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Thomas EG, Thomas DJ. Mimics of Allergy and Angioedema: Scombroid, Mast Cell Activation Disorders, and Hereditary Alpha Tryptasemia. Immunol Allergy Clin North Am 2023; 43:553-568. [PMID: 37394259 DOI: 10.1016/j.iac.2022.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Scombroid poisoning, systemic mastocytosis, and hereditary alpha tryptasemia all present with episodes that resemble allergic reactions. Knowledge regarding systemic mastocytosis and hereditary alpha tryptasemia is quickly evolving. Epidemiology, pathophysiology, and strategies to identify and diagnose are discussed. Evidence-based management in the emergency setting and beyond is also explored and summarized. Key differences are described between these events and allergic reactions.
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Affiliation(s)
- Elizabeth G Thomas
- Department of Emergency Medicine, Ochsner Medical Center, 1514 Jefferson Highway, Jefferson, New Orleans, LA 70121, USA.
| | - Daniel James Thomas
- Department of Emergency Medicine, Ochsner Medical Center, 1514 Jefferson Highway, Jefferson, New Orleans, LA 70121, USA
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2
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Jiang M, Vadas P. Hereditary alpha-tryptasemia and complete deletion of exon 8 of the c-kit gene in patients with mast cell activation syndrome. Leuk Lymphoma 2023; 64:1348-1351. [PMID: 37086476 DOI: 10.1080/10428194.2023.2203286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 03/16/2023] [Accepted: 04/11/2023] [Indexed: 04/24/2023]
Affiliation(s)
- Maggie Jiang
- Division of Allergy and Clinical Immunology, St. Michael's Hospital/University of Toronto, Toronto, Canada
| | - Peter Vadas
- Division of Allergy and Clinical Immunology, St. Michael's Hospital/University of Toronto, Toronto, Canada
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3
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Tiano R, Krase IZ, Sacco K. Updates in diagnosis and management of paediatric mastocytosis. Curr Opin Allergy Clin Immunol 2023; 23:158-163. [PMID: 36730855 DOI: 10.1097/aci.0000000000000869] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
PURPOSE OF REVIEW Paediatric mastocytosis is a rare clonal disorder characterized by the overproduction and organ infiltration of mast cells. Symptoms are due to mast cell mediator release. Cutaneous mastocytosis is the most common presentation in children with systemic disease being rare. Our aim is to provide a practical guideline in differentiating subtypes of paediatric mastocytosis while providing actionable recommendations on diagnosis, clinical management, follow-up and prognosis. RECENT FINDINGS Longitudinal cohort studies of paediatric cutaneous mastocytosis have shown spontaneous remission with favourable prognosis. Hereditary alpha-tryptasemia may coexist with mastocytosis; thus, screening for this disorder is recommended. There is an emerging role for serum tryptase in asthma endotyping and potential for using therapeutic tryptase inhibitors. SUMMARY Morbidity in paediatric mastocytosis typically arises from symptoms secondary to mast cell mediator release. Prognosis for nonaggressive disease is typically favourable; however, risks for anaphylaxis and psychosocial morbidity may be underestimated. Symptomatic management and anticipatory guidance may help support patients and families throughout the disease course.
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Affiliation(s)
- Rasa Tiano
- Division of Pulmonology, Section of Allergy-Immunology, Phoenix Children's Hospital, Phoenix
| | - Ifat Z Krase
- Division of Pulmonology, Section of Allergy-Immunology, Phoenix Children's Hospital, Phoenix
- Divison of Allergy-Immunology, Mayo Clinic, Scottsdale
| | - Keith Sacco
- Division of Pulmonology, Section of Allergy-Immunology, Phoenix Children's Hospital, Phoenix
- Department of Child Health, University of Arizona College of Medicine, Phoenix, Arizona, USA
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4
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Cochran AL, Coop C, Neaves BI, Wood ST. The Curious Case of Elevated Tryptase: Workup and Differential in Family of Four. Cureus 2023; 15:e38065. [PMID: 37228529 PMCID: PMC10208158 DOI: 10.7759/cureus.38065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/23/2023] [Indexed: 05/27/2023] Open
Abstract
Elevated basal serum tryptase (BST) levels are markers of both mast cell activation and overall mast cell burden. We present a family of four individuals with elevated tryptase levels greater than or equal to 20 mcg/L, all of whom exhibited signs and symptoms suggestive of mast cell activation. Differential diagnoses included hereditary alpha tryptasemia (HaT), systemic mastocytosis (SM), and mast cell activation syndrome (MCAS). In three individuals, SM was ruled out with normal morphology on bone marrow biopsy combined with negative genetic markers. Further workup would be required for the diagnosis of MCAS since serum tryptase levels were not obtained in our emergency department during acute episodes. Although genetic testing for HaT was not available upon initial workup, HaT remains the most likely explanation for this family's elevated BST.
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Affiliation(s)
| | | | | | - Stuart T Wood
- Infectious Disease, Keesler Medical Center, Biloxi, USA
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5
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Ritter S, Bowden J, Pattanaik D. A case of perioperative anaphylaxis presenting as hereditary alpha tryptasemia. Ann Allergy Asthma Immunol 2022; 129:13-16. [PMID: 35292365 DOI: 10.1016/j.anai.2022.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 03/07/2022] [Accepted: 03/08/2022] [Indexed: 10/18/2022]
Affiliation(s)
- Shaunah Ritter
- Division of Allergy and Immunology, Le Bonheur Children's Medical Center, The University of Tennessee Health Sciences Center, Memphis, Tennessee.
| | - Jarred Bowden
- Department of Pharmacy, VA Medical Center, Memphis, Tennessee
| | - Debendra Pattanaik
- Section of Allergy and Immunology, VA Medical Center, The University of Tennessee Health Sciences Center, Memphis, Tennessee
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6
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Thomas EG, Thomas DJ. Mimics of Allergy and Angioedema: Scombroid, Mast Cell Activation Disorders, and Hereditary Alpha Tryptasemia. Emerg Med Clin North Am 2021; 40:119-133. [PMID: 34782083 DOI: 10.1016/j.emc.2021.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Scombroid poisoning, systemic mastocytosis, and hereditary alpha tryptasemia all present with episodes that resemble allergic reactions. Knowledge regarding systemic mastocytosis and hereditary alpha tryptasemia is quickly evolving. Epidemiology, pathophysiology, and strategies to identify and diagnose are discussed. Evidence-based management in the emergency setting and beyond is also explored and summarized. Key differences are described between these events and allergic reactions.
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Affiliation(s)
- Elizabeth G Thomas
- Department of Emergency Medicine, Ochsner Medical Center, 1514 Jefferson Highway, Jefferson, New Orleans, LA 70121, USA.
| | - Daniel James Thomas
- Department of Emergency Medicine, Ochsner Medical Center, 1514 Jefferson Highway, Jefferson, New Orleans, LA 70121, USA
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7
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Bethea LH, Tuano KS, Seth N, Chinen J. Hereditary alpha tryptasemia in identical twins. Ann Allergy Asthma Immunol 2021; 127:503-504. [PMID: 34157394 DOI: 10.1016/j.anai.2021.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/06/2021] [Accepted: 06/16/2021] [Indexed: 11/16/2022]
Affiliation(s)
- Louise H Bethea
- Allergy, Asthma and Immunology Care Center, The Woodlands, Texas
| | - Karen S Tuano
- Section of Immunology, Allergy and Retrovirology, Department of Pediatrics, Baylor College of Medicine, Houston, Texas; Texas Children's Hospital, The Woodlands, Texas
| | - Neha Seth
- Section of Immunology, Allergy and Retrovirology, Department of Pediatrics, Baylor College of Medicine, Houston, Texas; Texas Children's Hospital, The Woodlands, Texas
| | - Javier Chinen
- Section of Immunology, Allergy and Retrovirology, Department of Pediatrics, Baylor College of Medicine, Houston, Texas; Texas Children's Hospital, The Woodlands, Texas.
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8
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Hereditary α tryptasemia is a valid genetic biomarker for severe mediator-related symptoms in mastocytosis. Blood 2021; 137:238-247. [PMID: 32777817 DOI: 10.1182/blood.2020006157] [Citation(s) in RCA: 106] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 07/28/2020] [Indexed: 12/19/2022] Open
Abstract
Mastocytosis is a hematopoietic neoplasm characterized by expansion of KIT D816V-mutated clonal mast cells in various organs and severe or even life-threatening anaphylactic reactions. Recently, hereditary α-tryptasemia (HαT) has been described as a common genetic trait with increased copy numbers of the α-tryptase encoding gene, TPSAB1, and associated with an increased basal serum tryptase level and a risk of mast cell activation. The purpose of our study was to elucidate the clinical relevance of HαT in patients with mastocytosis. TPSAB1 germline copy number variants were assessed by digital polymerase chain reaction in 180 mastocytosis patients, 180 sex-matched control subjects, 720 patients with other myeloid neoplasms, and 61 additional mastocytosis patients of an independent validation cohort. α-Tryptase encoding TPSAB1 copy number gains, compatible with HαT, were identified in 17.2% of mastocytosis patients and 4.4% of the control population (P < .001). Patients with HαT exhibited higher tryptase levels than patients without HαT (median tryptase in HαT+ cases: 49.6 ng/mL vs HαT- cases: 34.5 ng/mL, P = .004) independent of the mast cell burden. Hymenoptera venom hypersensitivity reactions and severe cardiovascular mediator-related symptoms/anaphylaxis were by far more frequently observed in mastocytosis patients with HαT than in those without HαT. Results were confirmed in an independent validation cohort. The high prevalence of HαT in mastocytosis hints at a potential pathogenic role of germline α-tryptase encoding TPSAB1 copy number gains in disease evolution. Together, our data suggest that HαT is a novel emerging robust biomarker in mastocytosis that is useful for determining the individual patient´s risk of developing severe anaphylaxis.
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Luskin KT, White AA, Lyons JJ. The Genetic Basis and Clinical Impact of Hereditary Alpha-Tryptasemia. THE JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY-IN PRACTICE 2021; 9:2235-2242. [PMID: 33744473 DOI: 10.1016/j.jaip.2021.03.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 02/21/2021] [Accepted: 03/09/2021] [Indexed: 12/11/2022]
Abstract
Hereditary alpha-tryptasemia (HαT) is an autosomal dominant genetic trait found in 4% to 6% of the general population and defined by excess copies of alpha-tryptase at TPSAB1. Elevated basal serum tryptase (sBT >8 ng/mL) is a defining feature of HαT and appears to result from increased pro-alpha-tryptase synthesis and secretion rather than mast cell activation. It is estimated that approximately one-third of individuals with HαT have associated symptoms, including cutaneous, gastrointestinal, atopic, musculoskeletal, autonomic, and neuropsychiatric manifestations. HαT is found at a disproportionately high rate in systemic mastocytosis and idiopathic anaphylaxis, and is a modifying factor that independently increases the incidence and severity of anaphylaxis. The varied phenotypes associated with HαT may, in part, result from coinheritance of other genetic variants, increased expression of α-/ß-tryptase heterotetramers, and/or overexpression of pro-alpha-tryptase, although further studies are needed. There is an accurate diagnostic test available to confirm HαT in patients that can be used in combination with sBT to help risk-stratify individuals in whom bone marrow biopsy is being considered. There is no specific treatment for symptoms associated with HαT, and management is focused on controlling clinical manifestations with mast cell mediator antagonists, aspirin, inhalers, epinephrine, omalizumab, and involvement of other specialists.
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Affiliation(s)
- Kathleen T Luskin
- Division of Allergy, Asthma and Immunology, Scripps Clinic, La Jolla, Calif.
| | - Andrew A White
- Division of Allergy, Asthma and Immunology, Scripps Clinic, La Jolla, Calif
| | - Jonathan J Lyons
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Md.
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Abstract
PURPOSE OF REVIEW This review describes improvement in diagnostic accuracy, prediction of outcomes, identifying high-risk factors, and refinements of treatment that continue to evolve over the past 5-10 years. RECENT FINDINGS The risk of anaphylaxis is relatively low (< 5%) in patients with previous large local reactions or strictly cutaneous systemic reactions, but much higher in those with moderate-to-severe anaphylaxis (40%-70%) or mastocytosis (> 90%). Use of recombinant venom allergens and basophil activation tests may improve diagnostic accuracy. Elevated serum tryptase (and possible mastocytosis) occurs in 10% of patients with insect sting allergy, and in 25% of those with hypotensive reactions. Rush VIT is proven safe and rapidly effective. There are known high-risk factors that justify treatment beyond 5 years. Diagnostic accuracy and prediction of risk have improved in recent years. There are still knowledge gaps related to prediction and management of risk with current diagnostic and therapeutic modalities.
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11
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Genetic Regulation of Tryptase Production and Clinical Impact: Hereditary Alpha Tryptasemia, Mastocytosis and Beyond. Int J Mol Sci 2021; 22:ijms22052458. [PMID: 33671092 PMCID: PMC7957558 DOI: 10.3390/ijms22052458] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/20/2021] [Accepted: 02/25/2021] [Indexed: 12/12/2022] Open
Abstract
Tryptase is a serine protease that is predominantly produced by tissue mast cells (MCs) and stored in secretory granules together with other pre-formed mediators. MC activation, degranulation and mediator release contribute to various immunological processes, but also to several specific diseases, such as IgE-dependent allergies and clonal MC disorders. Biologically active tryptase tetramers primarily derive from the two genes TPSB2 (encoding β-tryptase) and TPSAB1 (encoding either α- or β-tryptase). Based on the most common gene copy numbers, three genotypes, 0α:4β, 1α:3β and 2α:2β, were defined as “canonical”. About 4–6% of the general population carry germline TPSAB1-α copy number gains (2α:3β, 3α:2β or more α-extra-copies), resulting in elevated basal serum tryptase levels. This condition has recently been termed hereditary alpha tryptasemia (HαT). Although many carriers of HαT appear to be asymptomatic, a number of more or less specific symptoms have been associated with HαT. Recent studies have revealed a significantly higher HαT prevalence in patients with systemic mastocytosis (SM) and an association with concomitant severe Hymenoptera venom-induced anaphylaxis. Moreover, HαT seems to be more common in idiopathic anaphylaxis and MC activation syndromes (MCAS). Therefore, TPSAB1 genotyping should be included in the diagnostic algorithm in patients with symptomatic SM, severe anaphylaxis or MCAS.
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Zama D, Muratore E, Giannetti A, Neri I, Conti F, Magini P, Ferrari S, Pession A. Case Report: Hereditary Alpha Tryptasemia in Children: A Pediatric Case Series and a Brief Overview of Literature. Front Pediatr 2021; 9:716786. [PMID: 34490168 PMCID: PMC8417938 DOI: 10.3389/fped.2021.716786] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 08/02/2021] [Indexed: 12/12/2022] Open
Abstract
Hereditary alpha tryptasemia (HαT) is a recently described autosomal dominant genetic trait caused by an increased copy number of the TPSAB1 gene. It commonly leads to elevated basal serum tryptase levels, and it is associated with heterogeneous clinical manifestations. Some individuals report few to no symptoms, while others present with a spectrum of debilitating features. Most symptoms related to HαT may be explained by mast cell activation and mediator release, namely multiple allergies, anaphylaxis, and skin rash. However, the genotype-phenotype correlation has not yet been clearly understood. In particular, the characterization of the clinical spectrum lacks in children, where differential diagnosis could be challenging. Systemic mastocytosis, HαT, and mast cell activation syndrome are all associated with overlapping pathophysiology and symptoms, making the distinction between these conditions a difficult task. We herein describe two pediatric cases of HαT and their respective families at our tertiary care teaching hospital, highlighting the diagnostic workup and differential diagnosis. We also provide a brief review of the literature to underline the peculiar features of this condition in children.
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Affiliation(s)
- Daniele Zama
- Pediatric Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Edoardo Muratore
- Pediatric Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Arianna Giannetti
- Pediatric Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Iria Neri
- Dermatology Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Francesca Conti
- Pediatric Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Pamela Magini
- Unità Genetica Medica, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Simona Ferrari
- Unità Genetica Medica, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Andrea Pession
- Pediatric Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
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Valent P, Akin C, Nedoszytko B, Bonadonna P, Hartmann K, Niedoszytko M, Brockow K, Siebenhaar F, Triggiani M, Arock M, Romantowski J, Górska A, Schwartz LB, Metcalfe DD. Diagnosis, Classification and Management of Mast Cell Activation Syndromes (MCAS) in the Era of Personalized Medicine. Int J Mol Sci 2020; 21:ijms21239030. [PMID: 33261124 PMCID: PMC7731385 DOI: 10.3390/ijms21239030] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/16/2020] [Accepted: 11/24/2020] [Indexed: 12/12/2022] Open
Abstract
Mast cell activation (MCA) is seen in a variety of clinical contexts and pathologies, including IgE-dependent allergic inflammation, other immunologic and inflammatory reactions, primary mast cell (MC) disorders, and hereditary alpha tryptasemia (HAT). MCA-related symptoms range from mild to severe to life-threatening. The severity of MCA-related symptoms depends on a number of factors, including genetic predisposition, the number and releasability of MCs, organs affected, and the type and consequences of comorbid conditions. In severe systemic reactions, MCA is demonstrable by a substantial increase of basal serum tryptase levels above the individual’s baseline. When, in addition, the symptoms are recurrent, involve more than one organ system, and are responsive to therapy with MC-stabilizing or mediator-targeting drugs, the consensus criteria for the diagnosis of MCA syndrome (MCAS) are met. Based on the etiology of MCA, patients can further be classified as having i) primary MCAS where KIT-mutated, clonal, MCs are detected; ii) secondary MCAS where an underlying IgE-dependent allergy or other reactive MCA-triggering pathology is found; or iii) idiopathic MCAS, where neither a triggering reactive state nor KIT-mutated MCs are identified. Most severe MCA events occur in combined forms of MCAS, where KIT-mutated MCs, IgE-dependent allergies and sometimes HAT are detected. These patients may suffer from life-threatening anaphylaxis and are candidates for combined treatment with various types of drugs, including IgE-blocking antibodies, anti-mediator-type drugs and MC-targeting therapy. In conclusion, detailed knowledge about the etiology, underlying pathologies and co-morbidities is important to establish the diagnosis and develop an optimal management plan for MCAS, following the principles of personalized medicine.
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Affiliation(s)
- Peter Valent
- Department of Internal Medicine I, Division of Hematology and Hemostaseology and Ludwig Boltzmann Institute for Hematology and Oncology, Medical University of Vienna, 1090 Vienna, Austria
- Correspondence: (P.V.); (B.N.)
| | - Cem Akin
- Division of Allergy and Clinical Immunology, University of Michigan, Ann Arbor, MI 48106, USA;
| | - Boguslaw Nedoszytko
- Department of Dermatology, Medical University of Gdansk, 80-211 Gdansk, Poland
- Correspondence: (P.V.); (B.N.)
| | | | - Karin Hartmann
- Division of Allergy, University Hospital Basel and University of Basel, 4031 Basel, Switzerland;
| | - Marek Niedoszytko
- Department of Allergology, Medical University of Gdansk, 80-211 Gdansk, Poland; (M.N.); (J.R.); (A.G.)
| | - Knut Brockow
- Department of Dermatology and Allergy Biederstein, Technical University of Munich, D-80802 Munich, Germany;
| | - Frank Siebenhaar
- Dermatological Allergology, Department of Dermatology and Allergy, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany;
| | - Massimo Triggiani
- Division of Allergy and Clinical Immunology, University of Salerno, 84131 Salerno, Italy;
| | - Michel Arock
- Department of Hematological Biology, Pitié-Salpêtrière Hospital, Pierre et Marie Curie University (UPMC), 75005 Paris, France;
| | - Jan Romantowski
- Department of Allergology, Medical University of Gdansk, 80-211 Gdansk, Poland; (M.N.); (J.R.); (A.G.)
| | - Aleksandra Górska
- Department of Allergology, Medical University of Gdansk, 80-211 Gdansk, Poland; (M.N.); (J.R.); (A.G.)
| | - Lawrence B. Schwartz
- Department of Internal Medicine, Division of Rheumatology, Allergy & Immunology, Virginia Commonwealth University, Richmond, VA 23284, USA;
| | - Dean D. Metcalfe
- Laboratory of Allergic Diseases, NIAID, NIH, Bethesda, MD 20852, USA;
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Lobbes H, Reynaud Q, Mainbourg S, Lega JC, Durieu I, Durupt S. [Tryptase: A practical guide for the physician]. Rev Med Interne 2020; 41:748-755. [PMID: 32712042 DOI: 10.1016/j.revmed.2020.06.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/24/2020] [Accepted: 06/07/2020] [Indexed: 12/19/2022]
Abstract
Tryptase is the most abundant endopeptidase released by mast cells degranulation, involved in many pro and anti-inflammatory processes. Normal serum tryptase range is 0-11.4 μg/L. Tryptase is a useful diagnostic tool for anaphylaxis, systemic mastocytosis (SM) and mast cell activation syndrome (MCAS), where specific threshold values must be used. SM diagnosis criteria include evidence of dense mast cell infiltrate either in the bone marrow or the affected organ (such as skin), presence of KIT D816V mutation and elevated serum tryptase level (>20 μg/L). In SM, tryptase level is correlated with the burden of mast cells in bone marrow. MCAS should be considered in case of severe and recurrent typical clinical signs of systemic mast cell activation involving at least two organs, associated with an increase in serum tryptase level of 20% + 2 μg/L from the individual's baseline. Anaphylaxis is the most severe among hypersensitivity reactions. A clonal mast cell disorder is a central question in anaphylaxis and appropriate explorations should be conducted in these patients. Triggers for anaphylactic reactions vary significantly in the general population and in patients with MS or MCAS. Finally, physicians must be aware of the many pathological and physiological situations that affect tryptase levels.
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Affiliation(s)
- H Lobbes
- Service de Médecine Interne, Hôpital Estaing, CHU de Clermont-Ferrand, 1 Place Lucie et Raymond Aubrac, 63000 Clermont-Ferrand, France; Service de Médecine Interne et Vasculaire, Hôpital Lyon Sud, Hospices Civils de Lyon, 165 Chemin du grand Revoyet, 69310 Pierre-Bénite, France.
| | - Q Reynaud
- Service de Médecine Interne et Vasculaire, Hôpital Lyon Sud, Hospices Civils de Lyon, 165 Chemin du grand Revoyet, 69310 Pierre-Bénite, France
| | - S Mainbourg
- Service de Médecine Interne et Vasculaire, Hôpital Lyon Sud, Hospices Civils de Lyon, 165 Chemin du grand Revoyet, 69310 Pierre-Bénite, France
| | - J C Lega
- Service de Médecine Interne et Vasculaire, Hôpital Lyon Sud, Hospices Civils de Lyon, 165 Chemin du grand Revoyet, 69310 Pierre-Bénite, France
| | - I Durieu
- Service de Médecine Interne et Vasculaire, Hôpital Lyon Sud, Hospices Civils de Lyon, 165 Chemin du grand Revoyet, 69310 Pierre-Bénite, France
| | - S Durupt
- Service de Médecine Interne et Vasculaire, Hôpital Lyon Sud, Hospices Civils de Lyon, 165 Chemin du grand Revoyet, 69310 Pierre-Bénite, France
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