Search Results (123)

Indolent systemic mastocytosis (ISM) is an under-recognised cause of secondary osteoporosis, and skeletal fragility may be the only presenting feature, delaying diagnosis. We describe four adults referred to a tertiary endocrinology service for unexplained osteoporosis or low-trauma fractures, in whom systemic mastocytosis (SM) was identified during work-up. All had elevated basal serum tryptase (41.4–87.0 µg/L), bone-marrow biopsy showing atypical mast cells and the KIT D816V variant; cutaneous lesions were absent in every case. Three patients fulfilled WHO 2022 criteria for ISM. The fourth had coexistent JAK2 V617F-positive post-essential-thrombocythaemia myelofibrosis and was classified as SM with associated haematological neoplasm (SM-AHN); his mast cell clone (tryptase 43.7 µg/L; KIT D816V VAF 0.391%) behaved indolently and contributed clinically through osteoporosis alone, illustrating that an indolent mast cell component can be overlooked when a chronic myeloid neoplasm dominates the picture. Presentations ranged from an isolated low-energy L5 fracture in a 55-year-old man, to multiple vertebral compression fractures despite denosumab in a 71-year-old woman with primary hyperparathyroidism, to severe wasp-sting anaphylaxis in a 43-year-old man. After multidisciplinary review, all received intravenous zoledronic acid with vitamin D repletion; KIT-targeted therapy is under consideration in selected patients. Although causal inferences cannot be drawn from four retrospectively identified cases, the series illustrates how ISM may be missed in unexplained or treatment-refractory osteoporosis—particularly in younger men, those with prior severe anaphylaxis, and those fracturing on antiresorptive therapy—and supports combining basal serum tryptase with high-sensitivity peripheral-blood KIT D816V testing, in line with the WHO/ICC/AIM-ECNM 2022–2024 criteria. Prospective studies are needed. Full article

Hymenoptera venom allergy is a cause of anaphylaxis, which significantly affects patients’ daily lives due to the constant fear of accidental stings. Venom immunotherapy (VIT) is the only treatment capable of preventing severe systemic reactions (SSRs). Limited long-term real-life data are available, integrating both clinical and immunological outcomes. A five-year prospective observational study was conducted on 35 patients with a history of SSR who underwent VIT at a tertiary allergy center in Southern Italy; two of them had a diagnosis of systemic mastocytosis. Most patients were sensitized to Vespula, but others to Apis, Polistes dominula and Vespa crabro, reflecting the exposure pattern characteristic of Mediterranean regions. Clinical outcomes following accidental re-stings and serological trends, including total IgE, venom-specific IgE, and baseline serum tryptase, were assessed at treatment initiation and after five years of maintenance therapy. During the entire follow-up, all patients tolerated VIT. No SSRs occurred after accidental stings in 17/35 patients, confirming clinical protection achieved with VIT. Vespula serum-specific IgE presented a highly significant decrease; total IgE, tryptase and specific IgE for Apis, Polistes dominula and Vespa crabro showed a statistically significant decrease. Our findings reinforce the role of VIT as a well-tolerated, effective and disease-modifying treatment in a real-world setting. Full article

Background and Objectives: Systemic mastocytosis (SM) is a clonal mast cell disorder characterized by abnormal mast cell accumulation and activation in multiple organs, leading to mediator-related symptoms, including anaphylaxis. Drug hypersensitivity reactions (DHRs) are a major clinical challenge in SM, but their frequency and characteristics remain undefined. This study aimed to evaluate the frequency of drug allergy, identify high-risk drug groups, investigate reaction characteristics, and examine the relationship between drug reactions, baseline serum tryptase levels, and SM subtypes in patients with SM. Materials and Methods: We retrospectively analyzed 34 patients diagnosed with SM between 2009 and 2024 at Ege University Faculty of Medicine. Clinical features, SM subtypes, baseline serum tryptase levels, and DHR characteristics were recorded. Reactions to antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol, anesthetics, radiocontrast media (RCM), and COVID-19 vaccines were graded using the Ring and Messmer anaphylaxis classification. Results: Among 34 patients, the mean age was 48.6 ± 13.3 years, 53% were male, and 10 (29.4%) had DHRs. The most common culprit drugs were NSAIDs (17.6%) and β-lactam antibiotics (14.7%). Anaphylaxis was the predominant reaction, frequently associated with hypotension. In 5 patients (14.7%), drug-induced anaphylaxis was the initial and only manifestation of SM. No hypersensitivity reactions occurred to quinolones, general anesthetics, or COVID-19 vaccines. Median baseline tryptase was 50.25 µg/L (min–max: 8.59–200.00) overall, and 41.85 µg/L (min–max: 19.00–200.00) among those with DHRs. Conclusions: Patients with SM are at increased risk of severe DHRs, particularly to NSAIDs and beta-lactam antibiotics. In some patients, drug allergy may be the first and only manifestation of SM. Measurement of baseline serum tryptase is essential in patients with drug-induced anaphylaxis. A comprehensive allergy assessment, including tolerance testing and individualized counseling, is crucial to ensure safe pharmacological management. Full article

Background/Objectives: Hereditary alpha-tryptasemia (HαT) is increasingly recognized as a genetic modifier of mast cell-mediated disease severity and has been associated with heightened mediator-related symptoms and an elevated risk of anaphylaxis. This study aimed to describe the clinical characteristics, multisystem manifestations, and treatment responses of eight patients with HαT and concomitant mast cell disorders. Methods: In this single-center retrospective study, eight adults with confirmed TPSAB1 copy number gain and a diagnosis of systemic mastocytosis (SM), cutaneous mastocytosis (CM), or mast cell activation syndrome (MCAS) were evaluated. Baseline assessments included demographics, clinical history, basal serum tryptase (BST), TPSAB1 genotyping, KIT D816V testing, and bone marrow examination when indicated. Symptom burden was quantified at baseline and week 8 using the Mastocytosis Activity Score (MAS). All patients received mediator-targeted therapy; omalizumab was administered in selected high-risk cases. Results: Eight patients (62.5% male, mean age 53.9 ± 12.0 years) carried TPSAB1 duplication. The median BST was 16.2 ng/mL (range, 14.3–51.2). Severe anaphylaxis occurred in 75% of patients, predominantly drug-induced, while Hymenoptera venom triggered the remaining cases. Gastroesophageal reflux (87.5%), cutaneous symptoms (62.5%), neuropsychiatric features (62.5%), and autonomic dysfunction (37.5%) were common. The mean MAS decreased significantly from 27.25 ± 7.40 to 18.25 ± 6.48 after 8 weeks of high-dose antihistamines, with omalizumab providing marked additional benefit in selected patients. Conclusions: In this cohort, patients with HαT and coexisting mast cell disorders exhibited a high burden of mediator-related symptoms and a notable frequency of anaphylaxis. TPSAB1 genotyping may provide additional genetic information that aids in contextualizing clinical heterogeneity and mediator-related symptom burden in patients with mast cell disorders. Incorporation of HαT testing into routine evaluation may optimize individualized management. Full article

Systemic mastocytosis comprises a group of clonal mast cell disorders characterized by multisystem involvement. Bone involvement represents a major source of morbidity, particularly in young men affected by indolent systemic mastocytosis. This review provides an integrated and up-to-date overview of SM-related bone disease. We dissect the dual and context-dependent role of mast cells in bone remodeling, detailing how they promote osteoclastogenesis, suppress osteoblast function, and, in advanced disease, drive osteosclerosis. We critically appraise available treatments, including classic anti-resorptive therapy and emerging anabolic strategies. We further discuss the transformative impact of KIT-directed tyrosine kinase inhibitors, particularly avapritinib, which has demonstrated for the first time the ability to reverse not only osteoporosis but also osteosclerosis. Finally, we explore the emerging role of machine learning models in SM, proposing their application to individualized prediction of osteoporosis and fracture risk in SM. By bridging clinical care, bone biology, and therapeutic advances, this review underscores the need for a paradigm shift in which SM-related bone disease is recognized as a dynamic process requiring early identification, integrated risk stratification, and coordinated use of anti-resorptive, disease-modifying, and data-driven precision approaches to prevent fractures and improve long-term outcomes and quality of life in this delicate category of patients. Full article

Background: Mastocytosis is a rare hematologic disorder, classified into cutaneous mastocytosis (CM) and systemic mastocytosis (SM). Understanding age-related differences in presentation and management is essential for individualized care. Methods: Data from patients recruited from the Montreal Children’s and Montreal General Hospitals between 2015 and 2024 were analyzed. Descriptive statistics were employed to present patient demographics, clinical characteristics, and medication usage. Statistical analyses included Fisher’s exact test for categorical variables and t-tests or non-parametric equivalents for continuous variables. Results: A total of 63 patients were included, comprising 39 children and 24 adults. Children had a median age of 1.9 years, while adults had a median age of 49.3 years. CM was exclusively prevalent in children (100.0%), while SM was more common in adults (45.8%). Adults with SM had a significantly higher median age than CM (49.4 versus 44.7 years, respectively, p = 0.03). Epinephrine use was more frequent in adult SM patients (36.4% versus 0%, respectively, p = 0.03). No pediatric patients required epinephrine for symptom control. Conclusions: This study highlights important clinical differences between pediatric and adult mastocytosis. CM was more common in children while SM predominated in adults and was associated with greater flare severity and higher tryptase levels. Full article

Background and Clinical Significance: Mastocytosis and mast cell activation syndrome (MCAS) include conditions in which patients manifest signs, symptoms, and laboratory findings consistent with mast cell activation and can only be diagnosed in the presence of specific criteria. Mutations of ZRSR2, a gene involved in RNA splicing, are not closely associated with mast cell disorders, but rather with myelodysplastic syndromes development. Case Presentation: We report a case of a 37-year-old man who was referred to our institution for anaphylaxis after a bee sting and elevated serum tryptase levels (17.8 ng/mL in the first sample and 19.2 ng/mL in the second sample). Complete blood count was unremarkable. Bone marrow biopsy showed signs of dysplasia and some CD25+ mast cells. ASO-qPCR and targeted myeloid NGS analysis did not detect the KIT p.D816V mutation, but rather showed the presence of a pathogenetic variant of the ZRSR2 gene (p.S447_R448del) with a variant allele frequency of 7.4%. Mastocytosis could not be diagnosed based on the established diagnostic criteria. The patient’s symptoms were not recurrent and tryptase release was not event-related; therefore, a diagnosis of MCAS could not be made either. Taken together, these findings led to the diagnosis of clonal hematopoiesis of indeterminate potential (CHIP). A watch and wait strategy consisting of clinical evaluations, blood tests, and cardiovascular risk assessment was initiated. Conclusions: This case report highlights the importance of combining clinical and laboratory findings, hematopathology, and molecular analyses to establish the most probable diagnosis in challenging cases. It also underscores the possible relevance of identifying predisposing conditions, such as CHIP, in order to guide counseling and follow-up strategy. Full article

Imatinib (IMT) is a small-molecule tyrosine kinase inhibitor that primarily targets platelet-derived growth factor receptor-β and related kinases. Beyond its established efficacy in chronic myeloid leukemia, IMT has also demonstrated therapeutic benefits in gastrointestinal stromal tumors, dermatofibrosarcoma, acute lymphoblastic leukemia, and as a second-line treatment for aggressive systemic mastocytosis or as an anti-Mycobacterium agent. From a physicochemical perspective, IMT exhibits poor aqueous solubility but high membrane permeability, classifying it as a Biopharmaceutics Classification System Class II compound. Pharmacokinetically, IMT shows variable oral absorption and a prolonged terminal half-life, resulting in dose-dependent systemic exposure. Despite relatively high oral bioavailability, its clinical use requires large doses to achieve therapeutic efficacy, underscoring the need for advanced drug delivery strategies. Nano- and microscale delivery systems offer promising approaches to enhance tumor-specific accumulation through the enhanced permeability and retention effect while mitigating resistance mechanisms. However, achieving high drug loading introduces formulation challenges, such as controlling particle size distribution, polydispersity, and scalability. Moreover, designing carriers capable of controlled release without premature leakage remains crucial for maintaining systemic bioavailability and therapeutic performance. Emerging delivery platforms—including polymeric, lipid-based, carbon-derived, and stimuli-responsive nanocarriers—have shown significant potential in overcoming these limitations. Such systems can enhance IMT’s bioavailability, improve selective tumor targeting, and minimize systemic toxicity, thereby advancing its translational potential. This review aims to highlight the different biomedical applications of IMT and off-label uses, and to discuss current advances in drug delivery to optimize its clinical efficacy and safety profile. Full article

Sex and gender play a critical role in allergic diseases, influencing immune response, clinical phenotypes, treatment strategies, outcomes, and health-related quality of life. Despite mounting evidence across multiple studies examining sex/gender differences in a multitude of allergic diseases, most address isolated conditions, not taking into consideration the vast interplay of hormonal, genetic, immunological, and sociocultural factors and their unique consequences for clinicians and researchers. With this position paper, we aim to assess currently available evidence on the sex- and gender-specific characteristics of the most common allergic diseases, providing an overview of present knowledge and future areas of improvement for clinicians and researchers. This position paper was developed by the Società Italiana di Allergologia, Asma ed Immunologia Clinica (SIAAIC): a panel of experts who conducted a literature review focusing on sex and gender differences across major allergic diseases. A consensus-based approach was employed to assess the immunological, clinical, and therapeutic implications of available evidence, offering a recommendation for researchers and clinicians alike. Data highlights marked differences driven by sex and gender in disease prevalence, immune pathways, clinical phenotype and severity, as well as therapeutic outcomes. Female patients appear to show a higher prevalence of Th2-driven ailments, autoimmune overlap, and allergic drug reactions, whereas males are more likely to experience fatal anaphylaxis and severe mastocytosis. Sex hormones can modulate multiple immune pathways leading to mast cell activation, antibody production, and cytokine expression, thus contributing to divergent disease trajectories. In conclusion, sex and gender are a key determinant in allergic diseases, and their integration in future research is essential to develop a tailored approach to treatment. Efforts should prioritise the identification of sex- and gender-specific biomarkers, therapeutic strategies, and equitable access to healthcare services. A sex- and gender-aware approach could potentially improve outcomes, optimise treatment strategies, and address current gaps in allergy practice. Full article

Mast cells have been implicated in allergic diseases such as asthma, rhinitis, conjunctivitis, atopic dermatitis, urticaria, and anaphylaxis. However, it is now well established that they also fulfill critical roles in tissue homeostasis, repair, and defense. Despite considerable progress, their ontogeny, proliferation, and differentiation remain subjects of debate, as does their involvement in a wide spectrum of diseases, including cancer and cardiovascular disorders. What remains indisputable is their essential contribution to both innate and adaptive immune responses. Importantly, the activity of their effector molecules can elicit either protective or deleterious outcomes. A complete absence of mast cells (MCs) in humans would undoubtedly provide valuable insight into their fundamental role in immunity, much as neutropenia and agranulocytosis have historically clarified the functions of neutrophils. In this review, we provide a comprehensive overview of mast cell (MC) biology, emphasizing their functional diversity and pathogenic potential. Furthermore, we highlight emerging therapeutic strategies, particularly the use of inhibitors and monoclonal antibodies, which are reshaping current approaches to conditions such as allergy, mastocytosis, and related disorders. Full article

Background: Patients with mastocytosis may present with exacerbated respiratory symptoms and lung diseases resulting from mast cell mediator release. However, their prevalence and severity level remain under debate. The study aims to analyze the prevalence of respiratory symptoms and the usefulness of lung function tests like spirometry, diffusing capacity of the lung for carbon monoxide (DLCO), and high-resolution computed tomography (HRCT) of the chest in mastocytosis patients presenting with dyspnea, cough, and exercise intolerance. Methods: We included 104 patients with mastocytosis and 71 healthy controls. Data collection encompassed patient interview, clinical examination, spirometry, DLCO, and chest HRCT. Diagnosis of mastocytosis included bone marrow biopsies and serum tryptase measurements. Results: Compared to controls, patients with mastocytosis exhibited significantly lower values in FEV1/VC ratio, absolute DLCO/VA, predicted DLCO/VA, absolute DLCOcSB, and predicted DLCOcSB (p < 0.001). Commonly reported respiratory symptoms included dyspnea (36.5%), chest tightness (22.1%), and wheezing (9.6%). Airway obstruction was identified in 7.7% of patients; however, it appeared to be independent of the mastocytosis subtype. A decreased DLCO/VA ratio was observed in 4.8% of patients, but HRCT did not reveal any evidence of underlying lung disease. Conclusions: Mastocytosis appears to be a risk factor for the occurrence and exacerbation of respiratory symptoms. However, airway obstruction and impairment of the alveolar–capillary membrane seem to occur independently of the clinical subtype of mastocytosis. Additionally, the causal relationship between pulmonary involvement, mast cell infiltration of the alveolar–capillary membrane, and the systemic circulation of mast cell mediators remains unclear and requires further research. Full article

Systemic mastocytosis (SM) is a rare and heterogeneous disorder characterized by clonal proliferation and accumulation of neoplastic mast cells in one or more organs, most commonly the bone marrow, liver, spleen, and skin. Among its clinical variants, aggressive SM (ASM) presents organ damage and debilitating symptoms due to extensive mast cell infiltration. The management of ASM remains challenging, primarily because treatment must address both symptom control and disease progression. Background/Objectives: Recent therapeutic approaches have focused on tyrosine kinase inhibitors (TKIs) that target the oncogenic KIT driver mutation, predominantly the D816V mutation, which is implicated in mast cell proliferation. We report a case series of four patients diagnosed with ASM to highlight the real-world experience in the management of ASM. All patients had confirmed KIT D816V mutations and presented with signs of advanced organ dysfunction, such as marked hepatosplenomegaly, cytopenia, and significant bone marrow infiltration. First-line therapies, including cytoreductive agents or other TKIs were used. Responses varied in these patients, and ultimately, they were initiated on or transitioned to midostaurin, a multikinase TKI. Results: All four patients, after the initiation of midostaurin, presented clinical and biological improvement—at least a clinical improvement response according to the International Working Group-Myeloproliferative Neoplasms Research and Treatment & European Competence Network on Mastocytosis (IWG-MRT-ECNM) criteria. These findings highlight the benefits of KIT inhibition in managing ASM, especially for patients with inadequate responses to traditional therapies. The impact of midostaurin on organ function, mast cell burden, and symptom control emphasizes the importance of the timely integration of TKIs into therapeutic protocols. However, optimal treatment duration, long-term safety, and the development of acquired resistance remain critical questions that warrant further studies. Larger prospective trials are needed to better delineate the prognostic factors associated with sustained response, refine patient selection, and explore combination strategies that may enhance therapeutic efficacy. Conclusions: The patients presented in this case series benefited from midostaurin therapy, showing either a clinical improvement or partial response according to the IWG-MRT-ECNM criteria. Our case series illustrates that KIT inhibitors can offer meaningful clinical benefit in ASM, reinforcing their position as an emerging cornerstone option in ASM management. Full article

Hereditary α-tryptasemia (HαT)—a genetic trait caused by increased α-tryptase-encoding typtase alpha/beta-1 (TPSAB1) copy number—is associated with adult mastocytosis. The primary objective was to assess the association between α-tryptase and pediatric mastocytosis. We also want to evaluate whether the KIT p.D816V mutation in peripheral blood leukocytes (PBLs) reliably predicts systemic mastocytosis (SM) in children. A prospective cohort of 68 children from a referral center in Slovenia with cutaneous mastocytosis (CM) underwent tryptase genotyping by droplet digital PCR and examination for KIT p.D816V in PBL using a sensitive PCR test. A significant majority of patients (57 of 68; [83.8%]) had at least one α-tryptase-encoding gene; none had HαT. 7 of the 68 (10.3%) who were positive for KIT p.D816V in PBL, one fulfilled diagnostic criteria for indolent SM, and another was diagnosed with monoclonal mast cell activation syndrome. One of those individuals had an increased basal serum tryptase (BST) level (14.5 ng/mL). We found a high presence of germline α-tryptase in children with CM, but not HαT. By employing sensitive examination for KIT p.D816V in PBL, in combination with clinical data and other examinations, our study suggests that KIT p.D816V in PBL may indicate systemic disease in children with CM. Full article

Mastocytosis is a heterogeneous group of disorders, distinguished by the monoclonal proliferation of mast cells (MCs) in one or more organs. While cutaneous mastocytosis (CM) is restricted to the skin, systemic mastocytosis (SM) presents with high MC infiltration of various organs. Indolent systemic mastocytosis (ISM) is the most common form in individuals with adult-onset of the disease. Bone health impairment is present in the vast majority of patients, ranging from osteoporosis to osteosclerosis, often presenting with fragility fractures. In this review, we comprehensively examine the impact of ISM on bone health, with particular emphasis on the molecular and cellular mechanisms underlying skeletal involvement, the clinical heterogeneity of bone manifestations, and the limitations of current diagnostic tools, while also evaluating emerging therapeutic strategies that target both MC activity and bone remodeling pathways. Full article