Interactions between eosinophils and IL-5Rα-positive mast cells in nonadvanced systemic mastocytosis.

BACKGROUND: Bidirectional interactions between eosinophils and mast cells (MCs) have been reported in various allergic diseases. Bone marrow (BM) eosinophilia, and to a lesser extent blood eosinophilia, is common in systemic mastocytosis (SM), but its significance remains unknown. OBJECTIVE: We described blood and BM eosinophil characteristics in SM. METHODS: A large collection of BM biopsy samples was analyzed using immunohistochemical staining and whole-slide imaging. Eosinophil and extracellular granules were detected by eosinophil peroxidase (EPX) staining and MCs by KIT staining. Complementary analyses were conducted using flow cytometry and immunofluorescence. RESULTS: Eosinophil infiltrates and large areas of eosinophil degranulation were observed within or around BM MC infiltrates in SM. EPX staining surface, highlighting intact eosinophils and eosinophil degranulation, was higher in nonadvanced SM (n = 37 BM biopsy samples) compared with both controls (n = 8, P = .0003) and advanced SM (n = 24, P = .014). In nonadvanced SM, positive correlations were observed between serum tryptase levels and percentages of eosinophil counts in BM aspirations (Spearman r coefficient r = 0.38, P = .038), eosinophils count in BM biopsy samples (r = 0.45, P = .007), EPX staining (r = 0.37, P = .035), and eosinophil degranulation (r = 0.39, P = .023). Eosinophil counts in BM biopsy samples also correlated with MC counts (r = 0.47, P = .006) and KIT staining surface (r = 0.49, P = .003). BM MCs expressed IL-5 receptor and other usual eosinophil cytokine/chemokine receptors, and blood eosinophils displayed several increased surface markers compared with controls, suggesting an activated state. CONCLUSION: Our data suggest possible cross talk between MCs and eosinophils, supporting MC tryptase release and MC activation-related symptoms. This suggests a rationale for targeting eosinophils in nonadvanced SM not fully controlled by other therapies.

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.

Acquired haemophilia A in paediatric patients: A retrospective French cohort of eight cases.

Acquired haemophilia A (AHA) is a rare haemorrhagic disease characterised by new-onset haemorrhagic symptoms associated with a dramatic decrease in factor VIII levels and an anti-factor VIII neutralising autoantibody concentration >0.6 Bethesda units. Elderly people are often affected, whereas children are rarely affected; the paediatric incidence reported in the literature is about 0.045 case/million/year. For some time, the paediatric standard of care has been that for adults, but clinicians have often reported poor outcomes. Here, we describe the largest retrospective paediatric AHA cohort assembled to date, including eight patients diagnosed in France from 2000 to 2020.

Characteristics and outcomes associated with CD2 and CD25 expression on bone marrow mast cells in patients with systemic mastocytosis.

Not available.

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.

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.

Comparison of prognostic scores according to WHO classification in 170 patients with advanced mastocytosis and C-finding treated with midostaurin.

Advanced systemic mastocytosis (AdvSM) encompasses heterogeneous mastocytosis subtypes and is associated with poor outcomes. Although midostaurin was the first tyrosine kinase inhibitor to be approved for AdvSM patients, long-lasting responses are limited. The mutation-Adjusted Risk Score (MARS), the International Prognostic Scoring System for mastocytosis (IPSM) and the Global Prognostic Score for Systemic Mastocytosis (GPSM) have been established to characterize the outcomes of patients with overall AdvSM. However, given the outcome's dependency on the AdvSM subtype, prognostic characterization within each subtype is critical. We aimed to study the predictive ability using Harrell's concordance index of prognostic scores according to the AdvSM subtype. We conducted a nationwide retrospective study using the French mastocytosis reference center's registry and included all midostaurin-treated patients with C finding. Overall, 170 patients were identified: 46 aggressive SM (ASM), 11 mast cell leukemia (MCL), and 113 SM with associated hematological neoplasm (SM-AHN). All risk scores improved their discriminative value for overall survival (OS) when combined with the AdvSM subtype. The best predictive value was for adjusted MARS (C-index = 0.689), followed by GPSM (C-index = 0.677) and IPSM (C-index = 0.618). In a multivariable analysis, MARS stratification and the AdvSM subtype were both prognostic for OS. Accordingly, five subgroups of patients with AdvSM and a different median OS were identified: 9.9 months for MCL, 24 months for intermediate/high-risk SM-AHN, 33 months for intermediate/high-risk ASM, 58 months for low-risk SM-AHN and was not reached for low-risk ASM (p < 0.001). The AdvSM subtype and the MARS are the most predictive of OS and should prompt specific management.

Inflammatory disorders associated with trisomy 8-myelodysplastic syndromes: French retrospective case-control study.

OBJECTIVE: We report cases of myelodysplastic syndrome/myeloproliferative neoplasms (MDS/MPN) with trisomy 8 associated with inflammatory and autoimmune diseases (IADs). METHOD: Data for 21 patients with trisomy 8-MDS/MPN and IADs were analyzed and compared to 103 patients with trisomy 8-MDS/MPN without IADs. RESULTS: The median age of MDS/MPN patients with IADs was 67 [59-80]. The IADs were Behçet's-like disease in 11 (52%) patients, inflammatory arthritis in 4 (19%) and Sjögren's syndrome, autoimmune hemolytic anemia, aseptic abscess, periarteritis nodosa, Sweet's syndrome and unclassified vasculitis in one patient each. Overall, 17/21 (81%) patients with IADs received treatment (88% with steroids), with complete and partial response in 7/17 (35%) and 8/17 (47%), respectively. The effect of MDS treatment on IADs could be assessed in seven patients receiving azacytidine: five achieved remission and two partial response. As compared with the 103 trisomy 8-MDS/MPN cases without IADs, those with IADs were more often non-European (P = 0.005) and had poor karyotype (P < 0.001). We found no difference in overall survival or acute myeloid leukemia progression between trisomy 8-associated MDS/MPN with and without IADs. CONCLUSION: The spectrum of IADs associated with trisomy 8-positive MDS/MPN is dominated by Behçet's-like disease. Steroid therapy is effective, but mostly sparing therapies are necessary. Azacytidine could be an effective alternative.

Efficacy and safety of TPO receptor agonists in treatment of ITP associated with predominantly antibody deficiencies.

Predominantly antibody deficiencies have an estimated prevalence of more than 1/25,000. Their classical phenotype entails the association of autoimmune manifestations with increased susceptibility to infections. Up to 8% of these patients ultimately develop immune thrombocytopenic purpura (ITP). Reducing the risk of infections and considering non immunosuppressive treatments, such as thrombopoietin receptor agonists (TPO-RAs), are important needs in these patients. This nationwide retrospective case series assessed outcomes and safety of TPO-RAs as treatment for ITP in adults diagnosed with predominantly antibody deficiencies. Response and complete response to treatment were defined as platelet count reaching 30 x 109/L and 100 x 109/L respectively. We analyzed data from 28 patients. The median follow-up after introduction of the first TPO-RAs was 33 months (range, 2 weeks - 10,6 years). After 6 weeks of follow up, response was achieved for 24 out of 28 patients (85.7%), among which 21 patients (75%) displayed a complete response. At the last available follow-up visit only 7 patients (25%) needed second-line therapies for ITP among which only 5 patients (17.9%) received immunosuppressants. Only 3 patients (10.7%) reported hepatobiliary laboratory adverse events of light or mild severity and 3 patients (10.7%) reported thrombotic events. In conclusion, TPO-RAs appeared as an effective and safe option of treatment in these case series. Our results suggest that Eltrombopag or Romiplostim should be considered as second line therapy of ITP related to predominantly antibody deficiencies.

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.

Acute Airway Obstruction and Cardiopulmonary Arrest due to Tracheomalacia Caused by Megaesophagus Compression Secondary to Achalasia.

We report the case of an 80-year-old woman who presented one episode of cardiopulmonary arrest and two episodes of acute airway obstruction. We found in this patient the presence of tracheomalacia caused by megaesophagus compression secondary to achalasia probably responsible for episodes of acute airway obstruction and cardiopulmonary arrest.

Gastrointestinal Behcet's-like disease with myelodysplastic neoplasms with trisomy 8: a French case series and literature review.

We report the 11 cases of +8-MDS/MPN associated with Behcet's-like syndrome and compare them with Behcet's disease and Crohn's disease, pool with literature cases for analysis. Data for patients with +8-MDS/MPN and Behçet's-like syndrome were collected from MINHEMON. Eleven patients had Behcet's-like syndrome and +8-MDS/MPN (median age 75 years [IQR 65-87]; M/F ratio 0.8). MDS and Behcet's-like syndrome were diagnosed at the same time (7/11, 64%). By comparison with 63 patients with idiopathic Behcet's disease without associated MDS, those with Behcet's-like syndrome and +8-MDS/MPN were older (median 75 vs 48 years; p = .0003) and had less pseudofolliculitis (11% vs 62%; p = .0045) and ocular impairment (0% vs 52%; p = .0008), but more frequent gastrointestinal involvement (60% vs 13%; p = .0005). By comparison with Crohn's disease, 39 patients with Behcet's-like syndrome and +8-MDS/MPN were significantly older (median 72 [53-78] vs 36 [27-45] years; p = .0002) and more frequently had oral aphtosis (97% vs 5%, p < .0001), skin features (50% vs 10%, p = .0005) and arthralgia (63% vs 20%, p = .03). Median survival did not differ between patients with Behcet's-like syndrome and +8-MDS/MPN and those with +8-MDS/MPN (n = 103) (47 vs 34 months, p = .61). AML-free survival did not differ between patients with MDS/MPN with and without Behcet's-like syndrome (p = .29). MDS/MPN with trisomy 8 can be associated with particular phenotype of ulcerative digestive disease resembling Behcet's or Crohn's disease and should be considered a single disease.

Th17 and CD24hiCD27+ regulatory B lymphocytes are biomarkers of response to biologics in rheumatoid arthritis.

BACKGROUND: The aim was to describe the regulatory B and T cells (Breg and Treg) and T helper 17 (Th17) lymphocytes before and under treatment with biologic drugs, and to assess their potential predictive value as biomarkers of response in rheumatoid arthritis (RA). METHODS: This was a non-randomised, single-centre, prospective study. Patients with active RA (American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) 2010) who required the initiation or switch to any biologic drug except rituximab were included. The main judgement criterion was the frequency and absolute number of CD24hiCD27+ Breg and CD24hiCD38hi T2/Breg cells, CD25hiCD127low Treg and CD45RA-CD161+CCR6+ Th17 cells measured at inclusion in both patients and controls, and after 1, 3 and 6 months of treatment (M1, M3 and M6) in patients with RA, and compared with the M6 response to treatment (EULAR response and Disease Activity Score in 28 joints (DAS28) remission). RESULTS: Thirty-one patients with RA and 17 controls were included. There was a reduction in T2/Breg frequency at M0 in patients (p < 0.001) and absolute numbers (p = 0.014) and in immunopositive vs. immunonegative RA (p = 0.016). DAS28 remission at M6 was associated with increased frequency of Treg (p = 0.01). A higher level of CD24hiCD27+ Breg at baseline was associated with DAS28 remission at M6 (p = 0.04) and a good EULAR response at M6 for abatacept-treated patients (p = 0.01). A lower M0 level of Th17 was associated with a good EULAR response at M6 (p = 0.007), notably under anti-cytokine drugs (p = 0.048). CONCLUSIONS: Altogether, these data, although preliminary, suggest that phenotyping of T and B cells has potential value for the stratification of biologic drugs, notably with respect to choosing between abatacept and anti-cytokine blockade.

Clinical spectrum and therapeutic management of systemic lupus erythematosus-associated macrophage activation syndrome: A study of 103 episodes in 89 adult patients.

OBJECTIVES: Macrophage activation syndrome (MAS) is a life-threatening hyperinflammatory syndrome that can occur during systemic lupus erythematosus (SLE). Data on MAS in adult SLE patients are very limited. The aim of this study is to describe the clinical characteristics, laboratory findings, treatments, and outcomes of a large series of SLE-associated MAS. METHODS: We conducted a retrospective study that included 103 episodes of MAS in 89 adult patients with SLE. RESULTS: 103 episodes in 89 adult patients were analyzed. Median age at first MAS episode was 32 (18-80) years. MAS was inaugural in 41 patients (46%).Thirteen patients relapsed. Patients had the following features: fever (100% episodes), increased serum levels of AST (94.7%), LDH (92.3%), CRP (84.5%), ferritin (96%), procalcitonin (41/49 cases). Complications included myocarditis (n=22), acute lung injury (n=15) and seizures (n=11). In 33 episodes, patients required hospitalization in an ICU and 5 died. Thrombocytopenia and high CRP levels were associated independently with an increased risk for ICU admission. High dose steroids alone as first line therapy induced remission in 37/57 cases (65%). Additional medications as first or second line therapies included IV immunoglobulins (n=22), cyclophosphamide (n=23), etoposide (n=11), rituximab (n=3). Etoposide and cyclophosphamide-based regimens had the best efficacy. CONCLUSION: MAS is a severe complication and is often inaugural. High fever and high levels of AST, LDH, CRP, ferritin and PCT should be considered as red flags for early diagnosis. High dose steroids lead to remission in two third of cases. Cyclophosphamide or etoposide should be considered for uncontrolled/severe forms.