Involvement of the JAK-STAT pathway in the molecular landscape of tyrosine kinase fusion-negative hypereosinophilic syndromes: A nationwide CEREO study.

We investigated using a custom NGS panel of 149 genes the mutational landscape of 64 consecutive adult patients with tyrosine kinase fusion-negative hypereosinophilia (HE)/hypereosinophilic syndrome (HES) harboring features suggestive of myeloid neoplasm. At least one mutation was reported in 50/64 (78%) patients (compared to 8/44 (18%) patients with idiopathic HE/HES/HEUS used as controls; p < .001). Thirty-five patients (54%) had at least one mutation involving the JAK-STAT pathway, including STAT5B (n = 18, among which the hotspot N642H, n = 13), JAK1 (indels in exon 13, n = 5; V658F/L, n = 2), and JAK2 (V617F, n = 6; indels in exon 13, n = 2). Other previously undescribed somatic mutations were also found in JAK2, JAK1, STAT5B, and STAT5A, including three patients who shared the same STAT5A V707fs mutation and features consistent with primary polycythemia. Nearly all JAK-STAT mutations were preceded by (or associated with) myelodysplasia-related gene mutations, especially in RNA-splicing genes or chromatin modifiers. In multivariate analysis, neurologic involvement (hazard ratio [HR] 4.95 [1.87-13.13]; p = .001), anemia (HR 5.50 [2.24-13.49]; p < .001), and the presence of a high-risk mutation (as per the molecular international prognosis scoring system: HR 6.87 [2.39-19.72]; p < .001) were independently associated with impaired overall survival. While corticosteroids were ineffective in all treated JAK-STAT-mutated patients, ruxolitinib showed positive hematological responses including in STAT5A-mutated patients. These findings emphasize the usefulness of NGS for the workup of tyrosine kinase fusion-negative HE/HES patients and support the use of JAK inhibitors in this setting. Updated classifications could consider patients with JAK-STAT mutations and eosinophilia as a new "gene mutated-entity" that could be differentiated from CEL, NOS, and idiopathic HES.

Efficacy and safety of mammalian target of rapamycin inhibitors in systemic mastocytosis: A nationwide French pilot study.

Systemic mastocytosis (SM) corresponds to a rare and heterogeneous spectrum of diseases characterized by the accumulation of atypical mast cells (MCs). Advanced mastocytosis (Adv-SM) is associated with poor survival; in contrast, patients with non-advanced SM (non-Adv-SM) usually have a normal life expectancy but may experience poor quality of life. Despite recent therapeutic progress including tyrosine kinase inhibitors, new treatment options are needed for refractory and/or intolerant patients with both severely symptomatic and Adv-SM. In vitro, the mTOR pathway is activated in MCs from patients bearing the KIT D816V mutation. Furthermore, rapamycin induces the apoptosis of KIT D816V MCs selectively. In this nationwide study, we report the outcomes of patients diagnosed with SM and treated with a mammalian target of rapamycin inhibitor (imTOR) within the French National Reference Center for mastocytosis (CEREMAST). All patients registered were relapsing, treatment-refractory, or ineligible for other cytoreductive therapy. Non-Adv-SM patients received imTOR as a monotherapy (rapamycin/everolimus), and Adv-SM patients received imTOR as a monotherapy or in combination with cytarabine. The objective response rate (ORR) in non-Adv-SM was 60% (partial response in 40% and major response in 20%), including reductions in skin involvement, mediator release symptoms, and serum tryptase. In the Adv-SM group, the ORR was 20% (including one major response and one partial response, both in patients with a KIT D816V mutation), which enabled a successful bridge to allogeneic stem cell transplantation in one patient. Our results suggest that imTOR treatment has potential benefits in patients with SM harboring a KIT D816V mutation.

Histological characterization of liver involvement in systemic mastocytosis.

BACKGROUND AND AIMS: Systemic mastocytosis (SM) is characterized by the accumulation of atypical mast cells (MCs) in organs. Liver histology of SM has been marginally described and accurate histological classification is critical, given the consequences of aggressive SM diagnosis. We aimed to describe the histological features associated with liver SM using updated tools. METHODS: Using the database of the French Reference Centre for Mastocytosis, we retrospectively identified patients with a liver biopsy (LB) and a diagnosis of SM. All LB procedures were performed according to the local physician in charge and centrally reviewed by an expert pathologist. RESULTS: A total of 28 patients were included: 6 had indolent SM, 9 had aggressive SM, and 13 had SM with an associated hematologic neoplasm. Twenty-five (89%) patients presented hepatomegaly, and 19 (68%) had portal hypertension. The LB frequently showed slight sinusoid dilatation (82%). Fibrosis was observed in 3/6 indolent SM and in almost all advanced SM cases (21/22), but none of them showed cirrhosis. A high MC burden (>50 MCs/high-power field) was correlated with elevated blood alkaline phosphatase levels (p = .030). The presence of portal hypertension was associated with a higher mean fibrosis grade (1.6 vs. 0.8 in its absence; p = .026). In advanced SM, the presence of nodular regenerative hyperplasia (NRH) was associated with decreased overall survival (9.5 vs. 46.3 months, p = .002). CONCLUSIONS: MC infiltration induced polymorphic hepatic lesions and the degree of fibrosis is associated with portal hypertension. NRH identifies a poor prognosis subgroup of patients with advanced SM. Assessing liver histology can aid in SM prognostic evaluation.

Susceptibility to mycobacterial infection in VEXAS syndrome.

OBJECTIVES: VEXAS is a recently described acquired auto-inflammatory and hematologic syndrome caused by somatic mutations in UBA1. To date, VEXAS is not a recognized cause of acquired immunodeficiency. PATIENTS AND METHODS: Two of our 10 VEXAS patients developed a disseminated Mycobacterium avium infection. To shed light on this observation, we retrospectively studied all patients with disseminated non-tuberculous mycobacterial infections (NTMi) seen at our institution over 13 years. Inclusion criteria were a positive blood/bone marrow culture, or 2 positive cultures from distinct sites, or one positive culture with 2 involved sites. RESULTS: patient 1 presented with fever, rash, orbital cellulitis and lung infiltrates. Patient 2 presented with fever and purpura. In both cases, Mycobacterium avium was identified on bone marrow culture. Twenty cases of disseminated NTMi were reviewed. Among 11 HIV-negative patients, three had chronic immune-mediated disease; three had untreated myeloid neoplasm; two had VEXAS; one had undergone kidney transplantation; one had GATA-2 deficiency; and one had no identified aetiology. None had lymphoid neoplasia or had undergone bone marrow transplantation. HIV-negative cases had higher CD4 counts than HIV-positive patients (median CD4: 515/mm3  vs 38/mm3, p< 0.001). Monocytopenia was present in seven cases. At 2 years, six patients had died, including both VEXAS patients. DISCUSSION: VEXAS patients have an intrinsic susceptibility to disseminated NTMi, which may result from monocytic dysfunction. NTMi can mimic VEXAS flare. Clinicians should maintain a high suspicion for opportunistic infections before escalating immunosuppressive therapy. Further studies are needed to confirm and better decipher the herein reported observations.

Characteristics and Prognosis Factors of Pneumocystis jirovecii Pneumonia According to Underlying Disease: A Retrospective Multicenter Study.

BACKGROUND: Pneumocystis jirovecii pneumonia (PcP) remains associated with high rates of mortality, and the impact of immunocompromising underlying disease on the clinical presentation, severity, and mortality of PcP has not been adequately evaluated. RESEARCH QUESTION: Does the underlying disease and immunosuppression causing PcP impact the outcome and clinical presentation of the disease? STUDY DESIGN AND METHODS: In this multicenter retrospective observational study, conducted from January 2011 to December 2021, all consecutive patients admitted with a proven or probable diagnosis of PcP according to The European Organisation for Research and Treatment of Cancer consensus definitions were included to assess the epidemiology and impact of underlying immunosuppressive diseases on overall and 90-day mortality. RESULTS: Overall, 481 patients were included in the study; 180 (37.4%) were defined as proven PcP and 301 (62.6%) were defined as probable PcP. Patients with immune-mediated inflammatory diseases (IMIDs) or solid tumors had a statistically poorer prognosis than other patients with PcP at day 90. In multivariate analysis, among the HIV-negative population, solid tumor underlying disease (OR, 5.47; 95% CI, 2.16-14.1; P < .001), IMIDs (OR, 2.19; 95% CI, 1.05-4.60; P = .037), long-term corticosteroid exposure (OR, 2.07; 95% CI, 1.03-4.31; P = .045), cysts in sputum/BAL smears (OR, 1.92; 95% CI, 1.02-3.62; P = .043), and SOFA score at admission (OR, 1.58; 95% CI, 1.39-1.82; P < .001) were independently associated with 90-day mortality. Prior corticotherapy was the only immunosuppressant associated with 90-day mortality (OR, 1.67; 95% CI, 1.03-2.71; P = .035), especially for a prednisone daily dose ≥ 10 mg (OR, 1.80; 95% CI, 1.14-2.85; P = .010). INTERPRETATION: Among patients who were HIV-negative, long-term corticosteroid prior to PcP diagnosis was independently associated with increased 90-day mortality, specifically in patients with IMIDs. These results highlight both the needs for PcP prophylaxis in patients with IMIDs and to early consider PcP curative treatment in severe pneumonia among patients with IMIDs.

Rituximab as maintenance therapy for ANCA-associated vasculitides: pooled analysis and long-term outcome of 277 patients included in the MAINRITSAN trials.

OBJECTIVE: To compare the long-term efficacy and safety of azathioprine (AZA), 18-month fixed-schedule rituximab (RTX), 18-month tailored RTX and 36-month RTX in preventing relapses in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis who achieved a complete remission after induction therapy. Patients treated with 36-month RTX received either a fixed or a tailored regimen for the first 18 months and a fixed regimen for the last 18 months (36-month fixed/fixed RTX and 36-month tailored/fixed RTX, respectively). METHODS: The Maintenance of Remission using Rituximab in Systemic ANCA-associated Vasculitis (MAINRITSAN) trials sequentially compared: 18-month fixed-schedule RTX versus AZA (MAINRITSAN); 18-month fixed-schedule RTX versus 18-month tailored-RTX (MAINRITSAN2); and extended therapy to 36 months with four additional RTX infusions after MAINRITSAN2 versus placebo (MAINRITSAN3). Patients were then followed prospectively through month 84 and their data were pooled to analyse relapses and adverse events. The primary endpoint was relapse-free survival at month 84. RESULTS: 277 patients were enrolled and divided in 5 groups: AZA (n=58), 18-month fixed-schedule RTX (n=97), 18-month tailored-RTX (n=40), 36-month tailored/fixed RTX (n=42), 36-month fixed/fixed RTX (n=41). After adjustment for prognostic factors, 18-month fixed-schedule RTX was superior to AZA in preventing major relapses at month 84 (HR 0.38, 95% CI 0.20 to 0.71). The 18-month tailored-RTX regimen was associated with an increased risk of major relapse compared with fixed-schedule regimen (HR 2.92, 95% CI 1.43 to 5.96). The risk of major relapse was similar between 36-month fixed/fixed and 18-month fixed-RTX (HR 0.69, 95% CI 0.38 to 1.25). CONCLUSIONS: According to these results, it appears that the 84-month remission rate is higher with an 18-month fixed RTX regimen compared with AZA and 18-month tailored RTX. Also, extending RTX to 36 months does not appear to reduce the long-term relapse rate compared with the 18-month fixed RTX regimen. However, as this study was underpowered to make this comparison, further prospective studies are needed to determine the potential long-term benefits of extending treatment in these patients.

Pathophysiologic implications of elevated prevalence of hereditary alpha-tryptasemia in all mastocytosis subtypes.

BACKGROUND: Mastocytosis and monoclonal mast cell (MC) activation syndrome (MMAS) are heterogeneous conditions characterized by the accumulation of atypical MCs. Despite the recurrent involvement of KIT mutations, the pathophysiologic origin of mastocytosis and MMAS is unclear. Although hereditary α-tryptasemia (HαT, related to TPSAB1 gene duplication) is abnormally frequent in these diseases, it is not known whether the association is coincidental or causal. OBJECTIVE: We evaluated the prevalence of HαT in all mastocytosis subtypes and MMAS and assessed the pathophysiologic association with HαT. METHODS: Clinical data, laboratory data, KIT mutations, TPSAB1 duplication (assessed by droplet digital PCR), and HαT prevalence were retrospectively recorded for all patients with mastocytosis and MMAS registered in the French national referral center database and compared to a control cohort. To increase the power of our analysis for advanced systemic mastocytosis (advSM), we pooled our cohort with literature cases. RESULTS: We included 583 patients (27 with MMAS and 556 with mastocytosis). The prevalence of HαT in mastocytosis was 12.6%, significantly higher than in the general population (5.7%, P = .002) and lower than in MMAS (33.3%, P = .02). HαT+ patients were more likely to have anaphylactic reactions and less likely to have cutaneous lesions than HαT- patients (43.0% vs 24.4%, P = .006; 57.7% vs 75.6%, respectively, P = .006). In the pooled analysis, the prevalence of HαT was higher in advSM (11.5%) than in control cohorts (5.2%, P = .01). CONCLUSION: Here we confirm the increase incidence of anaphylaxis in HαT+ mastocytosis patients. The increased prevalence of HαT in all subtypes of systemic mastocytosis (including advSM) is suggestive of pathophysiologic involvement.

Dysregulation of neutrophil oxidant production and interleukin-1-related cytokines in granulomatosis with polyangiitis.

OBJECTIVES: Neutrophils play a key role in ANCA-associated vasculitis, both as targets of autoimmunity and facilitators of vascular damage. In granulomatosis with polyangiitis (GPA), data regarding the production of reactive oxygen species (ROS) in neutrophils are unclear. Further, recent data suggests that ROS production could have an anti-inflammatory effect through the regulation of the inflammasome and IL-1-related cytokines. We aimed to analyse the ROS production in neutrophils from patients with GPA and investigate its association with IL-1-related cytokines and the autoantigen proteinase 3 (PR3). METHODS: Seventy-two GPA patients with disease flare were included in the NEUTROVASC prospective cohort study. ROS production was evaluated in whole blood of patients with active GPA and compared with the same patients in remission or healthy controls. Associations between ROS production, PR3 membrane expression on neutrophils, serum levels of IL-1-related cytokines as well as inflammasome-related proteins were analyzed. RESULTS: We observed a robust defect in ROS production by neutrophils from patients with active GPA compared with healthy controls, independent of glucocorticoid treatment. Serum levels of IL-1-related cytokines were significantly increased in GPA patients, particularly in patients with kidney involvement, and levels of these cytokines returned to normal after patients achieved remission. Further, inflammasome-related proteins were significantly dysregulated in the cytosol of neutrophils as well as the serum from GPA patients. CONCLUSION: Our data suggests that ROS production and regulation of the inflammasome in neutrophils from patients with GPA are disturbed and may be a potential therapeutic target. CLINICAL TRIAL REGISTRATION NUMBER: NCT01862068, clinicaltrials.gov, https://www.clinicaltrials.gov.

Dupilumab for relapsing or refractory sinonasal and/or asthma manifestations in eosinophilic granulomatosis with polyangiitis: a European retrospective study.

BACKGROUND: Eosinophilic granulomatosis with polyangiitis (EGPA) is often associated with glucocorticoid-dependent asthma and/or ear, nose and throat (ENT) manifestations. When immunosuppressants and/or mepolizumab are ineffective, dupilumab could be an option. We describe the safety and efficacy of off-label use of dupilumab in relapsing and/or refractory EGPA. PATIENTS AND METHODS: We conducted an observational multicentre study of EGPA patients treated with dupilumab. Complete response was defined by Birmingham Vasculitis Activity Score (BVAS)=0 and prednisone dose ≤4 mg/day, and partial response by BVAS=0 and prednisone dose >4 mg/day. Eosinophilia was defined as an eosinophil count >500/mm3. RESULTS: Fifty-one patients were included. The primary indication for dupilumab was disabling ENT symptoms in 92%. After a median follow-up of 13.1 months, 18 patients (35%) reported adverse events (AEs), including two serious AEs. Eosinophilia was reported in 34 patients (67%), with a peak of 2195/mm3 (IQR 1268-4501) occurring at 13 weeks (IQR 4-36) and was associated with relapse in 41%. Twenty-one patients (41%) achieved a complete response and 12 (24%) a partial response. Sixteen (31%) patients experienced an EGPA relapse while on dupilumab, which was associated with blood eosinophilia in 14/16 (88%) patients. The median eosinophil count at the start of dupilumab was significantly lower in relapsers than in non-relapsers, as was the median time between stopping anti-IL-5/IL-5R and switching to dupilumab. CONCLUSION: These results suggest that dupilumab may be effective in treating patients with EGPA-related ENT manifestations. However, EGPA flares occurred in one-third of patients and were preceded by eosinophilia in 88%, suggesting that caution is required.

Invasive fungal diseases in patients with autoimmune diseases: a case series from the French RESSIF network.

OBJECTIVES: We aimed to describe patients with autoimmune diseases (AID) developing invasive fungal disease (IFD) and identify factors associated with short-term mortality. METHODS: We analysed cases of IFD associated with AID from the surveillance network of invasive fungal diseases (Réseau de surveillance des infections fongiques invasives, RESSIF) registry of the French national reference centre for invasive mycoses. We studied association of AID-specific treatments with 30-day mortality. We analysed total lymphocyte and CD4-T cell counts in patients with Pneumocystis jirovecii pneumonia (PCP). RESULTS: From 2012 to 2018, 549 individuals with IFD and AID were included, mainly with PCP (n=227, 41.3%), fungemia (n=167, 30.4%) and invasive aspergillosis (n=84, 15.5%). Rheumatoid arthritis (RA) and anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitides (AAV) were the most frequent AID in PCP (n=55 and 25, respectively) and invasive aspergillosis (n=15 and 10, respectively), inflammatory bowel diseases (IBDs) were predominant in fungemia (n=36). At IFD diagnosis, 365 (66.5%) patients received glucocorticoids (GCs), 285 (51.9%) immunosuppressants, 42 (7.7%) tumor necrosis factor (TNF)-α blockers, 75 (13.7%) other biologics. Mortality at 30 days was 28.1% (143/508). Fungemia and high-dose GCs were independently associated with higher 30-day mortality. In PCP patients, lymphopenia <1500/mm3 was frequent (132/179, 73.7%) even if CD4+T cell count exceeded 200/mm3 in 56/78 patients (71.8%) (median 472.5/mm3, IQR 160-858). CONCLUSION: IFD associated with AID occurs primarily in RA, AAV and IBD, especially when treated with GCs and immunosuppressants. Mortality is high, especially for patients on high-dose GCs. Lymphopenia may help identify risk of PCP, but normal CD4+T cell count does not rule out the risk. Further studies are needed to assess the individual risk factors for IFD.

Predictors of acute ischemic cerebral lesions in immune-mediated thrombotic thrombocytopenic purpura and hemolytic uremic syndrome.

BACKGROUND: The immune form of thrombotic thrombocytopenic purpura (iTTP) and the hemolytic and uremic syndrome (HUS) are two major forms of thrombotic microangiopathy (TMA). Their treatment has been recently greatly improved. In this new era, both the prevalence and predictors of cerebral lesions occurring during the acute phase of these severe conditions remain poorly known. AIM: The prevalence and predictors of cerebral lesions appearing during the acute phase of iTTP and Shiga toxin-producing Escherichia coli-HUS or atypical HUS were evaluated in a prospective multicenter study. METHODS: Univariate analysis was performed to report the main differences between patients with iTTP and those with HUS or between patients with acute cerebral lesions and the others. Multivariable logistic regression analysis was used to identify the potential predictors of these lesions. RESULTS: Among 73 TMA cases (mean age 46.9 ± 16 years (range 21-87 years) with iTTP (n = 57) or HUS (n = 16), one-third presented with acute ischemic cerebral lesions on magnetic resonance imagery (MRI); two individuals also had hemorrhagic lesions. One in ten patients had acute ischemic lesions without any neurological symptom. The neurological manifestations did not differ between iTTP and HUS. In multivariable analysis, three factors predicted the occurrence of acute ischemic lesions on cerebral MRI: (1) the presence of old infarcts on cerebral MRI, (2) the level of blood pulse pressure, (3) the diagnosis of iTTP. CONCLUSION: At the acute phase of iTTP or HUS, both symptomatic and covert ischemic lesions are detected in one third of cases on MRI. Diagnosis of iTTP and the presence of old infarcts on MRI are associated with the occurrence of such acute lesions as well as increased blood pulse pressure, that may represent a potential target to further improve the therapeutic management of these conditions.

French guidelines for the etiological workup of eosinophilia and the management of hypereosinophilic syndromes.

Eosinophilic-related clinical manifestations are protean and the underlying conditions underpinning eosinophilia are highly diverse. The etiological workup of unexplained eosinophilia/hypereosinophilia can be challenging, and can lead sometimes to extensive, inappropriate, costly and/or invasive investigations. To date, guidelines for the etiological workup and management of eosinophilia are mainly issued by hematologists, and thus mostly cover the scope of clonal hypereosinophilic syndromes (HES). Here, thanks to an extensive literature review, and thanks to the joint work of a large panel of experts involving physicians from both adult and pediatric medicine and from various subspecialties (as well as a representative of a patients' association representative), we provide recommendations for both the step-by step diagnostic workup of eosinophilia (whether unexplained or within specific contexts) as well as the management and follow-up of the full spectrum of eosinophilic disorders (including clonal, reactive, lymphocytic and idiopathic HES, as well as single-organ diseases). Didactic prescription summaries intended to facilitate the prescription of eosinophil-targeted drugs are also provided, as are practical diagnostic and therapeutic algorithms. Lastly, this set of recommendations also includes a summary intended for general practitioners, as well as an overview of the therapeutic patient education program set up by the French reference center for HES. Further updates will be mandatory as new validated information emerges.

Regulation of CD8 T cell by B-cells: A narrative review.

Activation of CD4 T cells by B cells has been extensively studied, but B cell-regulated priming, proliferation, and survival of CD8 T cells remains controversial. B cells express high levels of MHC class I molecules and can potentially act as antigen-presenting cells (APCs) for CD8 T cells. Several in vivo studies in mice and humans demonstrate the role of B cells as modulators of CD8 T cell function in the context of viral infections, autoimmune diseases, cancer and allograft rejection. In addition, B-cell depletion therapies can lead to impaired CD8 T-cell responses. In this review, we attempt to answer 2 important questions: 1. the role of B cell antigen presentation and cytokine production in the regulation of CD8 T cell survival and cell fate determination, and 2. The role of B cells in the formation and maintenance of CD8 T cell memory.

Disease patterns and specific trajectories of anti-MDA5-related disease: a multicentre retrospective study of 70 adult patients.

Introduction: This study aimed to provide an updated analysis of the different prognostic trajectories of patients with anti-melanoma differentiation-associated gene 5 (MDA5) antibodies. Methods: Among a cohort of 70 patients, baseline characteristics and phenotypes, treatments and outcomes were analyzed. A Cox proportional hazards model was used to identify factors associated with poor outcomes, i.e., death or progressive disease at the last follow-up. Results: Among the 70 patients, 45 were women, and 54 were Caucasian. A dermatologic involvement was observed in 58 (83%) patients, including 40 with MDA5 vasculopathy-related skin lesions. Muscular involvement was observed in 39 (56%) patients. Interstitial lung disease (ILD) was observed at baseline in 52 (74%) patients, including 23 (44%) who developed rapidly progressive (RP) ILD. Seven (10%) patients showed thromboembolic complications within the first weeks of diagnosis, and eight (11%) other patients developed a malignancy (4 before the diagnosis of anti-MDA5 disease). Poor outcomes were observed in 28 (40%) patients, including 13 (19%) deaths. Among the 23 patients with RP-ILD, 19 (79%) showed poor outcomes, including 12 (63%) who died. In multivariate analyses, RP-ILD (hazard ratio (HR), 95% CI: 8.24 [3.21-22], p<0.0001), the occurrence of thromboembolic events (HR: 5.22 [1.61-14.77], p=0.008) and the presence of any malignancy (HR: 19.73 [6.67-60], p<0.0001) were the three factors independently associated with poor outcomes. Discussion: This new independent cohort confirms the presence of different clinical phenotypes of anti-MDA5 diseases at baseline and the poor prognosis associated with RP-ILD. Thromboembolic events and malignancies were also identified as prognostic factors.

Neutrophil-derived extracellular vesicles induce endothelial inflammation and damage through the transfer of miRNAs.

The critical role of neutrophils in pathological inflammation, notably in various autoimmune disorders, is currently the focus of renewed interest. Here, we demonstrate for the first time that activation of neutrophils with various inflammatory stimuli induces the release of extracellular vesicles (EVs) that are internalized by endothelial cells (ECs), thus leading to the transfer of miR-223, miR-142-3p and miR-451 and subsequent endothelial damage. Indeed, while miR-223 has little effect on EC responses, we show that the induced expression of miR-142-3p and miR-451 in ECs results in profound cell damage, especially in inflammatory conditions, characterized by a dramatic increase in cell apoptosis, impaired angiogenic repair responses, and the induction of IL-6, IL-8, CXCL10 and CXCL11 expression. We show that the strong deleterious effect of miR-142-3p may be due in part to its ability to block the activation of ERK1/2 and eNOS-mediated signals in ECs. miR-142-3p also inhibits the expression of RAC1, ROCK2 and CLIC4, three genes that are critical for EC migration and angiogenic responses. Importantly, miR-223, miR-142-3p and miR-451 are markedly increased in kidney biopsies from patients with active ANCA-associated vasculitis, a severe autoimmune disease that is prototypical of a neutrophil-induced microvascular damage. Taken together, our results suggest that miR-142-3p and miR-451 released in EVs by activated neutrophils can target EC to trigger an inflammatory cascade and induce direct vascular damage, and that therapeutic strategies based on the inhibition of these miRNAs in ECs will have implications for neutrophil-mediated inflammatory diseases.

Kidney Histopathology Can Predict Kidney Function in ANCA-Associated Vasculitides with Acute Kidney Injury Treated with Plasma Exchanges.

BACKGROUND: Data from the PEXIVAS trial challenged the role of plasma exchange (PLEX) in ANCA-associated vasculitides (AAV). We aimed to describe kidney biopsy from patients with AAV treated with PLEX, evaluate whether histopathologic findings could predict kidney function, and identify which patients would most benefit from PLEX. METHODS: We performed a multicenter, retrospective study on 188 patients with AAV and AKI treated with PLEX and 237 not treated with PLEX. The primary outcome was mortality or KRT at 12 months (M12). RESULTS: No significant benefit of PLEX for the primary outcome was found. To identify patients benefitting from PLEX, we developed a model predicting the average treatment effect of PLEX for an individual depending on covariables. Using the prediction model, 223 patients had a better predicted outcome with PLEX than without PLEX, and 177 of them had >5% increased predicted probability with PLEX compared with without PLEX of being alive and free from KRT at M12, which defined the PLEX-recommended group. Risk difference for death or KRT at M12 was significantly lower with PLEX in the PLEX-recommended group (-15.9%; 95% CI, -29.4 to -2.5) compared with the PLEX not recommended group (-4.8%; 95% CI, 14.9 to 5.3). Microscopic polyangiitis, MPO-ANCA, higher serum creatinine, crescentic and sclerotic classes, and higher Brix score were more frequent in the PLEX-recommended group. An easy to use score identified patients who would benefit from PLEX. The average treatment effect of PLEX for those with recommended treatment corresponded to an absolute risk reduction for death or KRT at M12 of 24.6%. CONCLUSIONS: PLEX was not associated with a better primary outcome in the whole study population, but we identified a subset of patients who could benefit from PLEX. However, these findings must be validated before utilized in clinical decision making.

Localized versus systemic granulomatosis with polyangiitis: data from the French Vasculitis Study Group Registry.

OBJECTIVE: To describe the main features at diagnosis and evolution over time of patients with localized granulomatosis with polyangiitis (L-GPA) compared with those of systemic GPA (S-GPA). METHODS: EULAR definitions of L-GPA, i.e. upper and/or lower respiratory tract involvement, and S-GPA were applied to patients from the French Vasculitis Study Group Registry. L-GPA and S-GPA patients' characteristics at diagnosis and long-term outcomes were analysed and compared. RESULTS: Among the 795 Registry patients, 79 (10%) had L-GPA. Their main clinical manifestations were rhinitis, lung nodules, sinusitis and otitis. L-GPA vs S-GPA patients at diagnosis, respectively, were younger, more frequently had saddle nose deformity or subglottic stenosis and were less often PR3-ANCA-positive. L-GPA vs S-GPA induction therapy less frequently included CYC but more often a combination of MTX and glucocorticoids; 64% of MTX-treated patients experienced disease progression within 18 months post-diagnosis. L- and S-GPA patients' estimated relapse-free-survival probabilities, relapse rates and refractory disease rates at each time point were comparable, but L-GPA patients had more frequent ENT and lung relapses, and higher overall survival rates (P<0.02). Over a median follow-up of 3.5 years, 18 (22.8%) L-GPA progressed to S-GPA, either as a relapse after a period in remission or more frequently in the context of refractory disease. L-GPA patients experienced more ENT-related damage. CONCLUSIONS: The relapse risks of L-GPA and S-GPA were similar, but relapse patterns differed and L-GPA overall survival rate was higher. About one-quarter of L-GPA patients developed S-GPA over time, but without end-stage organ involvement.

Deleterious neurological impact of diagnostic delay in immune-mediated thrombotic thrombocytopenic purpura.

BACKGROUND: Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a rare life-threatening thrombotic microangiopathy requiring urgent therapeutic plasma exchange (TPE). However, the exact impact of a slight delay in TPE initiation on the subsequent patients' outcome is still controversial. AIM: We aimed to study the frequency, short-term neurological consequences, and determinants of diagnostic delay in iTTP. METHODS: We conducted a retrospective monocentric study including patients with a first acute episode of iTTP (2005-2020) classified into 2 groups: delayed (>24h from first hospital visit, group 1) and immediate diagnosis (≤24h, group 2). RESULTS: Among 42 evaluated patients, 38 were included. Eighteen cases (47%) had a delayed diagnosis (median: 5 days). The main misdiagnosis was immune thrombocytopenia (67%). The mortality rate was 5% (1 death in each group). Neurological events (stroke/TIA, seizure, altered mental status) occurred in 67% vs 30% patients in group 1 and 2, respectively (p = 0.04). Two patients in group 1 exhibited neurological sequelae. The hospital length of stay was longer in group 1 (p = 0.02). At the first hospital evaluation, potential alternative causes of thrombocytopenia were more prevalent in group 1 (33% vs 5%, p = 0.04). Anemia was less frequent in group 1 (67% vs 95%, p = 0.04). All patients had undetectable haptoglobin levels. By contrast, 26% of schistocytes counts were <1%, mostly in group 1 (62% vs 11%, p = 0.01). CONCLUSION: Diagnostic delay is highly prevalent in iTTP, with a significant impact on short-term neurological outcome. In patients with profound thrombocytopenia, the thorough search for signs of incipient organ dysfunction, systematic hemolysis workup, and proper interpretation of schistocytes count are the key elements of early diagnosis of TTP.