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.

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.

Clinical and Prognostic Factors in Patients with IgG4-Related Kidney Disease.

BACKGROUND: IgG4-related kidney disease is a major manifestation of IgG4-related disease, a systemic fibroinflammatory disorder. However, the clinical and prognostic kidney-related factors in patients with IgG4-related kidney disease are insufficiently defined. METHODS: We conducted an observational cohort study using data from 35 sites in two European countries. Clinical, biologic, imaging, and histopathologic data; treatment modalities; and outcomes were collected from medical records. Logistic regression was performed to identify the possible factors related to an eGFR ≤30 ml/min per 1.73 m 2 at the last follow-up. Cox proportional hazards model was performed to assess the factors associated with the risk of relapse. RESULTS: We studied 101 adult patients with IgG4-related disease with a median follow-up of 24 (11-58) months. Of these, 87 (86%) patients were male, and the median age was 68 (57-76) years. Eighty-three (82%) patients had IgG4-related kidney disease confirmed by kidney biopsy, with all biopsies showing tubulointerstitial involvement and 16 showing glomerular lesions. Ninety (89%) patients were treated with corticosteroids, and 18 (18%) patients received rituximab as first-line therapy. At the last follow-up, the eGFR was below 30 ml/min per 1.73 m 2 in 32% of patients; 34 (34%) patients experienced a relapse, while 12 (13%) patients had died. By Cox survival analysis, the number of organs involved (hazard ratio [HR], 1.26; 95% confidence interval [CI], 1.01 to 1.55) and low C3 and C4 concentrations (HR, 2.31; 95% CI, 1.10 to 4.85) were independently associated with a higher risk of relapse, whereas first-line therapy with rituximab was protective (HR, 0.22; 95% CI, 0.06 to 0.78). At their last follow-up, 19 (19%) patients had an eGFR ≤30 ml/min per 1.73 m 2 . Age (odd ratio [OR], 1.11; 95% CI, 1.03 to 1.20), peak serum creatinine (OR, 2.74; 95% CI, 1.71 to 5.47), and serum IgG4 level ≥5 g/L (OR, 4.46; 95% CI, 1.23 to 19.40) were independently predictive for severe CKD. CONCLUSIONS: IgG4-related kidney disease predominantly affected middle-aged men and manifested as tubulointerstitial nephritis with potential glomerular involvement. Complement consumption and the number of organs involved were associated with a higher relapse rate, whereas first-line therapy with rituximab was associated with lower relapse rate. Patients with high serum IgG4 concentrations (≥5 g/L) had more severe kidney disease.

Combining thrombopoietin receptor agonists with immunosuppressive drugs in adult patients with multirefractory immune thrombocytopenia, an update on the French experience.

Combining drugs could be an effective option for treating multirefractory ITP, that is, patients not responding to rituximab, thrombopoietin receptor agonists (TPO-RA) and splenectomy. We conducted a retrospective, multicenter, observational study including multirefractory ITP patients who received a combination of a TPO-RA and an immunosuppressive drug. We included 39 patients (67% women, median age 59 years [range 21-96]), with a median ITP duration of 57 months [3-393] and a median platelet count at initiation of 10 × 109 /L [1-35]. The combination regimen was given for a median duration of 12 months [1-103] and included eltrombopag (51%) or romiplostim (49%), associated with mycophenolate mofetil (54%), azathioprine (36%), cyclophosphamide (5%), cyclosporin (3%) or everolimus (3%). Overall, 30 patients (77%) achieved at least a response (platelet count ≥30 × 109 /L and at least doubling baseline during at least 3 months), including 24 complete responses (platelet count >100 × 109 /L during at least 3 months) with a median time to response of 30 days [7-270] and a median duration of response of 15 months [4-63]. Severe adverse event related to ITP treatment was observed in 31%. In conclusion, this study confirms that some patients with multirefractory ITP can achieve long lasting response with this combination.

Prolonged response after TPO-RA discontinuation in primary ITP: results of a prospective multicenter study.

Sustained response off treatment (SROT) after thrombopoietin receptor agonist (TPO-RA) discontinuation has been reported in immune thrombocytopenia (ITP). This prospective multicenter interventional study enrolled adults with persistent or chronic primary ITP and complete response (CR) on TPO-RAs. The primary end point was the proportion of patients achieving SROT (platelet count >30 × 109/L and no bleeding) at week 24 (W24) with no other ITP-specific medications. Secondary end points included the proportion of sustained CR off-treatment (SCROT, platelet count >100 × 109/L and no bleeding) and SROT at W52, bleeding events, and pattern of response to a new course of TPO-RAs. We included 48 patients with a median age of 58.5 years; 30 of 48 had chronic ITP at TPO-RA initiation. In the intention-to-treat analysis, 27 of 48 achieved SROT, 15 of 48 achieved SCROT at W24; 25 of 48 achieved SROT, and 14 of 48 achieved SCROT at W52. No severe bleeding episode occurred in patients who relapsed. Among patients rechallenged with TPO-RA, 11 of 12 achieved CR. We found no significant clinical predictors of SROT at W24. Single-cell RNA sequencing revealed enrichment of a tumor necrosis factor α signaling via NF-κB signature in CD8+ T cells of patients with no sustained response after TPO-RA discontinuation, which was further confirmed by a significant overexpression of CD69 on CD8+ T cells at baseline in these patients as compared with those achieving SCROT/SROT. Our results strongly support a strategy based on progressive tapering and discontinuation of TPO-RAs for patients with chronic ITP who achieved a stable CR on treatment. This trial was registered at www.clinicaltrials.gov as #NCT03119974.

Rituximab vs Cyclophosphamide Induction Therapy for Patients With Granulomatosis With Polyangiitis.

Importance: Results of randomized clinical trials have demonstrated rituximab's noninferiority to cyclophosphamide as induction therapy for antineutrophil cytoplasm antibody (ANCA)-associated vasculitides (AAV), with neither treatment having a specific advantage for granulomatosis with polyangiitis (GPA). However, post hoc analysis results have suggested that rituximab might be more effective than cyclophosphamide in inducing remission in patients with proteinase 3-positive AAV. Objective: To compare the effectiveness of rituximab and cyclophosphamide in inducing GPA remission in a large population of unselected patients. Design, Setting, and Participants: This comparative effectiveness study used multicenter target trial emulation observational data from 32 French hospitals in the French Vasculitis Study Group Registry. Groups were determined according to treatments received, without any intervention from the investigators. Inverse probability of treatment weighting was used to correct for baseline imbalance between groups. Participants included patients with newly diagnosed or relapsing GPA who satisfied American College of Rheumatology classification criteria and/or Chapel Hill Consensus Conference nomenclature. Data were analyzed from October 1, 2021, to May 31, 2022. Exposures: At least 1 infusion of rituximab or cyclophosphamide for induction therapy between April 1, 2008, and April 1, 2018. Main Outcomes and Measures: The primary outcome was remission rate at month 6 (±2 months), with remission defined as a Birmingham Vasculitis Activity Score (BVAS) of 0 and prednisone dose of 10 mg/d or less. The BVAS is a validated tool for small-vessel vasculitis and used to assess the level of disease activity, with a numerical weight attached to each involved organ system. The BVAS has a range of 0 to 63 points; a score of 0 indicates no disease activity. Subgroup analyses included the primary outcome for patients with a new diagnosis, for most recently treated patients, and for patients with myeloperoxidase-ANCA positivity. Results: Among 194 patients with GPA included in the analysis (mean [SD] age, 54 [15] years; 110 men [56.7%]), 165 (85.1%) had a new diagnosis, and 147 of 182 with data available (80.8%) had proteinase 3-ANCA positivity. Sixty-one patients received rituximab and 133 received cyclophosphamide for induction therapy. In the weighted analysis, the primary outcome was reached for 73.1% of patients receiving rituximab vs 40.1% receiving cyclophosphamide (relative risk [RR], 1.82 [95% CI, 1.22-2.73]; risk difference, 33.0% [95% CI, 12.2%-53.8%]; E value for RR, 3.05). Similar results were observed in the subgroup of patients with newly diagnosed GPA and those with a more recent treatment. In the subset of 27 patients with myeloperoxidase-ANCA-positive GPA, 8 of 10 rituximab recipients and 8 of 17 cyclophosphamide recipients met the primary end point (unweighted RR, 1.73 [95% CI, 0.96-3.11]). Conclusions and Relevance: In this comparativeness effectiveness study using clinical data, rituximab induction therapy for GPA was more frequently associated with remission than cyclophosphamide. These results inform clinical decision-making concerning the choice of remission induction therapy for this subset of patients with AAV.

Antiphospholipid syndrome in patients over 65 years: A comparative study of clinical and biological features and thrombotic relapses.

OBJECTIVE: The aim of the study was to describe clinical and biological characteristics and thrombotic relapses of patients diagnosed with antiphospholipid syndrome (APS) after the age of 65 years, in comparison with patients diagnosed with APS before 65. METHODS: This retrospective multicenter study was performed to 2005 from 2017 and included patients diagnosed with APS after the age of 65 years, in accordance with Sydney criteria. We compared these patients with APS patients diagnosed before the age of 65 years, and with control thrombotic patients older than 65 years. RESULTS: Fifty-eight APS patients over the age of 65 years were compared to 127 APS patients aged less than 65 and to 58 controls. In elderly APS versus younger APS, there was a male predominance (58.6% vs 36.2% p = .001); myocardial infarction and lower limb deep vein thrombosis (LLDVT) were more frequent in elderly, respectively, 12.1% versus 1.6% (p = .005), and 44.8% versus 29.9% (p = .048). Anticardiolipin antibody (aCL) IgM was more frequently found in old patients compared to younger patients (33.9% vs 18.1%, p = .02), contrary to lupus anticoagulant (LAC) (52.8% vs 66.9%, p = .02). Older patients were more often diagnosed with single positive APS (82.8% vs 59.8% p = .002). The thrombotic relapse free survival was lower in elderly APS patients (p = .044) compared to younger APS. Elderly APS patients had more recurrent arterial and venous thrombosis (p = .03) and had poorer overall survival (p = .004) than elderly controls. CONCLUSION: In this study, APS was different in patients aged more than 65 years, with a male predominance and more myocardial infarctions and LLDVT at diagnosis. Single antiphopholipid positivity and aCL IgM were more frequent in older patients. Older patient with APS had more thrombotic recurrence during follow-up. Compared to elderly controls, elderly APS patients had more thrombosis recurrences and poorer survival.

Immune-mediated thrombotic thrombocytopenic purpura prognosis is affected by blood pressure.

Background: The prevalence, prognostic role, and diagnostic value of blood pressure in immune-mediated thrombotic thrombocytopenic purpura (iTTP) and other thrombotic microangiopathies (TMAs) remain unclear. Methods: Using a national cohort of iTTP (n = 368), Shigatoxin-induced hemolytic uremic syndrome (n = 86), atypical hemolytic uremic syndrome (n = 84), and hypertension-related thrombotic microangiopathy (n = 25), we sought to compare the cohort's blood pressure profile to assess its impact on prognosis and diagnostic performances. Results: Patients with iTTP had lower blood pressure than patients with other TMAs, systolic (130 [interquartile range (IQR) 118-143] vs 161 [IQR 142-180] mmHg) and diastolic (76 [IQR 69-83] vs 92 [IQR 79-105] mmHg, both p < 0.001). The best threshold for iTTP diagnosis corresponded to a systolic blood pressure <150 mmHg. iTTP patients presenting with hypertension had a significantly poorer survival (hazard ratio 1.80, 95% confidence interval 1.07-3.04), and this effect remained significant after multivariable adjustment (hazard ratio = 1.14, 95% confidence interval 1.00-1.30). Addition of a blood pressure criterion modestly improved the French clinical score to predict a severe A disintegrin and metalloprotease with thrombospondin type 1 deficiency in patients with an intermediate score (i.e., either platelet count <30 × 109/L or serum creatinine <200 µM). Conclusions: Elevated blood pressure at admission affects the prognosis of iTTP patients and may help discriminate them from other TMA patients. Particular attention should be paid to blood pressure and its management in these patients.

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.

Comparative study of granulomatosis with polyangiitis subsets according to ANCA status: data from the French Vasculitis Study Group Registry.

OBJECTIVE: To investigate whether antineutrophil cytoplasm antibody (ANCA)-negative and myeloperoxidase (MPO)-ANCA-positive granulomatosis with polyangiitis (GPA) differ from proteinase-3 (PR3)-ANCA-positive GPA. METHODS: Diagnostic characteristics and outcomes of newly diagnosed French Vasculitis Study Group Registry patients with ANCA-negative, MPO-ANCA-positive or PR3-ANCA-positive GPA satisfying American College of Rheumatology criteria and/or Chapel Hill Conference Consensus Nomenclature were compared. RESULTS: Among 727 GPA, 62 (8.5%) were ANCA-negative, 119 (16.4%) MPO-ANCA-positive and 546 (75.1%) PR3-ANCA-positive. ANCA-negative patients had significantly (p<0.05) more limited disease (17.7% vs 5.8%) and less kidney involvement (35.5% vs 58.9%) than those PR3-ANCA-positive or MPO-ANCA-positive, with comparable relapse-free (RFS) and overall survival (OS). MPO-ANCA-positive versus PR3-ANCA-positive and ANCA-negative patients were significantly more often female (52.9% vs 42.1%), older (59.8 vs 51.9 years), with more frequent kidney involvement (65.5% vs 55.2%) and less arthralgias (34.5% vs 55.1%), purpura (8.4% vs 17.1%) or eye involvement (18.5% vs 28.4%); RFS was similar but OS was lower before age adjustment. PR3-positive patients' RFS was significantly lower than for ANCA-negative and MPO-positive groups combined, with OS higher before age adjustment. PR3-ANCA-positivity independently predicted relapse for all GPA forms combined but not when comparing only PR3-ANCA-positive versus MPO-ANCA-positive patients. CONCLUSIONS: Based on this large cohort, ANCA-negative versus ANCA-positive patients more frequently had limited disease but similar RFS and OS. MPO-ANCA-positive patients had similar RFS but lower OS due to their older age. PR3-ANCA-positive GPA patients' RFS was lower than those of the two other subsets combined but that difference did not persist when comparing only PR3 versus MPO-ANCA-positive patients.

Effective Anti-SARS-CoV-2 Immune Response in Patients With Clonal Mast Cell Disorders.

BACKGROUND: Mast cells are key players in innate immunity and the TH2 adaptive immune response. The latter counterbalances the TH1 response, which is critical for antiviral immunity. Clonal mast cell activation disorders (cMCADs, such as mastocytosis and clonal mast cell activation syndrome) are characterized by abnormal mast cell accumulation and/or activation. No data on the antiviral immune response in patients with MCADs have been published. OBJECTIVE: To study a comprehensive range of outcomes in patients with cMCAD with PCR- or serologically confirmed coronavirus disease 2019 and to characterize the specific anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immune response in this setting. METHODS: Clinical follow-up and outcome data were collected prospectively over a 12-month period by members of the French Centre de Référence des Mastocytoses rare disease network. Anti-SARS-CoV-2-specific T-cell activity was measured with an ELISA, and humoral responses were evaluated by assaying circulating levels of specific IgG, IgA, and neutralizing antibodies. RESULTS: Overall, 32 patients with cMCAD were evaluated. None required noninvasive or mechanical ventilation. Two patients were admitted to hospital for oxygen and steroid therapy. The SARS-CoV-2-specific immune response was characterized in 21 of the 32 patients. Most had high counts of circulating SARS-CoV-2-specific, IFN-γ-producing T cells and high titers of neutralizing antispike IgGs. The patients frequently showed spontaneous T-cell IFN-γ production in the absence of stimulation; this production was correlated with basal circulating tryptase levels (a marker of the mast cell burden). CONCLUSIONS: Patients with cMCADs might not be at risk of severe coronavirus disease 2019, perhaps due to their spontaneous production of IFN-γ.

Patients of 75 years and over with ANCA-associated vasculitis have a lower relapse risk than younger patients: A multicentre cohort study.

BACKGROUND: Little is known about antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) in older patients. We aim to study relapse risk of granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA) in patients diagnosed after 75 years and compare it with those of patients aged 65-75 years. METHODS: Data from AAV patients aged ≥65 years were extracted from the French Vasculitis Study Group (FVSG) database and from a call for observation to FVSG members. Cox and Fine-Gray models were used to assess relapse risk, taking death into account either as a censoring or a competing event, respectively. RESULTS: The analysis included 219 patients aged ≥75 years (median 79) and 80 patients aged 65-75 years (median 70), of those 155 had GPA (52%), 136 MPA (45%), with 95 (32%) anti-proteinase 3 positivity and 179 (61%) anti-myeloperoxidase. Patients aged ≥75 years had a lower relapse risk in multivariate analysis (cause-specific hazards ratio [CSHR] 0.54, 95% CI [0.33-0.89], p = 0.016, Cox model; subdistribution hazard ratio [SHR] 0.46, 95% CI [0.29-0.74], p = 0.001, Fine-Gray model) after taking into account vasculitis type. Patients aged ≥75 years had a lower probability of being treated for remission maintenance with a combination of glucocorticoids and immunosuppressants (vs. glucocorticoids alone, HR 0.28, 95% CI [0.11-0.68], p = 0.005) after adjusting to Five Factor Score, although relapse-free survival was significantly longer when receiving such combination (CSHR 0.40, 95% [CI 0.24-0.67], p < 0.001). CONCLUSIONS: AAV patients ≥75 years have a lower relapse risk than patients aged 65-75 years despite a lower probability of having received maintenance therapy with a combination of glucocorticoids and immunosuppressants, but they still benefit from such treatment regimen.

Significance of eosinophilia in granulomatosis with polyangiitis: data from the French Vasculitis Study Group Registry.

OBJECTIVE: To describe disease presentation and long-term outcome of granulomatosis with polyangiitis (GPA) patients according to blood eosinophils count (Eos) at vasculitis diagnosis. METHODS: Data from newly diagnosed GPA patients registered in the French Vasculitis Study Group database with available eosinophil count at diagnosis were reviewed. Disease characteristics, rate and type of relapses, and overall survival were analysed according to Eos, categorized as normal (<500/mm3), mild-to-moderate hypereosinophilia (HE) (between 500 and 1500/mm3) and severe HE (>1500/mm3). RESULTS: Three hundred and fifty-four patients were included. At diagnosis, 90 (25.4%) patients had HE ≥500/mm3; they were more likely male (73% vs 56%, P = 0.006) and had more frequent cutaneous manifestations (49% vs 33%, P = 0.01), peripheral neuropathy (32% vs 17%, P = 0.004) and higher BVAS (21 vs 18, P = 0.01), compared with those with Eos <500/mm3. Patients with severe HE (n = 28; median Eos 2355, range 1500-9114) had more frequent renal function worsening at presentation (P = 0.008). After a median follow-up of 3.95 (interquartile range 1.95-6.76) years, no difference was found in overall relapse rates according to baseline Eos, but those with HE experienced more neurological (P = 0.013) and skin (P = 0.024) relapses and had more frequently peripheral neuropathy as damage at last follow-up (P = 0.02). Overall survival was not significantly different in patients with normal Eos or HE at diagnosis. (P = 0.08). CONCLUSIONS: Blood HE at diagnosis, observed in about one-quarter of GPA patients, identifies a subgroup of patients with a more severe disease and higher rate of skin and neurological involvement both at presentation and during follow-up.

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.

Catastrophic adult-onset Still's disease as a distinct life-threatening clinical subset: case-control study with dimension reduction analysis.

OBJECTIVES: Adult-onset Still's disease (AOSD) is a rare systemic inflammatory disorder. Diagnosing AOSD can be challenging, as disease presentation and clinical course are highly heterogeneous. For unclear reasons, a few patients develop life-threatening complications. Our objective was to determine whether these cases resulted from therapeutic delay or could represent a peculiar AOSD subset. METHODS: We conducted a multicentre retrospective study of 20 AOSD patients with organ failure requiring intensive care unit admission and 41 control AOSD patients without organ failure. Clinico-biological data at hospital admission were explored using supervised analyses and unsupervised dimension reduction analysis (factor analysis of mixed data, FAMD). RESULTS: Disease duration before admission was shorter in patients with life-threatening AOSD (median, 10 vs 20 days, p = 0.007). Disease duration before AOSD therapy initiation also tended to be shorter (median, 24 vs 32 days, p = 0.068). Despite this shorter disease duration, FAMD, hierarchical clustering and univariate analyses showed that these patients exhibited distinctive characteristics at first presentation, including younger age; higher frequency of splenomegaly, liver, cardiac and/or lung involvement; less frequent arthralgia; and higher ferritin level. In multivariate analysis, 3 parameters predicted life-threatening complications: lack of arthralgia, younger age and shorter time between fever onset and hospitalisation. CONCLUSION: This study suggests that life-threatening complications of AOSD occur very early, in a peculiar subset, which we propose to name catastrophic adult-onset Still's disease (CAOSD). Its exact burden may be underestimated and remains to be clarified through large multicentre cohorts. Further studies are needed to identify red flags and define the optimal therapeutic strategy.

Platelet features allow to differentiate immune thrombocytopenia from inherited thrombocytopenia.

Immune thrombocytopenia (ITP) is an acquired bleeding disorder, for which no specific diagnostic test exists. Inherited thrombocytopenia (IT) can mimic ITP and lead to unappropriated management with significant morbidity. Here, in small cohorts of these two disorders, we explored whether platelet sialylation and platelet activation could allow to discriminate the two conditions. We also aimed to confirm the value of immature platelet counts in this discrimination. Platelet sialylation and the expression level of P-selectin were assessed by multiparameter flow cytometry. Immature platelets were estimated on a Sysmex XN 9000 analyzer. No significant difference in platelet sialylation was observed between ITP and IT. Contrarily, platelet activation was significantly higher in ITP patients (p = 0.008). The immature platelet fraction, as previously demonstrated, was significantly lower in the ITP group compared to the IT group (p = 0.014). That statistical significance was achieved in this small pilot study suggests that the two easily available assays of immature platelet count and P-selectin expression could help physicians to reach the proper diagnosis in complex cases of thrombocytopenia.

Risk factors for symptomatic vascular events in giant cell arteritis: a study of 254 patients with large-vessel imaging at diagnosis.

AIMS: To identify factors associated with vascular events in patients with giant cell arteritis (GCA). METHODS: We performed a retrospective study of GCA patients diagnosed over a 20-year-period, who all underwent vascular imaging evaluation at diagnosis. Symptomatic vascular events were defined as the occurrence of any aortic event (aortic dissection or symptomatic aortic aneurysm), stroke, myocardial infarction, limb or mesenteric ischemia and de novo lower limbs arteritis stage 3 or 4. Patients with symptomatic vascular event (VE+) and without were compared, and risk factors were identified in a multivariable analysis. RESULTS: Thirty-nine (15.4%) of the 254 included patients experienced at least one symptomatic vascular event during follow-up, with a median time of 21.5 months. Arterial hypertension, diabetes, lower limbs arteritis or vascular complication at diagnosis were more frequent in VE+ patients (p < 0.05), as an abnormal computed tomography (CT)-scan at diagnosis (p = 0.04), aortitis (p = 0.01), particularly of the descending thoracic aorta (p = 0.03) and atheroma (p = 0.03). Deaths were more frequent in the VE+ group (37.1 versus 10.3%, p = 0.0003). In multivariable analysis, aortic surgery [hazard ratio (HR): 10.46 (1.41-77.80), p = 0.02], stroke [HR: 22.32 (3.69-135.05), p < 0.001], upper limb ischemia [HR: 20.27 (2.05-200.12), p = 0.01], lower limb ischemia [HR: 76.57 (2.89-2027.69), p = 0.009], aortic atheroma [HR: 3.06 (1.06-8.82), p = 0.04] and aortitis of the descending thoracic aorta on CT-scan at diagnosis [HR: 4.64 (1.56-13.75), p = 0.006] were independent predictive factors of a vascular event. CONCLUSION: In this study on GCA cases with large vessels imaging at diagnosis, aortic surgery, stroke, upper or lower limb ischemia, aortic atheroma and aortitis of the descending thoracic aorta on CT-scan, at GCA diagnosis, were independent predictive factors of a vascular event. PLAIN LANGUAGE SUMMARY: Risk factors for symptomatic vascular events in giant cell arteritisThis study was performed to identify the risk factors for developing symptomatic vascular event during giant cell arteritis (GCA) because these are poorly known.We performed a retrospective study of GCA patients diagnosed over a 20-year-period, who all underwent vascular imaging evaluation at diagnosis.Patients with symptomatic vascular event (VE+) and without (VE-) were compared, and risk factors were identified in a multivariable analysis.Thirty-nine patients experienced at least one symptomatic vascular event during follow-up, with a median time of 21.5 months.Arterial hypertension, diabetes, lower limbs arteritis or vascular complication at diagnosis were significantly more frequent in VE+ patients, as an abnormal CT-scan at diagnosis, aortitis, particularly of the descending thoracic aorta and atheroma. Deaths were more frequent in the VE+ group.Among 254 GCA patients, 39 experienced at least one vascular event during follow-up.Aortic surgery, stroke, upper and lower limb ischemia were vascular event risk factors.Aortic atheroma and descending thoracic aorta aortitis on CT-scan were vascular event risk factors.This study on GCA cases with large vessels imaging at diagnosis, showed that aortic surgery, stroke, upper or lower limb ischemia, aortic atheroma and aortitis of the descending thoracic aorta on CT-scan, at GCA diagnosis, were independent predictive factors of a vascular event.

FIP1L1-PDGFRA-Associated Hypereosinophilic Syndrome as a Treatable Cause of Watershed Infarction.

Background and Purpose: Ischemic stroke has been reported in various conditions associated with eosinophilia. FIP1L1-PDGFRA fusion ([Fip1-like 1-platelet-derived growth factor receptor alpha]; F/P) leads to the proliferation of the eosinophilic lineage and thus to a clonal hypereosinophilic syndrome that is highly responsive to imatinib. Methods: We previously reported on a nationwide retrospective study of 151 patients with F/P-associated clonal hypereosinophilic syndrome. Patients from this cohort with a clinical history of ischemic stroke (as well as 2 additional cases) were further analyzed to better define their clinical picture and outcomes. Results: Sixteen male patients (median age, 51 [43­59] years) with low-to-intermediate cardiovascular risk were included. Median National Institutes of Health Stroke Scale was 4 (range, 1­6). Most cerebral imaging disclosed multiple bilateral infarctions of watershed distribution (69%). Despite frequent cardiac involvement (50%), cardiac thrombus was evidenced in a single patient and, according to the TOAST classification (Trial of ORG 10172 in Acute Stroke Treatment), 62.5% of strokes were presumably of undetermined etiology. Among the 15 patients treated with imatinib, and after a median follow-up of 4.5 years, stroke recurred in only 3 patients (consisting of either cardio embolic or hemorrhagic events, unrelated to the first episode). Conclusions: F/P+ clonal hypereosinophilic syndrome is a diagnosis to consider in patients with unexplained ischemic stroke and hypereosinophilia (especially in the setting of multiple cortical borderzone distribution) and warrants prompt initiation of imatinib.