Impact of SARS-CoV-2 vaccination and monoclonal antibodies on outcome post-CD19-directed CAR T-cell therapy: an EPICOVIDEHA survey.

Patients with previous CD19-directed chimeric antigen receptor (CAR) T-cell therapy have a prolonged vulnerability to viral infections. Coronavirus disease 2019 (COVID-19) has a great impact and has previously been shown to cause high mortality in this population. Until now, real-world data on the impact of vaccination and treatment on patients with COVID-19 after CD19-directed CAR T-cell therapy are lacking. Therefore, this multicenter, retrospective study was conducted with data from the EPICOVIDEHA survey. Sixty-four patients were identified. The overall mortality caused by COVID-19 was 31%. Patients infected with the Omicron variant had a significantly lower risk of death due to COVID-19 compared with patients infected with previous variants (7% vs 58% [P = .012]). Twenty-six patients were vaccinated at the time of the COVID-19 diagnosis. Two vaccinations showed a marked but unsignificant reduction in the risk of COVID-19-caused mortality (33.3% vs 14.2% [P = .379]). In addition, the course of the disease appears milder with less frequent intensive care unit admissions (39% vs 14% [P = .054]) and a shorter duration of hospitalization (7 vs 27.5 days [P = .022]). Of the available treatment options, only monoclonal antibodies seemed to be effective at reducing mortality from 32% to 0% (P = .036). We conclude that survival rates of CAR T-cell recipients with COVID-19 improved over time and that the combination of prior vaccination and monoclonal antibody treatment significantly reduces their risk of death. This trial was registered at www.clinicaltrials.gov as #NCT04733729.

Refined diagnostic criteria for bone marrow mastocytosis: a proposal of the European competence network on mastocytosis.

In the current classification of the World Health Organization (WHO), bone marrow mastocytosis (BMM) is a provisional variant of indolent systemic mastocytosis (ISM) defined by bone marrow involvement and absence of skin lesions. However, no additional diagnostic criteria for BMM have been proposed. Within the registry dataset of the European Competence Network on Mastocytosis, we compared characteristics and outcomes of 390 patients with BMM and 1175 patients with typical ISM. BMM patients were significantly older, predominantly male, had lower tryptase and lower burden of neoplastic mast cells, and displayed a higher frequency of allergic reactions, mainly triggered by Hymenoptera, than patients with typical ISM. The estimated 10-year progression-free survival of BMM and typical ISM was 95.9% and 92.6%, respectively. In BMM patients defined by WHO-based criteria, the presence of one B-Finding and tryptase level ≥125 ng/mL were identified as risk factors for progression in multivariate analyses. BMM patients without any of these risk factors were found to have better progression-free survival (p < 0.05) and better overall survival (p < 0.05) than other ISM patients. These data support the proposal to define BMM as a separate SM variant characterized by SM criteria, absence of skin lesions, absence of B-Findings, and tryptase levels <125 ng/mL.

Clinical Impact of Skin Lesions in Mastocytosis: A Multicenter Study of the European Competence Network on Mastocytosis.

Mastocytosis is a rare neoplasm characterized by the expansion and accumulation of mast cells in various organ systems. Systemic mastocytosis (SM) may or may not present with cutaneous lesions. To examine the frequency and clinical impact of cutaneous involvement, data on 1,510 patients with mastocytosis collected in the registry of the European Competence Network on Mastocytosis were analyzed. Cutaneous involvement was found in 1,195 of 1,510 patients (79.1%). Of these, 286 had cutaneous mastocytosis, and 721 had SM with skin involvement. Adult patients with skin involvement who did not have a bone marrow examination (n = 188) were defined as having mastocytosis in the skin. In 315 patients, SM without skin involvement was found. The percentage of cases with cutaneous involvement was higher in indolent SM (100%) and smoldering SM (87.9%) compared to aggressive SM (46.8%) or mast cell leukemia (38.5%). After a median follow-up of 5.6 years, no patient with cutaneous mastocytosis had died, but 2.6% of the patients with mastocytosis in the skin, 5.7% of the patients with SM with skin involvement, and 28.95% of the patients with SM without skin involvement had died. Overall survival was longer in patients with skin involvement (cutaneous mastocytosis and/or mastocytosis in the skin and/or SM with skin involvement) than in patients with SM without skin involvement (P < 0.0001). These data argue for a thorough examination of both the skin and bone marrow in adult patients with mastocytosis.

Cytogenetic and molecular aberrations and worse outcome for male patients in systemic mastocytosis.

In systemic mastocytosis (SM), the clinical features and survival vary greatly. Patient-related factors determining the outcome in SM are largely unknown. Methods: We examined the impact of sex on the clinical features, progression-free survival (PFS), and overall survival (OS) in 3403 patients with mastocytosis collected in the registry of the European Competence Network on Mastocytosis (ECNM). The impact of cytogenetic and molecular genetic aberrations on sex differences was analyzed in a subset of patients. Results: Of all patients enrolled, 55.3% were females. However, a male predominance was found in a subset of advanced SM (AdvSM) patients, namely SM with an associated hematologic neoplasm (SM-AHN, 70%; p < 0.001). Correspondingly, organomegaly (male: 23% vs. female: 13%, p = 0.007) was more, whereas skin involvement (male: 71% vs. female: 86%, p = 0.001) was less frequent in males. In all patients together, OS (p < 0.0001) was significantly inferior in males, and also within the WHO sub-categories indolent SM, aggressive SM (ASM) and SM-AHN. PFS was significantly (p = 0.0002) worse in males when all patients were grouped together; due to low numbers of events, this significance persisted only in the subcategory smoldering SM. Finally, prognostically relevant cytogenetic abnormalities (10% vs. 5%, p = 0.006) or molecular aberrations (SRSF2/ASXL1/RUNX1 profile; 63% vs. 40%, p = 0.003) were more frequently present in males. Conclusions: Male sex has a major impact on clinical features, disease progression, and survival in mastocytosis. Male patients have an inferior survival, which seems related to the fact that they more frequently develop a multi-mutated AdvSM associated with a high-risk molecular background.

Patients with mast cell activation symptoms and elevated baseline serum tryptase level have unique bone marrow morphology.

BACKGROUND: Patients with mast cell (MC) activation symptoms and elevated baseline serum tryptase level (MCAS-T) may not necessarily have a clonal MC disorder. Many are diagnosed with hereditary α-tryptasemia (HαT), a genetic trait characterized by autosomal dominant inheritance of multiple copies of TPSAB1 encoding α-tryptase and increased risk for severe anaphylaxis. OBJECTIVE: The aim of our study was to identify and characterize bone marrow MC histopathologic features specific for MCAS-T. METHODS: A total of 43 patients with MCAS-T underwent evaluation, including bone marrow biopsy, for a MC disorder. The results of the work-up for clonal MC disorders such as systemic mastocytosis and monoclonal MC activation syndrome were negative. Bone marrow MC histopathology was reviewed to identify characteristic features of MCAS-T. A subgroup of patients was available for tryptase genotyping. RESULTS: Patients with MCAS-T showed unique morphologic and histologic features when compared with controls. MCs were larger (P < .01), hypogranular (P < .01), frequently detected in paratrabecular (P < .05) and perivascular (P < .01) locations, and associated with bone marrow eosinophilia (P < .01). A total of 10 patients who were available for tryptase genotyping were all confirmed to have HαT. This subgroup was representative of the larger MCAS-T cohort. CONCLUSION: We report unique bone marrow MC phenotypic and histopathologic changes in patients with MCAS-T. These morphologic changes are associated with an elevated tryptase level that has been confirmed to be caused by HαT in all patients available for testing.

Clinical features and survival of patients with indolent systemic mastocytosis defined by the updated WHO classification.

BACKGROUND: In indolent systemic mastocytosis (ISM), several risk factors of disease progression have been identified. Previous studies, performed with limited patient numbers, have also shown that the clinical course in ISM is stable and comparable to that of cutaneous mastocytosis (CM). The aim of this project was to compare the prognosis of patients with ISM with that of patients with CM. METHODS: We employed a dataset of 1993 patients from the registry of the European Competence Network on Mastocytosis (ECNM) to compare outcomes of ISM and CM. RESULTS: We found that overall survival (OS) is worse in ISM compared to CM. Moreover, in patients with typical ISM, bone marrow mastocytosis (BMM), and smoldering SM (SSM), 4.1% of disease progressions have been observed (4.9% of progressions in typical ISM group, 1.7% in BMM, and 9.4% in SSM). Progressions to advanced SM were observed in 2.9% of these patients. In contrast, six patients with CM (1.7%) converted to ISM and no definitive progression to advanced SM was found. No significant differences in OS and event-free survival (EFS) were found when comparing ISM, BMM, and SSM. Higher risk of both progression and death was significantly associated with male gender, worse performance status, and organomegaly. CONCLUSION: Our data confirm the clinical impact of the WHO classification that separates ISM from CM and from other SM variants.

Prognostic impact of eosinophils in mastocytosis: analysis of 2350 patients collected in the ECNM Registry.

Systemic mastocytosis (SM) is frequently associated with eosinophilia. To examine its prevalence and clinical impact in all WHO classification-based subcategories, we analyzed eosinophil counts in 2350 mastocytosis patients using the dataset of the European Competence Network on Mastocytosis. Ninety percent of patients had normal eosinophil counts, 6.8% mild eosinophilia (0.5-1.5 × 109/l), and 3.1% hypereosinophilia (HE; >1.5 × 109/l). Eosinophilia/HE were mainly present in patients with advanced SM (17%/19%), and only rarely recorded in patients with indolent and smoldering SM (5%/1%), and some patients with cutaneous mastocytosis. The eosinophil count correlated with organomegaly, dysmyelopoiesis, and the WHO classification, but not with mediator-related symptoms or allergy. Eosinophilia at diagnosis had a strong prognostic impact (p < 0.0001) on overall survival (OS) and progression-free survival (PFS), with a 10-year OS of 19% for patients with HE, 70% for those with mild eosinophilia, and 88% for patients with normal eosinophil counts. In 89% of patients with follow-up data (n = 1430, censored at start of cytoreductive therapy), eosinophils remained stable. In those with changing eosinophil counts (increase/decrease or mixed pattern), OS and PFS were inferior compared with patients with stable eosinophil counts. In conclusion, eosinophilia and HE are more prevalent in advanced SM and are predictors of a worse outcome.

International prognostic scoring system for mastocytosis (IPSM): a retrospective cohort study.

BACKGROUND: The WHO classification separates mastocytosis into distinct variants, but prognostication remains a clinical challenge. The aim of this study was to improve prognostication for patients with mastocytosis. METHODS: We analysed data of the registry of the European Competence Network on Mastocytosis including 1639 patients (age 17-90 years) diagnosed with mastocytosis according to WHO criteria between Jan 12, 1978, and March 16, 2017. Univariate and multivariate analyses with Cox regression were applied to identify prognostic variables predicting survival outcomes and to establish a prognostic score. We validated this International Prognostic Scoring System in Mastocytosis (IPSM) with data of 462 patients (age 17-79 years) from the Spanish network Red Española de Mastocitosis diagnosed between Jan 22, 1998, and Nov 2, 2017. FINDINGS: The prognostic value of the WHO classification was confirmed in our study (p<0·0001). For patients with non-advanced mastocytosis (n=1380), we identified age 60 years or older (HR 10·75, 95% CI 5·68-20·32) and a concentration of alkaline phosphatase 100 U/L or higher (2·91, 1·60-5·30) as additional independent prognostic variables for overall survival. The resulting scoring system divided patients with non-advanced mastocytosis into three groups: low (no risk factors), intermediate 1 (one risk factor), and intermediate 2 (two risk factors). Overall survival and progression-free survival differed significantly among these groups (p<0·0001). In patients with advanced mastocytosis (n=259), age 60 years or older (HR 2·14, 95% CI 1·42-3·22), a concentration of tryptase 125 ng/mL or higher (1·81, 1·20-2·75), a leukocyte count of 16 × 109 per L or higher (1·88, 1·27-2·79), haemoglobin of 11 g/dL or lower (1·71, 1·13-2·57), a platelet count of 100 × 109 per L or lower (1·63, 1·13-2·34), and skin involvement (0·46, 0·30-0·69) were prognostic variables. Based on these variables, a separate score for advanced mastocytosis with four risk categories was established, with significantly different outcomes for overall survival and progression-free survival (p<0·0001). The prognostic value of both scores was confirmed in 413 patients with non-advanced disease and 49 with advanced mastocytosis from the validation cohort. INTERPRETATION: The IPSM scores for patients with non-advanced and advanced mastocytosis can be used to predict survival outcomes and guide treatment decisions. However, the predictive value of the IPSM needs to be confirmed in forthcoming trials. FUNDING: Austrian Science Fund, Deutsche Forschungsgemeinschaft, Koeln Fortune Program, Charles and Ann Johnson Foundation, Instituto de Salud Carlos III, Fondos FEDER, Research-Foundation Flanders/Fonds Wetenschappelijk Onderzoek, Clinical Research-Fund of the University Hospitals Leuven, and Research-Foundation Flanders/Fonds Wetenschappelijk Onderzoek.

The Data Registry of the European Competence Network on Mastocytosis (ECNM): Set Up, Projects, and Perspectives.

Mastocytosis is a unique hematologic neoplasm with complex biology and pathology and a variable clinical course. The disease can essentially be divided into cutaneous mastocytosis (CM) and systemic mastocytosis (SM). In adults, SM is diagnosed in most cases and manifests as either indolent or advanced disease. Patients with advanced SM have an unfavorable prognosis with reduced survival. However, so far, little is known about the prevalence of various categories of SM and about prognostic factors. In an attempt to learn more about the behavior and evolution of various forms of CM and SM, the European Competence Network on Mastocytosis (ECNM) initiated a mastocytosis registry in 2012. In this article, the set up and start phase of this registry are described. Until 2018, more than 3000 patients from 12 countries and 25 centers have been enrolled. In a majority of all patients, robust follow-up data and relevant clinical end points are available. Using this data set, a series of registry projects have been launched, with the aim to validate previously identified diagnostic and prognostic variables and to identify new disease-related and patient-related parameters in various forms of mastocytosis. Moreover, the core data set of the registry will be useful to establish multiparametric scoring systems through which prognostication and individualized management of patients with mastocytosis should improve in the foreseeable future.

Fatal Anaphylaxis to Yellow Jacket Stings in Mastocytosis: Options for Identification and Treatment of At-Risk Patients.

BACKGROUND: Patients with indolent systemic mastocytosis (ISM) are at risk for severe anaphylactic reactions to yellow jacket (YJ) stings while demonstration of sensitization can be challenging because specific IgE (sIgE) levels are regularly below 0.35 kUA/L. The implication of missing YJ allergy is illustrated by a case of fatal anaphylaxis. OBJECTIVE: To explore the natural course of YJ venom allergy and the diagnostic accuracy and therapeutic consequence of YJ venom sIgE in patients with ISM. METHODS: All patients with ISM seen from 1981 to 2015 (n = 243) were evaluated on the number of YJ stings, reaction severity, and sensitivity and specificity of YJ venom sIgE. YJ venom allergic patients without mastocytosis served as control (n = 313). RESULTS: A total of 153 patients with ISM were stung during adult life. The first systemic reaction was more often severe in patients with ISM than in patients without mastocytosis (69.9% vs 22.0%) and reactions recurred in 40 of 41 re-stung patients with ISM. ISM reactors showed lower YJ venom sIgE levels than nonmastocytosis reactors (0.61 vs 4.83 kUA/L; P < .001) and asymptomatic sensitization was exceedingly rare. In ISM the current clinical threshold of 0.35 kUA/L yields a sensitivity and specificity of 77.6% and 87.5%, respectively. The optimal diagnostic accuracy is achieved at 0.17 kUA/L (sensitivity, 83.6%; specificity, 85.0%). CONCLUSIONS: The high rate of severe reactions and the fatal case underscore the importance of adequate diagnostic sensitivity of sIgE in patients with ISM. The sensitivity of sIgE can be ameliorated by lowering the threshold to 0.17 kUA/L, retaining good specificity. We recommend sIgE screening in all patients with ISM and discussing immunotherapy when YJ venom sIgE exceeds 0.17 kUA/L.

CD30 in systemic mastocytosis.

CD30 is a transmembrane receptor, normally not expressed by mast cells, which regulates proliferation/apoptosis and antibody responses. Aberrant expression of CD30 by mastocytosis mast cells and interaction with its ligand CD30L (CD153) appears to play an important role in the pathogenesis and clinical presentation of systemic mastocytosis. This article highlights the expression profile and role of CD30 and CD30L in physiologic and pathologic conditions, the applicability of CD30 as a marker for systemic mastocytosis, the consequences of mast cell-expressed CD30, and the possibility of future anti-CD30 based cytoreductive therapies.

Higher mast cell load decreases the risk of Hymenoptera venom-induced anaphylaxis in patients with mastocytosis.

BACKGROUND: Increased basal serum tryptase (bsT) levels are a well-described risk factor for Hymenoptera venom-induced anaphylaxis (HVAn) in patients allergic to Hymenoptera venom. Increased bsT levels might also indicate the presence of mastocytosis. In this study we evaluated whether the risk of HVAn increases with increasing mast cell load in patients with mastocytosis. METHODS: Consecutive patients with different subtypes of mastocytosis (n = 329) admitted to the University Medical Center Groningen were retrospectively assessed. As markers for mast cell load, levels of both bsT and the urinary histamine metabolites methylhistamine and methylimidazole acetic acid (MIMA) were used. RESULTS: In the entire patient group, irrespective of disease subtype and Hymenoptera venom exposure, HVAn prevalence gradually increased with increasing marker levels to a maximum of 36% to 47% at a bsT level of 28.0 µg/L, a methylhistamine level of 231.0 µmol/mol creatinine, and a MIMA level of 2.7 mmol/mol creatinine but decreased thereafter with a further increase in these levels. In patients with indolent systemic mastocytosis with a history of Hymenoptera venom exposure after age 15 years or greater (n = 152), MIMA and age at the most recent Hymenoptera sting were independent predictors for HVAn (odds ratios of 0.723 [P = .001] and 1.062 [P < .001], respectively). CONCLUSIONS: In patients with mastocytosis, HVAn prevalence does not increase constantly with increasing levels of mast cell load parameters: after a gradual increase to a maximum of near 50%, it decreases with a further increase in these levels. In the indolent systemic mastocytosis population, all mast cell load markers were independent negative predictors of HVAn. These findings suggest a complex pathophysiologic association between mast cell load and HVAn risk in patients with mastocytosis.