandemic. After the COVID-19 pandemic, the rate of STSS was higher, with no significant increase in ICU mortality rate.

Pleuropulmonary Manifestations of Vacuoles, E1 Enzyme, X-Linked, Autoinflammatory, Somatic (VEXAS) Syndrome

BACKGROUND

The vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic (VEXAS) syndrome is a newly identified autoinflammatory disorder related to somatic UBA1 mutations. Up to 72% of patients may show lung involvement.

RESEARCH QUESTION

What are the pleuropulmonary manifestations in VEXAS syndrome?

STUDY DESIGN AND METHODS

One hundred fourteen patients were included in the French cohort of VEXAS syndrome between November 2020 and May 2021. Each patient included in the study who had an available chest CT scan was discussed in an adjudication multidisciplinary team and classified as showing potentially pleuropulmonary-specific involvement of VEXAS syndrome or others.

RESULTS

Fifty-one patients had a CT scan available for review and 45 patients (39%) showed pleuropulmonary abnormalities on chest CT scan that were considered related to VEXAS syndrome after adjudication. Most patients were men (95%) with a median age 67.0 years at the onset of symptoms. Among these 45 patients, 44% reported dyspnea and 40% reported cough. All 45 patients showed lung opacities on chest CT scan (including ground-glass opacities [87%], consolidations [49%], reticulation [38%], and septal lines [51%]) and 53% of patients showed pleural effusion. Most patients showed improvement with prednisone, but usually required > 20 mg/d. The main clinical and biological features as well the median survival did not differ between the 45 patients with pleuropulmonary involvement and the rest of the cohort, suggesting that the prevalence of pleuropulmonary involvement might have been underdiagnosed in the rest of the cohort.

INTERPRETATION

Pulmonary manifestations are frequent in VEXAS syndrome, but rarely are at the forefront. The initial outcome is favorable with prednisone and does not seem to lead to pulmonary fibrosis.

POS0141 PLATELET-SELECTIN PRIME LUPUS NEUTROPHILS TO PRODUCE MITOCHONDRIAL ROS AND PARTICIPATE IN SLE PATHOGENESIS

Background

In patients with active systemic lupus erythematosus (SLE), circulating platelets have an activated phenotype characterized by the expression of P-selectin (CD62P). We have shown that in human SLE, platelets interact with T regulatory cells and repress their immunosuppressive functions through a P-selectin/CD15s-dependent interaction (1). Preliminary results showed that neutrophils express high level of CD15s, predicting a possible platelet/neutrophil interaction in SLE.

Objectives

Investigate platelet/neutrophils interaction in human SLE and evaluate its impact on neutrophil functions, and lupus pathogenesis.

Methods

Patients with SLE responding to the 2019 ACR/EULAR criteria were recruited for blood sampling (n = 30). Disease activity was measured using SLE disease activity index (SLEDAI-2K), and patients were considered active if SLEDAI-2K ≥ 6. Platelet-neutrophils aggregates were identified as (platelet) CD61+ (neutrophil) CD66b+ cells using flow cytometry on fresh blood samples. Single-cell cytosolic calcium and ROS imaging was performed by incubating cell with either a fluorescent calcium dye (cali-520), or a mitochondrial specific dye (MitoSox). Coverslips were mounted in an Attofluor cell chamber positioned on the stage of an inverted epifluorescence microscope (Olympus, IX70). Mitochondrial polarization of human neutrophil was evaluated by incubating cells with TMRM (100 nM) for 30 minutes. Platelet-free plasma was isolated by two sequential centrifugations (3500xg) of EDTA-anticoagulated blood and stored for subsequent evaluation of soluble P-selectin (using ELISA) and (platelet-derived) microparticular P-selectin (using flow cytometry).

Results

In healthy donors (HD) and patients with SLE, circulating neutrophils expressed significantly higher levels of the P-selectin ligand CD15s compared to lymphoid subsets (p < 0.001), predicting platelet/neutrophil interactions. In contrast to HD and patients with inactive SLE, those with active disease had a significant increase of circulating platelet-neutrophils aggregates (p < 0.05), and these aggregates correlated with the SLEDAI (r = 0.59, p < 0.001). The incubation of human neutrophils with recombinant P-selectin induced a strong intracellular calcium signaling which was inhibited by preincubating neutrophil with anti-PSGL1 antibody (blocking P-selectin/CD15s interaction) or with a Syk kinase inhibitor. Similarly, P-selectin induced a mitochondrial ROS release in a CD15s- and Syk-dependent manner. Interestingly, incubation of neutrophils with anti-dsDNA IgG and P-selectin induced mitochondrial depolarization, which was absent with either stimulus alone. Soluble and platelet-derived microparticular P-selectin levels were significantly increased in patients with active SLE compared to inactive patients or healthy donors (p < 0.05 and p < 0.001, respectively). In a longitudinal analysis of SLE patients, soluble and microparticular P-selectin levels closely followed clinical (SLEDAI) and biological (C3 levels) markers of SLE disease activity.

Conclusion

P-selectin levels are increased in active SLE and follow hallmark of disease activity. P-selectin induces calcium/mitochondrial ROS signaling in lupus neutrophils which are key players in SLE pathogenesis. We hypothesize that the inhibition of P-selectin pathway might be a promising target in SLE.

References

[1]Scherlinger M. et al. (2021), Science Translational Medicine, 13(600):eabi4994.

Disclosure of Interests

None declared

Central Nervous System Cryptococcosis in Patients With Sarcoidosis: Comparison With Non-sarcoidosis Patients and Review of Potential Pathophysiological Mechanisms

Introduction

Cryptococcus spp. infection of the central nervous system (CINS) is a devastating opportunistic infection that was historically described in patients with acquired immunodeficiency syndrome (AIDS). Cryptococcus spp. infections are also associated with sarcoidosis; the impairment of cell-mediated immunity and long-term corticosteroid therapy being evoked to explain this association. Nevertheless, this assertion is debated and the underlying pathophysiological mechanisms are still unknown. The aims of this study were (i) to describe the clinical and biological presentation, treatments, and outcomes of CINS patients with and without sarcoidosis and (ii) to review the pathophysiological evidence underlying this clinical association.

Patients and Methods

Every patient with positive cerebrospinal fluid (CSF) cryptococcal antigen testing, India ink preparation, and/or culture from January 2015 to December 2020 at a tertiary university hospital were included, and patients with sarcoidosis were compared with non-sarcoidosis patients. Quantitative variables are presented as mean ± SD and are compared using the Mann-Whitney Wilcoxon rank-sum test. Categorical variables are expressed as the number of patients (percentage) and compared using the χ² or Fisher's tests.

Results

During the study period, 16 patients experienced CINS, of whom 5 (31%) were associated with sarcoidosis. CINS symptoms, biological, and CSF features were similar between CINS patients with and without sarcoidosis except regarding CD4 cells percentages and CD4/CD8 ratio that was higher in those with sarcoidosis (47 ± 12 vs. 22 ± 18, p = 0.02 and 2.24 ± 1.42 vs. 0.83 ± 1.10, p = 0.03, respectively). CINS patients with sarcoidosis had less often positive blood antigen testing than those without sarcoidosis (2/5 vs. 11/11, p = 0.02). CINS patients with and without sarcoidosis were treated with similar drugs, but patients with sarcoidosis had a shorter length of treatment. CD4 cell levels do not seem to explain the association between sarcoidosis and cryptococcosis.

Conclusion

Sarcoidosis was the most frequently associated condition with CINS in this study. CINS patients associated with sarcoidosis had overall similar clinical and biological presentation than CINS patients associated with other conditions but exhibited a lower rate of positive blood cryptococcal antigen testing and higher CD4/CD8 T cells ratio. Pathophysiological mechanisms underlying this association remain poorly understood but B-1 cell deficiency or lack of IgM could be a part of the explanation. Another plausible mechanism is the presence of anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) antibodies in a subset of patients with sarcoidosis, which could impair macrophage phagocytic function. Further studies are strongly needed to better understand those mechanisms and to identify at-risk patients.

An unexpected case of Borrelia garinii liver infection

Background

Lyme borreliosis is the most prevalent arthropod-borne infection in the Northern Hemisphere. In Europe, Borrelia afzelii is predominantly involved in cutaneous manifestations, Borrelia garinii and Borrelia bavariensis in neurological manifestations, and Borrelia burgdorferi sensu stricto in articular ones. Liver impairement is not classical in Lyme borreliosis. Diagnosis is currently mainly based on serological testing, and is challenging in immunocompromised patients.

Case presentation

We report the first case of B. garinii infection revealed by liver involvement in an immunocompromised man. A 73-year-old man with marginal zone lymphoma, treated with bendamustine and rituximab, developed intermittent fever and inflammatory syndrome. Microbial investigations were all negative and FDG-PET showed complete remission of the lymphoma. Three months later, liver biopsy was performed and histology revealed spirochetes-like bacteria. Microbial diagnosis was performed by 16S rDNA sequencing, flagellin (flaB) gene sequencing and multi-locus sequence typing and identified B. garinii. The patient recovered successfully after a three weeks course of antibiotics. Diagnosis was challenging because Borrelia hepatic involvement is unusual and no erythema migrans nor tick bite were notified.

Conclusion

This case highlights that unexplained fever and inflammatory syndrome in immunocompromised patients warrants specific investigations to identify bacteria such as spirochetes.

Complement Blockade Is a Promising Therapeutic Approach in a Subset of Critically Ill Adult Patients with Complement-Mediated Hemolytic Uremic Syndromes

Thrombotic microangiopathy (TMA) gathers consumptive thrombocytopenia, mechanical haemolytic anemia, and organ damage. Hemolytic uremic syndromes (HUS) are historically classified as primary or secondary to another disease once thrombotic thrombocytopenic purpura (TTP), Shiga-toxin HUS, and cobalamin C-related HUS have been ruled out. Complement genetics studies reinforced the link between complement dysregulation and primary HUS, contributing to reclassifying some pregnancy- and/or post-partum-associated HUS and to revealing complement involvement in severe and/or refractory hypertensive emergencies. By contrast, no firm evidence allows a plausible association to be drawn between complement dysregulation and Shiga-toxin HUS or other secondary HUS. Nevertheless, rare complement gene variants are prevalent in healthy individuals, thus providing an indication that an investigation into complement dysregulation should be carefully balanced and that the results should be cautiously interpreted with the help of a trained geneticist. Several authors have suggested reclassifying HUS in two entities, regardless of they are complement-mediated or not, since the use of eculizumab, an anti-C5 antibody, dramatically lowers the proportion of patients who die or suffer from end-stage renal disease within the year following diagnosis. Safety and the ideal timing of eculizumab discontinuation is currently under investigation, and the long-term consequences of HUS should be closely monitored over time once patients exit emergency departments.

[Gynecologic vasculitis revealing a giant cell arteritis: A case report and literature review]

INTRODUCTION

Genital vasculitis are uncommon. They may be localized or be a manifestation of a systemic vasculitis. We report a patient with a giant cell arteritis (GCA) involving uterine arteries and a literature review on genital vasculitis.

CASE REPORT

A 65-year-old woman was referred to a gynecologist for a cervical intraepithelial neoplasia (CIN) associated with an ovarian mass. An unexpected diagnosis of GCA involving small to medium sized uterine arteries was made through the anatomopathological analysis while the patient was asymptomatic. Two weeks later, she presented typical cranial symptoms of giant cell arteritis (GCA). PET-scanner confirmed the diagnosis of GCA with an involvement of the ascending aorta, and the axillary and the subclavian arteries.

CONCLUSION

Gynecologic vasculitis are rare and usually an asymptomatic manifestations of GCA.

Further characterization of clinical and laboratory features occurring in VEXAS syndrome in a large-scale analysis of multicenter case-series of 116 French patients

BACKGROUND

A new autoinflammatory syndrome related to somatic mutations of UBA1 was recently described and called VEXAS syndrome.

OBJECTIVE

To describe clinical characteristics, laboratory findings and outcomes of VEXAS syndrome.

DESIGN

Case-series.

SETTING

Patients referred to a French multicenter registry between November 2020 and May 2021.

PATIENTS

116 patients with VEXAS syndrome.

MEASUREMENTS

Frequency and median of parameters and vital status, from diagnosis to the end of the follow-up.

RESULTS

Main clinical features were skin lesions (83.5%), non-infectious fever (63.6%), weight loss (62%), lung involvement (49.6%), ocular symptoms (38.8%), relapsing chondritis (36.4%), venous thrombosis (34.7%), lymph nodes (33.9%), and arthralgia (27.3%). Hematological disease was present in 58 cases (50%), considered as myelodysplastic syndrome (MDS, n= 58) and monoclonal gammapathy of unknown significance (n=12).UBA1 mutations included p.M41T (44.8%), p.M41V (30.2%), p.M41L (18.1%), and splice mutations (6.9%). After a median follow-up of 3.0 years, 18 patients died (15.5%), from infectious origin (n=9) and MDS progression (n=3). Unsupervised analysis identified 3 clusters: cluster 1 (47%) with mild-to-moderate disease; cluster 2 (16%) with underlying MDS and higher mortality rates; cluster 3 (37%) with constitutional manifestations, higher C-reactive protein levels and less frequent chondritis. Five-year probability of survival was 84.2% in cluster 1, 50.5 % in cluster 2, and 89.6% in cluster 3. UBA1 p.Met41Leu mutation was associated with a better prognosis.

CONCLUSION

VEXAS syndrome displays a large spectrum of organ manifestations and shows different clinical and prognostic profiles. It also raises a potential impact of the identified UBA1 mutation.

Selectins impair regulatory T cell function and contribute to systemic lupus erythematosus pathogenesis

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by a loss of tolerance toward self-nucleic acids, autoantibody production, interferon expression and signaling, and a defect in the regulatory T (T_reg) cell compartment. In this work, we identified that platelets from patients with active SLE preferentially interacted with T_reg cells via the P-selectin/P-selectin glycoprotein ligand-1 (PSGL-1) axis. Selectin interaction with PSGL-1 blocked the regulatory and suppressive properties of T_reg cells and particularly follicular T_reg cells by triggering Syk phosphorylation and an increase in intracytosolic calcium. Mechanistically, P-selectin engagement on T_reg cells induced a down-regulation of the transforming growth factor-β axis, altering the phenotype of T_reg cells and limiting their immunosuppressive responses. In patients with SLE, we found an up-regulation of P- and E-selectin both on microparticles and in their soluble forms that correlated with disease activity. Last, blocking P-selectin in a mouse model of SLE improved cardinal features of the disease, such as anti-dsDNA antibody concentrations and kidney pathology. Overall, our results identify a P-selectin-dependent pathway that is active in patients with SLE and validate it as a potential therapeutic avenue.

Systemic lupus erythematosus and systemic sclerosis: All roads lead to platelets

Systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) are two phenotypically distincts inflammatory systemic diseases. However, SLE and SSc share pathogenic features such as interferon signature, loss of tolerance against self-nuclear antigens and increased tissue damage such as fibrosis. Recently, platelets have emerged as a major actor in immunity including auto-immune diseases. Both SLE and SSc are characterized by strong platelet system activation, which is likely to be both the witness and culprit in their pathogenesis. Platelet activation pathways are multiple and sometimes redundant. They include immune complexes, Toll-like receptors activation, antiphospholipid antibodies and ischemia-reperfusion associated with Raynaud phenomenon. Once activated, platelet promote immune dysregulation by priming interferon production by immune cells, providing CD40L supporting B lymphocyte functions and providing a source of autoantigens. Platelets are actively implicated in SLE and SSc end-organ damage such as cardiovascular and renal disease and in the promotion of tissue fibrosis. Finally, after understanding the main pathogenic implications of platelet activation in both diseases, we discuss potential therapeutics targeting platelets.

Hydroxychloroquine for the prevention of fetal growth restriction and prematurity in lupus pregnancy: A systematic review and meta-analysis

OBJECTIVES

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that primarily affects women of childbearing age. While the impact of hydroxychloroquine (HCQ) on SLE activity and neonatal lupus occurrence has been evaluated in several studies, its role on prematurity and intrauterine growth restriction (IUGR) remains uncertain. The aim of this study was to assess the impact of HCQ exposure on prematurity and IUGR during pregnancy in women with SLE.

METHODS

We conducted a systematic review and a meta-analysis comparing prematurity and IUGR in SLE pregnancies exposed or not exposed to HCQ. The odds ratio of IUGR and prematurity were calculated and compared between pregnancies in each group according HCQ treatment.

RESULTS

Six studies were included (3 descriptive cohort studies and 3 case series) totalling 870 pregnancies. Of the SLE pregnancies, 308 were exposed to HCQ and were compared to 562 not exposed to HCQ. There was no statistical difference for prematurity or IUGR between groups.

CONCLUSION

This meta-analysis failed to prove the efficacy of HCQ in the prevention of prematurity as well as IUGR during SLE pregnancies. Due to the heterogeneity of the studies, these results should be interpreted cautiously.

[Usefulness of thiopurine methyltransferase polymorphism study and metabolites measurement for patients treated by azathioprine]

Azathioprine is widely used in internal medicine and frequently implicated in occurrence of adverse events. Among these adverse events the bone marrow suppression, a dose-related one, is the most serious because of is potential morbidity and mortality. Severe myelosuppression, associated with abnormal AZA metabolism, is linked to the thiopurine methyltransferase (TPMT) genetic polymorphism that results in a high variability of its activity with 89% of patients with a normal activity, 11% with an intermediate activity, and 0.3% with very low activity leading to a very high risk of bonne marrow suppression. TPMT status can be assessed prior to AZA treatment by measuring enzyme activity or genotyping techniques to identify patients for which the standard dose is not advisable. Furthermore, azathioprine metabolites monitoring is helpful for the follow up of patients, especially in therapeutic failure, to distinguish non-compliant patients from under-dosed, "shunters" or resistant patients.