Longitudinal cytokine and multi-modal health data of an extremely severe ME/CFS patient with HSD reveals insights into immunopathology, and disease severity

Introduction

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) presents substantial challenges in patient care due to its intricate multisystem nature, comorbidities, and global prevalence. The heterogeneity among patient populations, coupled with the absence of FDA-approved diagnostics and therapeutics, further complicates research into disease etiology and patient managment. Integrating longitudinal multi-omics data with clinical, health,textual, pharmaceutical, and nutraceutical data offers a promising avenue to address these complexities, aiding in the identification of underlying causes and providing insights into effective therapeutics and diagnostic strategies.

Methods

This study focused on an exceptionally severe ME/CFS patient with hypermobility spectrum disorder (HSD) during a period of marginal symptom improvements. Longitudinal cytokine profiling was conducted alongside the collection of extensive multi-modal health data to explore the dynamic nature of symptoms, severity, triggers, and modifying factors. Additionally, an updated severity assessment platform and two applications, ME-CFSTrackerApp and LexiTime, were introduced to facilitate real-time symptom tracking and enhance patient-physician/researcher communication, and evaluate response to medical intervention.

Results

Longitudinal cytokine profiling revealed the significance of Th2-type cytokines and highlighted synergistic activities between mast cells and eosinophils, skewing Th1 toward Th2 immune responses in ME/CFS pathogenesis, particularly in cognitive impairment and sensorial intolerance. This suggests a potentially shared underlying mechanism with major ME/CFS comorbidities such as HSD, Mast cell activation syndrome, postural orthostatic tachycardia syndrome (POTS), and small fiber neuropathy. Additionally, the data identified potential roles of BCL6 and TP53 pathways in ME/CFS etiology and emphasized the importance of investigating adverse reactions to medication and supplements and drug interactions in ME/CFS severity and progression.

Discussion

Our study advocates for the integration of longitudinal multi-omics with multi-modal health data and artificial intelligence (AI) techniques to better understand ME/CFS and its major comorbidities. These findings highlight the significance of dysregulated Th2-type cytokines in patient stratification and precision medicine strategies. Additionally, our results suggest exploring the use of low-dose drugs with partial agonist activity as a potential avenue for ME/CFS treatment. This comprehensive approach emphasizes the importance of adopting a patient-centered care approach to improve ME/CFS healthcare management, disease severity assessment, and personalized medicine. Overall, these findings contribute to our understanding of ME/CFS and offer avenues for future research and clinical practice.

Reversible Elevation of Tryptase Over the Individual's Baseline: Why is It the Best Biomarker for Severe Systemic Mast Cell Activation and MCAS?

PURPOSE OF REVIEW

Mast cell (MC) activation syndromes (MCAS) are conditions defined by recurrent episodes of severe systemic anaphylaxis or similar systemic events triggered by MC-derived mediators that can be measured in biological fluids. Since some symptoms of MC activation may occur due to other, non-MC etiologies and lead to confusion over diagnosis, it is of crucial importance to document the involvement of MC and their products in the patients´ symptomatology.

RECENT FINDINGS

The most specific and generally accepted marker of severe systemic MC activation is an event-related, transient increase in the serum tryptase level over the individual baseline of the affected individual. However, baseline concentrations of serum tryptase vary among donors, depending on the genetic background, age, kidney function, and underlying disease. As a result, it is of critical importance to provide a flexible equation that defines the diagnostic increase in tryptase qualifying as MCAS criterion in all patients, all situations, and all ranges of baseline serum tryptase. In 2012, the consensus group proposed the 120% + 2 ng/ml formula, which covers the great majority of groups, including cases with low, normal, or elevated basal serum tryptase level. This formula has been validated in subsequent studies and has proven to be a robust and consistent diagnostic criterion of MCAS. The present article is discussing the impact of this formula and possible limitations as well as alternative markers and mediators that may be indicative of MCAS.

Low Prevalence of Idiopathic Mast Cell Activation Syndrome Among 703 Patients With Suspected Mast Cell Disorders

BACKGROUND

Idiopathic mast cell activation syndrome (iMCAS) is characterized by severe, episodic systemic mast cell (MC) activation and mediator-related symptoms, an event-related increase in serum tryptase levels, and response to MC-targeted therapies in the absence of underlying IgE-mediated allergy or clonal MC disorder. Studies indicating its prevalence using evidence-based diagnostic criteria are lacking.

OBJECTIVE

To assess the prevalence and clinical and laboratory features of patients with iMCAS.

METHODS

We conducted a retrospective evaluation of data from 703 consecutive patients (aged ≥18 years) referred to our center based on suspicion of having MC disorders. Patients underwent a thorough clinical workup including patient history, allergy tests, KIT D816V mutation analysis, and/or bone marrow investigation. Disease activity was prospectively assessed during follow-up visits.

RESULTS

We identified 31 patients with confirmed iMCAS. Furthermore, hereditary α-tryptasemia was detected in three patients with baseline tryptase levels greater than 8 ng/mL. The most common clinical presentation during MCAS episodes was mucocutaneous symptoms in patients with iMCAS, especially urticaria or angioedema. However, these symptoms were less prevalent in patients with clonal MCAS (P = .015). The duration of diagnostic delay was significantly longer in patients with iMCAS compared to those with clonal MCAS (P = .02).

CONCLUSIONS

The overall prevalence of iMCAS was 4.4% in the entire cohort, which indicates that iMCAS is an uncommon condition. To accurately diagnose iMCAS, it is crucial to evaluate suspected patients using the three diagnostic MCAS criteria. This involves performing a comprehensive allergy work-up including laboratory tests and ultrasensitive mutation analysis of KIT D816V. Subsequently, recommended diagnostic algorithms should be applied.

Using the Right Criteria for MCAS

PURPOSE OF REVIEW

The current article aims to provide a comprehensive update on diagnostic criteria for mast cell activation syndrome (MCAS), addressing challenges in diagnosing and classifying MCAS and its variants.

RECENT FINDINGS

In recent years, there has been a significant increase in our knowledge regarding the underlying mechanisms responsible for the activation of mast cells (MCs) in various pathological conditions. Furthermore, a set of criteria and a classification for MCASs have been established. MCAS is characterized by the presence of typical clinical symptoms, a substantial elevation in serum tryptase levels during an attack compared to the patient's baseline tryptase levels, and a response to MC mediator-targeting therapy. In this report, a thorough examination was conducted on the contemporary literature relating to MCAS, with a focus on comparing the specificity, sensitivity, and robustness of MCAS-related parameters within proposals for diagnosing and classifying MCAS and its variants. Moreover, the significance of employing specific consensus criteria in the assessment and categorization of MCAS in individual patients was underscored, due to the escalating occurrence of patients receiving a misdiagnosis of MCAS based on nonspecific criteria.

Diagnostic Significance of Tryptase for Suspected Mast Cell Disorders

Tryptase has proven to be a very useful and specific marker to demonstrate mast cell activation and degranulation when an acute (i.e., within 4 h after the event) and baseline value (i.e., at least 24 h after the event) are compared and meet the consensus formula (i.e., an increase of 20% + 2). The upper limit of normal determined by the manufacturer is 11.4 ng/mL; however, this boundary has been the subject of debate. According to ECNM and AIM experts, the normal range of baseline tryptase should be 1 to 15 ng/mL. A genetic trait, hereditary alpha tryptasemia, characterized by an increased alpha coding TPSAB1 copy number is associated with a baseline value above 8 ng/mL. Elevated tryptase can also be found in chronic kidney disease, obesity, and hematological neoplasms. A tryptase > 20 ng/mL serves as a minor criterion to diagnose systemic mastocytosis and an increase in tryptase > 20% + 2 during an acute event is a required criterion in the diagnosis of mast cell activation syndrome. The goal of this review is to demonstrate the (in)significance of tryptase using some clinical vignettes and to provide a practical guide on how to manage and interpret an elevated tryptase level.

Management of Mediator Symptoms, Allergy, and Anaphylaxis in Mastocytosis

Mastocytosis is characterized by expansion and activation of clonally aberrant mast cells (MCs) in one or more organ systems. Inappropriate MC activation is a key finding in both allergy and mastocytosis; therefore, symptoms in both conditions show some degree of overlap. When mediator release is excessive and involves multiple systems, anaphylaxis may occur. In mastocytosis, the prevalence of atopy is similar to those of the general population, whereas the incidence of anaphylaxis is significantly higher. The purpose of this review is to discuss features of allergy and anaphylaxis as well as the principles of managing MC mediator release symptoms in mastocytosis.

A Puzzling Mast Cell Trilogy: Anaphylaxis, MCAS, and Mastocytosis

Our knowledge of biology and mast cell (MC) function, as well as disorders associated with the pathologic activation of MCs, has evolved over the last few decades. Anaphylaxis, mast cell activation syndrome (MCAS), and mastocytosis are interrelated yet distinct conditions within the spectrum of mast cell activation disorders. Nevertheless, all three conditions can co-exist in one and the same patient, as pathologic MC activation is the key finding in all three. When mediator release is excessive and involves multiple systems, anaphylaxis and MCAS may occur. Furthermore, mastocytosis is a clonal disorder of MCs and often presents with anaphylaxis and MCAS. Nevertheless, in some cases, even the proliferative and accumulative features of MCs in mastocytosis can account for symptoms and disease progression. In each case, diagnosis can be only made when the diagnostic consensus criteria are fulfilled. The current article aims to provide a concise clinical update and pinpoint the main difficulties in diagnosing these puzzling disorders of MCs in medical practice.

Mastocytosis and related entities: a practical roadmap

Mastocytosis is a complex heterogenous multisystem disorder that is characterized by pathologic activation or accumulation of neoplastic mast cells (MCs) in one or more organs. This clonal MC expansion is often associated with a somatic gain-of-function mutation (D816V in most of the cases) in the KIT gene, encoding for the MC surface receptor KIT (CD117), a stem cell growth factor receptor. Based on clinical and biochemical criteria, the World Health Organization (WHO) divided mastocytosis into different subclasses. The exact prevalence of mastocytosis remains elusive, but it is estimated that the disease affects approximately 1 in 10,000 persons. The clinical presentation of mastocytosis varies significantly, ranging from asymptomatic patients to a life-threatening disease with multiple organ involvement, potentially leading to cytopenia, malabsorption, hepatosplenomegaly, lymphadenopathy, ascites or osteolytic bone lesions with pathological fractures. Patients with mastocytosis may experience symptoms related to release of MC mediators, such as flushing or diarrhea or even more severe symptoms such as anaphylaxis. Recently, a new genetic trait, hereditary alpha tryptasemia (HaT), was described which involves a copy number variation in the TPSAB1-gene. Its role as standalone multisystem syndrome is heavily debated. There is emerging evidence suggesting there might be a link between HaT and due to the increased prevalence of HaT in patients with SM. The aim of this review is to provide a practical roadmap for diagnosis and management of mastocytosis and its associated entities, since there are still many misconceptions about these topics.Abbreviations: AdvSM: Advanced systemic mastocytosis; ASM: Aggressive systemic mastocytosis; aST: acute serum tryptase; BM: Bone marrow; BMM: Bone marrow mastocytosis; bST: baseline serum tryptase; CM: Cutaneous mastocytosis; DCM: Diffuse cutaneous mastocytosis; HVA: Hymenoptera venom allergy; HaT: Hereditary alpha tryptasemia; ISM: Indolent systemic mastocytosis; MC: Mast cell; MCA: Mast cell activation; MCAS: Mast cell activation syndrome; MCL: Mast cell leukemia; MIS: Mastocytosis in the skin; MMAS: Monoclonal mast cell activation syndrome; MPCM: Maculopapular cutaneous mastocytosis; SM: Systemic mastocytosis; SM-AHN: Systemic mastocytosis with associated hematological neoplasm; SSM: Smouldering systemic mastocytosis; VIT: Venom immunotherapy.

Mast Cell Activation Syndrome Update-A Dermatological Perspective

Mast cells (MCs) are infamous for their role in potentially fatal anaphylaxis reactions. In the last two decades, a more complex picture has emerged, as it has become obvious that MCs are much more than just IgE effectors of anaphylaxis. MCs are defenders against a host of infectious and toxic aggressions (their interactions with other components of the immune system are not yet fully understood) and after the insult has ended, MCs continue to play a role in inflammation regulation and tissue repair. Unfortunately, MC involvement in pathology is also significant. Apart from their role in allergies, MCs can proliferate clonally to produce systemic mastocytosis. They have also been implicated in excessive fibrosis, keloid scaring, graft rejection and chronic inflammation, especially at the level of the skin and gut. In recent years, the term MC activation syndrome (MCAS) was proposed to account for symptoms caused by MC activation, and clear diagnostic criteria have been defined. However, not all authors agree with these criteria, as some find them too restrictive, potentially leaving much of the MC-related pathology unaccounted for. Here, we review the current knowledge on the physiological and pathological roles of MCs, with a dermatological emphasis, and discuss the MCAS classification.

European Competence Network on Mastocytosis (ECNM): 20-Year Jubilee, Updates, and Future Perspectives

In 2002, the European Competence Network on Mastocytosis (ECNM) was launched as a multidisciplinary collaborative initiative to increase the awareness and to improve diagnosis and management of patients with mast cell (MC) disorders. The ECNM consists of a net of specialized centers, expert physicians, and scientists who dedicate their work to MC diseases. One essential aim of the ECNM is to timely distribute all available information about the disease to patients, doctors, and scientists. In the past 20 years, the ECNM has expanded substantially and contributed successfully to the development of new diagnostic concepts, and to the classification, prognostication, and treatments of patients with mastocytosis and MC activation disorders. The ECNM also organized annual meetings and several working conferences, thereby supporting the development of the World Health Organization classification between 2002 and 2022. In addition, the ECNM established a robust and rapidly expanding patient registry and supported the development of new prognostic scoring systems and new treatment approaches. In all projects, ECNM representatives collaborated closely with their U.S. colleagues, various patient organizations, and other scientific networks. Finally, ECNM members have started several collaborations with industrial partners, leading to the preclinical development and clinical testing of KIT-targeting drugs in systemic mastocytosis, and some of these drugs received licensing approval in recent years. All these networking activities and collaborations have strengthened the ECNM and supported our efforts to increase awareness of MC disorders and to improve diagnosis, prognostication, and therapy in patients.

Cluster-Analytic Identification of Clinically Meaningful Subtypes in MCAS: The Relevance of Heat and Cold

BACKGROUND

Mast cell activation syndrome (MCAS) is a clinically heterogeneous disease with allergy-like symptoms and abdominal complaints. Its etiology is only partially understood and it is often overlooked.

AIMS

The aim of this study was to identify subgroups of MCAS patients to facilitate diagnosis and allow a personalized therapy.

METHODS

Based on data from 250 MCAS patients, hierarchical and two-step cluster analyses as well as association analyses were performed. The data used included data from a MCAS checklist asking about symptoms and triggers and a set of diagnostically relevant laboratory parameters.

RESULTS

Using a two-step cluster analysis, MCAS patients could be divided into three clusters. Physical trigger factors were particularly decisive for the classification as they showed remarkable differences between the three clusters. Cluster 1, labeled high responders, showed high values for the triggers heat and cold, whereas cluster 2, labeled intermediate responders, presented with high values for the trigger heat and low values for cold. The third cluster, labeled low responders, did not react to thermal triggers. The first two clusters showed more divers clinical symptoms especially with regard to dermatological and cardiological complaints. Subsequent association analyses revealed relationships between triggers and clinical complaints: Abdominal discomfort is mainly triggered by histamine consumption, dermatological discomfort by exercise, and neurological symptoms are related to physical exertion and periods of starvation. The reasons for the occurrence of cardiological complaints are manifold and triggers for respiratory complaints still need better identification.

CONCLUSION

Our study identified three distinct clusters on the basis of physical triggers, which also differ significantly in their clinical symptoms. A trigger-related classification can be helpful in clinical practice for diagnosis and therapy. Longitudinal studies should be conducted to further understand the relationship between triggers and symptoms.

Immunological dysfunction and mast cell activation syndrome in long COVID

At least 65 million people around the world suffer from long COVID-19, with the majority of cases occurring in the productive age (36-50 years old). Individuals with long COVID-19 are confounded with multiple organ system dysfunctions, long-term organ injury sequelae, and a decreased quality of life. There is an overlapping of risk factors between long COVID-19 and other postviral infection syndromes, so advances in research could also benefit other groups of patients. Long COVID-19 is the consequence of multiple immune system dysregulation, such as T-cell depletion, innate immune cell hyperactivity, lack of naive T and B cells, and elevated signature of pro-inflammatory cytokines, together with persistent severe acute respiratory syndrome-coronavirus 2 reservoir and other consequences of acute infection. There is an activated condition of mast cells in long COVID-19, with abnormal granulation and excessive inflammatory cytokine release. A study by Weinstock et al. indicates that patients with long COVID-19 suffer the same clinical syndrome as patients with mast cell activation syndrome (MCAS). Diagnosis and treatment of MCAS in patients with long COVID-19 will provide further symptomatic relief, and manage mast cell-mediated hyperinflammation states, which could be useful in the long-term control and recovery of such patients.

Idiopathic mast cell activation syndrome is more often suspected than diagnosed-A prospective real-life study

BACKGROUND

Idiopathic mast cell activation syndrome (MCAS) is characterized by three diagnostic criteria: (1) episodic mast cell (MC)-driven signs/symptoms of at least two organ systems in the absence of clonal MC expansion and definite triggers, (2) episodic increase in tryptase, and (3) response to MC-targeted treatment. Many patients believe they have MCAS, but how often this is the case remains unknown.

METHODS

We prospectively investigated patients with suspected MCAS (n = 100) for the diagnostic criteria including baseline tryptase, KIT D816V mutation, and patient-reported outcome measures (PROMs) over the course of 12 weeks. Comorbid depression and anxiety were explored with the Hospital Anxiety and Depression Scale (HADS).

RESULTS

In 53% of our patients (80% females), suspicion of MCAS was based on self-evaluation. In total, patients reported 87 different symptoms, mostly fatigue (n = 57), musculoskeletal pain/weakness (n = 49), and abdominal pain (n = 43), with overall high disease activity and impact. Two of 79 patients had increased tryptase (by >20% +2 ng/ml) following an episode. Only 5%, with any of the PROMs used, showed complete response to MC-targeted treatment. Depression and anxiety disorders were frequent comorbidities (n = 23 each), and 65 patients had pathological HADS values, which were linked to high disease impact and poor symptom control.

CONCLUSION

Mast cell activation syndrome was confirmed in only 2% of patients, which implies that it is not MC activation that drives signs and symptoms in most patients with suspected MCAS. There is a high need for comprehensive research efforts aimed at the identification of the true underlying pathomechanism(s) in patients with suspected MCAS.

Global Classification of Mast Cell Activation Disorders: An ICD-10-CM-Adjusted Proposal of the ECNM-AIM Consortium

Mast cell activation (MCA) is common and occurs in a number of pathologic conditions, including IgE-dependent and independent allergic reactions, atopic disorders, autoimmune processes, and mastocytosis. In a subset of patients, no underlying disease and no known trigger of MCA are found. When the symptoms are severe, systemic, and recurrent, and accompanied by a diagnostic increase in the serum tryptase level or other mast cell mediators, an MCA syndrome (MCAS) may be diagnosed. In these patients, the symptoms typically respond to drugs suppressing MCA, mediator production in mast cells, or mediator effects. In each case, diagnostic consensus criteria must be fulfilled to diagnose MCAS. In other patients, MCA may be local, less severe, or less acute, or may be suspected but not confirmed, so that the diagnostic criteria of MCAS are not fulfilled. In these patients, it may be difficult to prove MCA, for example, by measuring multiple mast cell mediators or basophil activation, the latter as a surrogate of IgE-dependent hypersensitivity. However, validated diagnostic criteria for implicating suspected MCA behind such conditions are lacking, even if some of these conditions have recently been assigned to an International Classification of Diseases-10-Clinical Modification code (ICD-10-CM). In this article, we discuss diagnostic features and criteria and propose a ICD-10-CM-adjusted classification for disorders associated with MCA, herein referred to as MCA disorders (MCADs), with special emphasis on the delineation between confirmed MCAS, MCAD not fulfilling MCAS criteria, and suspected MCAD that is not present. In addition, we discuss the discrimination between overt MCAD and predisposing conditions, such as atopic states, mastocytosis, and hereditary alpha tryptasemia.

Drug-Induced Mast Cell Eradication: A Novel Approach to Treat Mast Cell Activation Disorders?

Mast cell activation is a key event in allergic reactions, other inflammatory states, and mast cell activation syndromes. Mast cell-stabilizing agents, mediator-targeting drugs and drugs interfering with mediator effects are often prescribed in these patients. However, the clinical efficacy of these drugs varies, depending on the numbers of involved mast cells and the underlying pathology. One straightforward approach would be to eradicate the primary target cell. However, to date, no mast cell-eradicating treatment approach has been developed for patients suffering from mast cell activation disorders. Nevertheless, recent data suggest that long-term treatment with agents that effectively inhibit KIT-function results in the virtual eradication of tissue mast cells and a sustained decrease in serum tryptase levels. In many of these patients, mast cell depletion is associated with a substantial improvement in mediator-induced symptoms. In patients with an underlying KIT D816V+ mastocytosis, such mast cell eradication requires an effective inhibitor of KIT D816V, such as avapritinib. However, the use of KIT inhibitors must be balanced against potential side effects. We here discuss mast cell-eradicating strategies in various disease models, the feasibility of this approach, available clinical data, and future prospects for the use of KIT-targeting drugs in mast cell activation disorders.

Personalized Management Strategies in Mast Cell Disorders: ECNM-AIM User's Guide for Daily Clinical Practice

Mastocytosis is a myeloid neoplasm defined by expansion and focal accumulation of clonal mast cells (MCs) in one or more organs. The disease exhibits a complex pathology and may be complicated by MC activation, bone abnormalities, neurological problems, gastrointestinal symptoms, and/or hematologic progression. The World Health Organization divides mastocytosis into cutaneous forms, systemic mastocytosis (SM) and MC sarcoma. In most patients with SM, somatic mutations in KIT are detected. Patients with indolent SM have a normal to near-normal life expectancy, whereas patients with advanced SM, including aggressive SM and MC leukemia, have a poor prognosis. In those with advanced SM, multiple somatic mutations and an associated hematologic neoplasm may be detected. Mediator-related symptoms can occur in any type of mastocytosis. Symptoms may be mild, severe, or even life-threatening. In patients with severe acute symptoms, an MC activation syndrome may be diagnosed. In these patients, relevant comorbidities include IgE-dependent and IgE-independent allergies. Management of patients with SM is an emerging challenge in daily practice and requires in-depth knowledge and a multidisciplinary and personalized approach with selection of appropriate procedures and interventions. In this article, we review the current knowledge on SM and MC activation syndrome, with emphasis on multidisciplinary aspects in diagnosis and patient-specific management. In addition, we provide a user's guide for application of markers, algorithms, prognostic scores, and treatments for use in daily practice.

Selecting the Right Criteria and Proper Classification to Diagnose Mast Cell Activation Syndromes: A Critical Review

In recent years, knowledge about mechanisms underlying mast cell activation (MCA) and accumulation in various pathologic conditions increased substantially. In addition, criteria and a classification of MCA syndromes (MCASs) have been set forth. MCAS is defined by typical clinical symptoms, a substantial increase in serum tryptase level during an attack over the patient's baseline tryptase, and a response of the symptoms to drugs targeting mast cells, mediator production, and/or mediator effects. Alternative diagnostic criteria of MCAS have also been suggested, but these alternative criteria often lack specificity and validation. In this report, we critically review the contemporary literature relating to MCAS and compare the specificity, sensitivity, and strength of MCAS-related parameters within proposals to diagnose and classify MCAS and its variants. Furthermore, we highlight the need to apply specific consensus criteria in the evaluation and classification of MCAS in individual patients. This is an urgent and important medical necessity because as an increasing number of patients are being given a misdiagnosis of MCAS based on nonspecific criteria, which contributes to confusion and frustration by patients and caregivers and sometimes may delay recognition and treatment of correct medical conditions that often turn out to be unrelated to MCA.

Mast Cell Activation Syndrome: A Primer for the Gastroenterologist

Mast cell activation syndrome is thought to be a common, yet under-recognized, chronic multi-system disorder caused by inappropriate mast cell activation. Gastrointestinal symptoms are frequently reported by these patients and are often mistaken by physicians as functional gastrointestinal disorders. This syndrome can be diagnosed by the medical history and measurable biomarkers. Gastroenterologists manage diseases associated with active inflammatory cells including neutrophils, lymphocytes, macrophages, and eosinophils. The mast cell has only recently been recognized as a major player in our specialty. Gastrointestinal disorders from mast cell mediators often present with apparent irritable bowel syndrome, dyspepsia, chronic or cyclical nausea, and heartburn. Individuals with mast cell activation syndrome experience significant delays in diagnosis. The gastrointestinal symptoms are often refractory to symptom-targeted prescription medications. Beyond avoiding triggers, the best therapy is directed at modulating mast cell activation and the effects of the mediators. Many of these therapies are simple over-the-counter medications. In this article, we review mast cell function and dysfunction and the gastrointestinal symptoms, comorbid conditions, diagnosis, and management of mast cell activation syndrome. Gastroenterologists who become aware of this syndrome can dramatically improve the quality of life for their patients who previously have been labeled with a functional gastrointestinal disorder.

Watershed subarachnoid hemorrhage after middle cerebral artery rescue stenting in patients with acute ischemic stroke

Cortical subarachnoid hemorrhage is an infrequent subtype of non-aneurysmal subarachnoid hemorrhage, rarely reported in watershed territories (wSAH) after carotid stenting. It has never been reported after treatment of middle cerebral artery stenosis (MCAS) that is increasingly used in selected patients, as rescue treatment of failed mechanical thrombectomy, due to recent advancements in endovascular interventions. We present a series of patients with MCAS that developed a wSAH after stenting.

A Challenge for Allergologist: Application of Allergy Diagnostic Methods in Mast Cell Disorders

Primary and secondary mast cell activation syndromes (MCAS) can occur in patients with mastocytosis. During the past few years our knowledge about the pathogenesis and disease-triggering mechanisms in MCAS and mastocytosis have increased substantially. Whereas mastocytosis is characterized by an accumulation of neoplastic (clonal) mast cells (MC) in various organ systems, MCAS is defined by a massive and systemic activation of these cells. Mast cells are crucial effector cells in allergic diseases, thus their elevated number and activation can cause severe anaphylactic reactions and MCAS in patients with mastocytosis. However, these cells may also degranulate spontaneously or degranulate in response to non-allergic triggers leading to clinical symptoms. In mastocytosis patients, such symptoms may lead to the diagnosis of a primary MCAS. The diagnosis of a concomitant allergy in mastocytosis patients is challenging. In these patients, a mixed form (primary and secondary) of MCAS may be diagnosed. These patients may also suffer from life-threatening anaphylactic reactions when exposed to allergens. In these cases, the possibility of severe side effects of in vivo provocations can sometimes also limit diagnostic evaluations. In the current article, we discuss the diagnosis and management of patients suffering from mastocytosis and concomitant MCAS, with special emphasis on novel diagnostic tests and management, including allergen microarrays, recombinant allergen analysis, basophil activation tests, optimal prophylaxis, and specific therapies.

Mast Cell Activation: When the Whole Is Greater than the Sum of Its Parts

Mast cell activation syndrome (MCAS) is a heterogeneous and rare disorder with episodic and severe activation of mast cells. Because symptoms of mast cell activation are nonspecific, it is important to base the diagnosis on best available clinical and scientific evidence, and not make it one of exclusion. MCAS, much like the mast cell itself, as a whole is greater than the sum of its proposed diagnostic criteria. When each component is considered in isolation, criteria can seem nonspecific, and thus, a broad constellation of symptoms can be attributed to MCAS when they may be due to other disease processes.

Multidisciplinary Challenges in Mastocytosis and How to Address with Personalized Medicine Approaches

Mastocytosis is a hematopoietic neoplasm defined by abnormal expansion and focal accumulation of clonal tissue mast cells in various organ-systems. The disease exhibits a complex pathology and an equally complex clinical behavior. The classification of the World Health Organization (WHO) divides mastocytosis into cutaneous forms, systemic variants, and localized mast cell tumors. In >80% of patients with systemic mastocytosis (SM), a somatic point mutation in KIT at codon 816 is found. Whereas patients with indolent forms of the disease have a normal or near-normal life expectancy, patients with advanced mast cell neoplasms, including aggressive SM and mast cell leukemia, have a poor prognosis with short survival times. In a majority of these patients, multiple somatic mutations and/or an associated hematologic neoplasm, such as a myeloid leukemia, may be detected. Independent of the category of mastocytosis and the serum tryptase level, patients may suffer from mediator-related symptoms and/or osteopathy. Depending on the presence of co-morbidities, the symptomatology in such patients may be mild, severe or even life-threatening. Most relevant co-morbidities in such patients are IgE-dependent allergies, psychiatric, psychological or mental problems, and vitamin D deficiency. The diagnosis and management of mastocytosis is an emerging challenge in clinical practice and requires vast knowledge, a multidisciplinary approach, and personalized medicine procedures. In this article, the current knowledge about mastocytosis is reviewed with special emphasis on the multidisciplinary aspects of the disease and related challenges in daily practice.

Proposed Diagnostic Algorithm for Patients with Suspected Mast Cell Activation Syndrome

Mast cell activation (MCA) accompanies diverse physiologic and pathologic processes and is one of the more frequently encountered conditions in medicine. MCA-related symptoms are usually mild and often transient. In such cases, histamine receptor blockers and other mediator-targeting drugs can usually control MCA. In severe cases, an MCA syndrome (MCAS) may be diagnosed. However, overt MCAS is an unusual condition, and many patients referred because of suspected MCAS are diagnosed with other diseases (autoimmune, neoplastic, or infectious) unrelated to MCA or suffer from MCA-related (eg, allergic) disorders and/or comorbidities without fulfilling criteria of an overt MCAS. These considerations are important as more and more patients are informed that they may have MCA or even MCAS without completing a thorough medical evaluation. In fact, in several instances, symptoms are misinterpreted as MCA/MCAS, and other clinically relevant conditions are not thoroughly pursued. The number of such referrals is increasing. To avoid such unnecessary referrals and to prevent misdiagnoses, we here propose a diagnostic algorithm through which a clinically relevant (systemic) MCA can be suspected and MCAS can subsequently be documented or excluded. In addition, the algorithm proposed should help guide the investigating care providers to consider the 2 principal diagnoses that may underlie MCAS, namely, severe allergy and systemic mastocytosis accompanied by severe MCA. Although validation is required, we anticipate that this algorithm will facilitate the management of patients with suspected MCAS.

Psychometric Properties of the Milestones of Recovery Scale-Older Adult Version

The Milestones of Recovery Scale (MORS) is a tool that mental health professionals can use to track clients' recovery. It has been shown to have good reliability and validity in an adult population. It is important to demonstrate its psychometric properties among the elderly. This study assessed the reliability and validity of the MORS among a multi-ethnic (52 % White) sample of adults 54 and older (M = 67) at several mental health agencies in California. The clients, N = 432, were assessed by two raters each at two time points 2 weeks apart. Ratings were obtained on the MORS, the modified Global Assessment of Functioning scale (mGAF), and the Multnomah Community Ability Scale (MCAS). The MORS demonstrated acceptable reliability: inter-rater r = .65 and test-retest r = .71; the mGAF was .56 and .79; the MCAS was .66 and .85. The validity of the MORS was also supported: mGAF-MORS r = .68 and MCAS-MORS r = .74. This study lends support for the use of the MORS in older adult populations. In addition, this is the first report of the psychometric properties of the MCAS with an entirely older adult sample.

Nonaggressive systemic mastocytosis (SM) without skin lesions associated with insect-induced anaphylaxis shows unique features versus other indolent SM

BACKGROUND

Indolent systemic mastocytosis (ISM) without skin lesions (ISMs(-)) shows a higher prevalence in males, lower serum baseline tryptase levels, and KIT mutation more frequently restricted to bone marrow (BM) mast cells (MCs) than ISM with skin lesions (ISMs(+)). Interestingly, in almost one-half of ISMs(-) patients, MC-mediator release episodes are triggered exclusively by insects.

OBJECTIVE

We aimed to determine the clinical and laboratory features of ISMs(-) associated with insect-induced anaphylaxis (insectISMs(-)) versus other patients with ISM.

METHODS

A total of 335 patients presenting with MC activation syndrome, including 143 insectISMs(-), 72 ISMs(-) triggered by other factors (otherISMs(-)), 56 ISMs(+), and 64 nonclonal MC activation syndrome, were studied.

RESULTS

Compared with otherISMs(-) and ISMs(+) patients, insectISMs(-) cases showed marked male predominance (78% vs 53% and 46%; P < .001), a distinct pattern of MC-related symptoms, and significantly lower median serum baseline tryptase levels (22.4 vs 28.7 and 45.8 μg/L; P ≤ .009). Moreover, insectISMs(-) less frequently presented BM MC aggregates (46% vs 70% and 81%; P ≤ .001), and they systematically showed MC-restricted KIT mutation.

CONCLUSIONS

ISMs(-) patients with anaphylaxis triggered exclusively by insects display clinical and laboratory features that are significantly different from other ISM cases, including other ISMs(-) and ISMs(+) patients, suggesting that they represent a unique subgroup of ISM with a particularly low BM MC burden in the absence of adverse prognostic factors.