Elevated Tryptase Levels Research Articles

Fatal anaphylaxis due to peanut exposure from oral intercourse

BackgroundIntimacy-related allergic reactions, including anaphylaxis, are under-reported due to social stigma, lack of awareness, and misdiagnosis. The differential diagnosis for intimacy-related anaphylaxis is extensive and includes systemic human seminal plasma allergy, exercise-induced anaphylaxis, asthma exacerbation, latex allergy, and transference of food or drug allergens through saliva or seminal fluid.Case presentationTwo adolescents met on a popular dating phone application. One individual had a long-standing history of asthma and peanut allergy. Although they never kissed, the male with peanut allergy received fellatio, while the other male had eaten peanut butter before they met. During fellatio, the peanut allergic male developed respiratory symptoms, used his bronchodilator, and collapsed. He remained unconscious despite aggressive interventions by emergency personnel called to the site. The clinical history and autopsy results suggested anaphylaxis to peanut allergen exposure from the intimate exposure as the cause of death.Discussion and conclusionsTo date, nearly all reported cases of intimacy-related anaphylaxis involve symptomatic women. This is the first report of intimacy-related anaphylaxis involving men who have sex with men and the first report of potential allergen transfer from oral mucosa to a patient receiving fellatio. Based on the paucity of published cases, death from intimacy-related anaphylaxis is exceedingly rare. Post-mortem analysis is inherently difficult, as an elevated tryptase level has myriad potential causes; nevertheless, the authors suggest that intimacy-related anaphylaxis due to peanut allergy is the most likely diagnosis. With increasing popularity of relationship applications, especially amongst stigmatized populations, this case highlights the importance of allergy awareness and patient education to decrease risk, particularly in the adolescent population, who are already at increased risk of severe anaphylaxis. Especially amongst those participating in intimate activities, disclosure of one’s allergies warrants discussion, as the outcome can be fatal. Our case demonstrates the crucial need for increased advocacy in food allergy, education around intimacy-related anaphylaxis, and the importance of allergy awareness and prevention across all populations.

Routine KIT p.D816V screening identifies clonal mast cell disease in patients with Hymenoptera allergy regularly missed using baseline tryptase levels alone

Clonal mast cell disorders and elevated basalserum tryptase (BST) levels with unknown cause(s)are associated with severe Hymenoptera venom-triggered anaphylaxis (HVA). However, some individuals with clonal disease have a normal BST level (<11.4 ng/mL). Our aim was to evaluate whether screening for KIT p.D816V in the blood is a useful clinical tool to risk-stratify patients with venom allergy. We prospectively recruited 374 patients with Hymenoptera allergy and no overt signs of mastocytosis who were referred to our center during the years 2018 and 2019. KIT p.D816V was determined in their peripheral blood by quantitative PCR, and tryptase genotyping was performed by droplet digital PCR. In all, 351 patients (93.9%) had normal levels of BST, and KIT p.D816V was detected in 8% of patients (28 of 351), predominantly in patients with the most severe Mueller grade IV anaphylaxis (18.2% [24 of 132] vs 1.8% in patients with lower grades [4 of 88 with grade III and 0 of 131 with other grades]; P< .001). In grade IV patients with a normal BST level, KIT p.D816V was associated with more severe symptoms, including a significantly higher frequency of loss of consciousness (58.3% [14 of 24] vs 34.3% [37 of 108]; P= .03) and absence of skin symptoms (41.7% [10 of 24] vs 15.7% [17 of 108]; P= .004). Among patients with a normal BST level, KIT p.D816V (OR= 10.25 [95% CI= 3.75-36.14]; P< .0001) was the major risk factor associated with severe HVA. Hereditary α-tryptasemia (HαT) due to increased germline copies of TPSAB1 encoding α-tryptase was the most common cause (65.2% [15 of 23]) of elevated BST level in patients with HVA, and together with KIT p.D816V, it accounted for 90% of BST level elevations (20 of 23) in patients with HVA. These results indicate that routine KIT p.D816V screening identifies clonal disease in high-risk patients withHVA who are regularly missed when BST level is used alone.

Perioperative Allergic Reactions: Allergy Assessment and Subsequent Anesthesia

Evidence-based guidelines are needed in the United States to improve evaluation of perioperative allergic reactions including recommendations for subsequent anesthesia. To identify causative agent(s) and evaluate patients' tolerability of subsequent anesthesia in patients evaluated by Allergy/Immunology (A/I) at Massachusetts General Hospital. We performed a retrospective review of patients referred to the outpatient A/I clinic for perioperative allergic reactions between October 2003 and May 2017. Patient demographics, atopic history, and prior adverse drug reactions were reviewed. Patients underwent a comprehensive evaluation with testing including skin testing (ST), drug challenges (when appropriate), tryptase level measurement, and specific IgE to latex measurement. Tolerance of subsequent procedures requiring anesthesia was assessed. Of 123 patients referred, 74 (60%) were female and the mean age was 46 (±18) years. At least 1 causative agent was identified in 28 patients (24%, n= 28 of 118). Seventeen of 28 (61%) patients were ST positive to an antibiotic, including 13 (46%) positive to cefazolin; 3 patients (11%) had a positive latex specific IgE. Of 85 patients who had subsequent anesthesia with a known outcome, 78 (91%) did not have another perioperative allergic reaction. Two of 5 patients with an elevated baseline tryptase level did not tolerate subsequent anesthesia. The majority of patients safely received subsequent anesthesia after comprehensive A/I evaluation for their perioperative allergic reactions; however, improved algorithmic care is needed in the United States. Among ST-positive patients (24%), antibiotics (especially cefazolin) were the most common culprits. An elevated baseline tryptase level was associated with an increased risk of recurrent perioperative allergic reactions.

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

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

Pediatric mastocytosis.

The current article highlights recent developments in the field of pediatric cutaneous mastocytosis. Mastocytosis is a spectrum of conditions that range from fleetingly benign to aggressively malignant. Through recognizing the natural progression of disease, the role of biomarkers and mutational analysis, treatment and risk of triggers, physicians can confidently stage, counsel and manage patients with pediatric cutaneous mastocytosis. Many lesions of cutaneous mastocytosis are chronic with some resolving around the mid-teenage years. KIT mutations are found in the majority of pediatric cutaneous mastocytosis but are not correlated with prognosis. Serum tryptase levels may be elevated in pediatric cutaneous mastocytosis patients without systemic mastocytosis. Pimecrolimus, omalizumab and tyrosine kinase inhibitors are effective treatment options. The low risk of NSAIDs and vaccinations has been characterized and epinephrine autoinjectors are rarely utilized in the pediatric cutaneous mastocytosis patient. Pediatric cutaneous mastocytosis is a heterogeneous disease with good outcome overall. Organomegaly, elevated tryptase levels and the presence of KIT mutation in peripheral blood may aid in the decision to pursue bone marrow biopsy. The armamentarium of treatments has expanded and better understanding of the significance of triggers and vaccination safety allows the clinician to thoughtfully counsel and allay anxiety around pediatric cutaneous mastocytosis.

Serum tryptase levels in pediatric mastocytosis and association with systemic symptoms

Mastocytosis is characterized by clonal expansion of mast cells. When diagnosed in children, mastocytosis is usually limited to the skin, which is termed cutaneous mastocytosis (CM). According to its clinical presentation, CM can be classified into mastocytoma (20% of cases), maculopapular CM (MPCM, 75%; previously urticaria pigmentosa), and diffuse cutaneous mastocytosis (DCM; 5%). 1 Hartmann K. Escribano L. Grattan C. et al. Cutaneous manifestations in patients with mastocytosis: consensus report of the European Competence Network on Mastocytosis; the American Academy of Allergology, Asthma & Immunology; and the European Academy of Allergology and Clinical Immunology. J Allergy Clin Immunol. 2016; 137: 35-45 Abstract Full Text Full Text PDF PubMed Scopus (176) Google Scholar ,2 Méni C. Bruneau J. Georgin-Lavialle S. et al. Paediatric mastocytosis: a systematic review of 1747 cases. Br J Dermatol. 2015; 172: 642-651 Crossref PubMed Scopus (104) Google Scholar Contrary to adult-onset mastocytosis, complete or partial resolution is often noted by adolescence. 3 Carter M.C. Clayton S.T. Komarow H.D. et al. Assessment of clinical findings, tryptase levels, and bone marrow histopathology in the management of pediatric mastocytosis. J Allergy Clin Immunol. 2015; 136: 1673-1679 Abstract Full Text Full Text PDF PubMed Scopus (52) Google Scholar Serum tryptase level is a marker of mast cell burden. It is widely available and used to assess risk of systemic involvement. Other causes of elevated basal tryptase levels include chronic eosinophilic leukemia, renal disease, and hereditary α-tryptasemia. 4 Butterfield J.H. Ravi A. Pondee T. Mast cell mediators and significance in clinical practice in mastocytosis. Immunol Allergy Clin N Am. 2018; 38: 397-410 Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar

Sugammadex and Hypersensitivity-Related Reactions: a Review

The purpose of this review is to identify and understand the incidence and implications of sugammadex-induced hypersensitivity and anaphylaxis. This review also focuses on the mechanistic causation of anaphylaxis with regard to sugammadex administration and the management of anaphylaxis. The overall incidence of sugammadex-induced anaphylaxis is low, approximately 1:3500, and is comparable with other medications commonly used during the intraoperative period. Several studies and case reports have demonstrated that the mechanism of anaphylaxis is likely IgE- or basophil-mediated and that a diagnosis of anaphylaxis to confirm the etiology of urticaria, hypotension, bronchospasm, and other symptoms is based on positive skin prick testing, elevated tryptase levels, and dose-dependent activation of basophils during in vitro analysis. Bradycardia is a poorly understood adverse effect of sugammadex; however, the risk of bradycardia does not appear to be increased when compared with neostigmine. Sugammadex-induced anaphylaxis is a relatively rare complication but carries a risk of morbidity and mortality if inadequately identified and treated. Existing severity scales allow anesthesiologists to stratify the severity of an anaphylactic response and provide appropriate intraoperative treatment.

Utility of major basic protein, eotaxin-3, and mast cell tryptase staining for prediction of response to topical steroid treatment in eosinophilic esophagitis: analysis of a randomized, double-blind, double dummy clinical trial.

Inflammatory factors in eosinophilic esophagitis (EoE), including major basic protein (MBP), eotaxin-3 (EOT3) and mast cell tryptase (TRP), may predict treatment response to topical corticosteroids (tCS). We aimed to determine whether baseline levels of these markers predict response to tCS for EoE. To do this, we analyzed data from a randomized trial comparing two topical steroids for treatment of newly diagnosed EoE (NCT02019758). A pretreatment esophageal biopsy was stained for MBP, EOT3, and TRP to quantify tissue biomarker levels (cells/mm2). Levels were compared between histologic responders (<15 eos/hpf) and nonresponders (the primary outcome), and endoscopic responders (EREFS<2) and nonresponders. Complete histologic response (<1 eos/hpf) was also assessed, and area under the receiver operator characteristic curve (AUC) was calculated. We also evaluated whether baseline staining predicted symptom relapse in the trial's off-treatment observation phase. Baseline samples were evaluable in 110/111 subjects who completed the randomized trial. MBP levels were higher in nonresponders (n = 36) than responders (704 vs. 373 cells/mm2; P = 0.007), but EOT3 and TRP levels were not statistically different. The combination of all three stains had an AUC of 0.66 to predict response. For complete histologic response, baseline TRP levels were higher in nonresponders (n = 69) than responders (370 vs. 268 mast cells/mm2; P = 0.01), with an AUC of 0.65. The AUC for endoscopic response was 0.68. Baseline staining did not predict symptom recurrence after remission. Pretreatment MBP, EOT3, and TRP levels were not strongly or consistently associated with histologic or endoscopic response to topical steroids. While elevated TRP levels may be associated with nonresponse compared with complete response, the magnitude and predictive utilities were modest. Novel methods for predicting steroid response are still required.

Mastocytosis onset in a patient with treated hairy cell leukemia: Just a coincidence?

Mastocytosis is a mast cell disease caused by functionally defective infiltrating mast cells and CD34+ mast cell precursors. The heterogeneous group of mast cell disorders is categorized into five variants in the updated 2017 World Health Organization (WHO) classification among those systemic mastocytosis with an associated neoplasm (SM-AHN). Except for myeloid neoplasia, lymphoproliferative disorders associated to SM-AHN are more scarce.Here, we report the second case ever described of associated mastocytosis and hairy-cell disease. A 38-year-old female patient without any specific medical history was diagnosed a hairy cell leukemia and BRAFV600E mutation was found in hairy cells. Since purine-analogs were avoided to prevent prolonged myelosuppression, she was treated with vemurafenib and rituximab. Despite early discontinuation due to vemurafenib-induced agranulocytosis, a partial response was observed. Strikingly, bone marrow biopsy performed one month after vemurafenib discontinuation revealed a nodular infiltration by 30% tumoral mastocytes. Along with elevated tryptase level, KITD816V mutation on mastocytes and clinical exam, the patient was diagnosed with systemic mastocytosis with an associated hematological neoplasm (SM-AHN). No BRAFV600E mutation was found on mastocytes.The physiopathology of this association is not known and might be only a coincidence or a common genetic driver mutation enhancing mast and hairy cells.

Tryptase values in anaphylaxis and insect allergy.

To recognize the relevance of serum tryptase measurement as a useful tool for the diagnosis of allergic diseases and mast cell disorders. Recent data on the role of mast cells and tryptase in allergic and other diseases provide new understanding into the mechanisms and causes of anaphylaxis. Measurement of transiently elevated tryptase levels shortly after a severe reaction can help elucidate mechanism behind the reaction in identifying mast cell activation. Hymenoptera venom allergy represents an important cause of morbidity and mortality worldwide. Venom allergy is a typical IgE-mediated reaction because of sensitization to one or more allergens of the venom, and accounts for 1.5-34% of all cases of anaphylaxis. There is a preferential association between insect venom allergy and mastocytosis. The diagnosis of a clonal mast cell disease leads to therapeutic consequences concerning the treatment of venom allergy. In conclusion, baseline tryptase levels support the clinical diagnosis of anaphylaxis and mast cell disorders, determine venom immunotherapy treatment and are relevant in deciding on lifelong treatment.

MON-508 Misdiagnosed Bone Metastasis: A Rare Case of Polyostotic Bone Lesions

Background The most common cause of diffuse bone lesions in adults is metastatic disease. We present a case of a rare cause of polyostotic bone disease associated with low bone mineral density in a postmenopausal woman. Case description 53-year-old female presented with back pain. She had no significant past medical history besides a chronic rash on her back and chest that was triggered by direct sunlight. She denied flushing, diarrhea or syncope. On exam, she had tenderness in the lumbar spine and dermatographism. Plain radiographs revealed multiple sclerotic lesions in the ribs, lumbar spine and pelvis, and notably a 2.5cm lesion at L5 vertebral body concerning for metastatic disease. Her blood cell counts, liver enzymes, glomerular filtration rate, lactate dehydrogenase, alkaline phosphatase, PTH intact, Phosphorus, Calcium and vitamin D were within normal limits. Serum and urine protein electrophoresis did not show monoclonal gammopathy. Serum tryptase level was elevated at 57 ng/mL (<11ng/mL). Bone marrow biopsy revealed multiple aggregates of atypical spindled mast cells that showed aberrant expression of CD25. KIT point mutation at codon 816 was identified. Systemic Mastocytosis (SM) was diagnosed. This was considered indolent variant due to lack of organopathy or dysmyelopoiesis. Initiation of histamine receptor blockers led to improvement of symptoms. Initial bone density scan interpretation was challenging due to mastocyte infiltration in regions of interest. The only regions not affected were L1 and the left femoral neck. Osteoporosis was diagnosed due to a T-score under -2.5 at these sites. The patient was less than one year post-menopause and likely at the peak of her bone loss. She was started on alendronate. Discussion The skeleton is one of the most frequent sites of involvement in SM. Patients can present with diffuse bone pain or pathologic fractures leading to imaging studies that reveal both osteolytic and osteosclerotic lesions. Widespread metastatic disease may be initially misdiagnosed, such as in our patient, leading to medical errors. SM can be identified by an elevated tryptase level and confirmed with bone marrow biopsy. Mast cells can exert a direct stimulatory effect on osteoblast and osteoclasts. The predominance of either process would direct bone involvement towards bone sclerosis or bone loss. There is a high prevalence of fractures and osteoporosis in SM. Available studies identify osteoporosis prevalence around 18-37%. Whether patients with focal or diffuse osteosclerosis have more or less osteoporosis or risk of fractures has not been determined due to absence of large longitudinal studies. DXA diagnosis of osteoporosis may be inaccurate due to patchy distribution of mastocyte cell infiltrates or presence of fractures. Small studies on the effect of bisphosphonates have been published with evidence of greater BMD gain with zoledronic acid.

Inflammatory reaction patterns of the lung as a response to alveolar hypoxia and their significance for the diagnosis of asphyxiation

Providing evidence of asphyxia death is a challenging issue in forensic pathology. Besides helpful macroscopical signs (e.g. strangulation mark, lung edema), recent data from literature indicate that the time of protracted asphyxia suffices to trigger an increase of giant cells and a migration of inflammatory cells from the bone marrow to the lung, thus offering a help in diagnosis of asphyxia death. In search of new valid asphyxia markers, the present study examined this hypothesis and investigated the leading role of pre-existing lung tissue cells and their functional state in reaction patterns to asphyxia. In specimens of suffocated human lungs following a short (n = 13) and a long asphyxia terminal episode (n = 15), and controls (sudden cardiovascular (n = 11) and traumatic deaths (n = 7)), the count of alveolar phagocytes, megakaryocytes, giant and mast cells, using H&E and toluidine blue staining, was performed. To show macrophage activation, immunohistochemical stainings for CD68, late (25F9) and early (MRP-8/-14) stage inflammatory markers were used. Measuring concentration of tryptase in femoral blood acted as a parameter for mast cell degranulation and consequently their activation. Results showed the lack of specificity of macroscopical parameters despite an association of suffocation with heavy lung edema. No significant differences in the numbers of inflammatory cells in the lungs of different case groups were detected. The doubling of MRP-8- and a five-fold elevation of MRP-14-positive cells compared to cardiovascular controls, proved an early activation state of pre-exiting monocytes in protracted asphyxia. These activated monocytes induced the degranulation of mast cells, resulting in slightly elevated tryptase levels in suffocation compared to cardiovascular controls. In summary, the duration of asphyxia (max. 20 min in cases investigated) only suffices to cause changes on molecular level, being not detectable in any specific macroscopical or histological form in the lung. Despite a potential utility of this molecular insight in individual cases, these results point to the classic doctrine of the evaluation of a rounded overall picture, accentuating on the proof of the ligature tool and the marks of suffocation process.

Elevated Tryptase in EoE Is an Independent Phenomenon Associated with Extra-Esophageal Symptoms.

Eosinophilic esophagitis (EoE) is a chronic disease characterized histologically by > 15 eosinophilsper high-power field (eos/hpf). Esophageal mucosal mast cells have been implicated in EoE pathogenesis. The association of atopy with EoE has been established but has not been correlated with levels of serum tryptase. The lack of concurrent atopy in some patients suggests the possibility that atopy may either be the related subtype of EoE or may be a sign of comorbidities. No study has looked at whether patients present with different phenotypes/comorbid disease when they have evidence of elevated serum tryptase. We hypothesized that these patients differ with respect to presentation and comorbidities with more refractory GI disease. To examine whether elevations of serum tryptase associate with different, more severe clinical presentations in EoE patients which may be explained via mast cell activation. Retrospective chart review identified 72 patients with EoE with results for serum tryptase between 2015 and 2016. Patients were classified as TryptaseHI (tryptase > 10.9µg/l) and TryptaseLO (< 10.9µg/l). Clinical characteristics and treatment response were compared using univariate analysis and multivariate regression between the groups. Out of 72 patients, 12 were tested as TryptaseHI (16.7%, 95% CI 8.1-25.3%). TryptaseHI was associated frequently with asthma (P = 0.0003), urticaria (P = 0.002), arthralgia (P = 0.005), sinusitis (P = 0.03), nausea/vomiting (P = 0.046), and eosinophilic gastrointestinal disease (P = 0.001). Asthma and arthralgia were found to be significantly associated with TryptaseHI (P = 0.0013, P = 0.0098, respectively). Mucosal eosinophil counts and tryptase levels were not correlated (R2 0.095, P = 0.77). Tryptase did not resolve with resolution of esophageal eosinophilia. We found that EoE patients with elevated tryptase levels more commonly presented with asthma, urticaria, arthralgia, nausea/vomiting, sinusitis, and more distal eosinophilia. This indicates that atopy in EoE patients warrants further exploration. The lack of correlation between histologic remission and reduction of serum tryptase levels post-treatment suggests that mast cell activation may be an independent, yet associated disease. More study into this unique association is warranted.

Harlequin syndrome in a subject with multinodular goiter and an elevated tryptase levels

Harlequin syndrome in a subject with multinodular goiter and an elevated tryptase levels

Mast cells and cancer.

Mast cells (MCs) are a potent proangiogenic factor in tumors, they product several pro-angiogenic factors such as fibroblast growth factor 2 (FGF-2), vascular epithelial growth factor (VEGF), tryptase and chymase. Tryptase is a serine protease classified as α-tryptase and β-tryptase, both produced by MCs. Tryptase degrades the tissues, playing an important role in angiogenesis and in the development of metastases. Serum tryptase increases with age, with increased damage to cells and risk of developing a malignancy and it could be considered the expression of a fundamental role of MCs in tumor growth or, on the contrary, in the antitumor response. Many biomarkers have been developed in clinical practice for improving diagnosis and prognosis of some neoplasms. Elevated tryptase levels are found in subgroups of patients with haematologic and solid cancers. In the current review, we want to update the perspectives of tryptase as a potential biomarker in daily practice in different neoplasms.

Highly sensitive assays are mandatory for the differential diagnosis of patients presenting with symptoms of mast cell activation: diagnostic work-up of 38 patients

Mastocytosis is a heterogeneous disease caused by excessive mast cell (MC) proliferation. Diagnosis of systemic mastocytosis (SM) is based on the presence of major and minor criteria defined by the World Health Organization. Symptoms of MC activation can also occur in patients without SM or without allergic or inflammatory disease. These MC activation syndromes (MCAS) can be divided into primary (monoclonal) MCAS (MMAS) vs. secondary and idiopathic MCAS. In this single center study, the diagnostic work-up of 38 patients with a clinical suspicion of SM and/or with elevated basic tryptase levels is presented. Clinical symptoms, biochemical parameters, results of bone marrow investigation, flow cytometric immunophenotyping, and molecular analysis were retrospectively reviewed. Twenty-three patients were found to have a monoclonal MC disorder of which 19 were diagnosed with SM and 4 with MMAS. In 13/19 SM patients, multifocal MC infiltrates in the bone marrow were found (major criterion), while in 6 the diagnosis was based on the presence of ≥3 minor criteria. Flow cytometric analysis of bone marrow showed CD25 expression of MCs in all patients with SM and MMAS (range: 0.002–0.3% of cells). In bone marrow, the KIT D816V mutation was detected in all SM patients but in only 2 patients with MMAS (range: 0.007–9% mutated cells). Basic tryptase elevation was demonstrated in 16/19 patients with SM but also in 9/19 patients without SM. Our study reveals the heterogeneity of primary MC disorders and the importance of sensitive assays in patients suspected of having SM.

Hymenoptera stings in the head region induce impressive, but not severe sting reactions.

Stings in the head region are considered to be a risk factor for severe systemic reactions to hymenoptera stings. We supposed that stings in skin areas, which are well supplied with blood, lead to more severe reactions and tested our hypothesis in 847 patients with confirmed hymenoptera venom allergy. However, symptom severity was independent from sting site: only 16.3% of patients with severe reactions were stung on the head (P = 0.017). But we confirmed age > 40 years (P < 0.001) as well as elevated basal tryptase levels (P = 0.001) as risk factors. Taking antihypertensive drugs seemed to have an influence: 41.7% of patients taking antihypertensive drugs experienced a severe reaction compared to 29.5% of patients, not taking such drugs (P = 0.019). However, considering patients' age in regression analysis, taking antihypertensive drugs had no effect on symptom severity (P = 0.342). Importantly, in most patients with severe reactions, cutaneous signs were absent (P < 0.001).

Added sensitivity of component-resolved diagnosis in hymenoptera venom-allergic patients with elevated serum tryptase and/or mastocytosis.

Anaphylaxis caused by hymenoptera venom allergy is associated with elevation of baseline serum tryptase (sBT) and/or mastocytosis in about 5% of patients. Up to now, no information has become available on single venom allergen sIgE reactivity and the usefulness of component-resolved approaches to diagnose this high-risk patient group. To address the component-resolved sIgE sensitization pattern and diagnostic sensitivity in hymenoptera venom-allergic patients with elevated sBT levels and/or mastocytosis, a panel of yellow jacket and honeybee venom allergens was applied on a widely used IgE immunoassay platform. Fifty-three patients with mastocytosis and/or elevated sBT tryptase level and systemic reactions to hymenoptera venoms were analyzed for their IgE reactivity to recombinant yellow jacket and honeybee venom allergens by Immulite3 g. sIgE reactivity to Ves v 1, Ves v 5, Api m 1 to Api m 4 and Api m 10 was found at a similar frequency in hymenoptera venom-allergic patients with and without elevated sBT levels and/or mastocytosis. However, the use of the recombinant allergens and a diagnostic cutoff of 0.1 kUA /L allowed the diagnosis of patients with otherwise undetectable IgE to venom extract. The diagnostic sensitivity of yellow jacket venom allergy using the combination of Ves v 1 and Ves v 5 was 100%. In high-risk patients with elevated sBT levels and/or mastocytosis, the use of molecular components and decreasing the threshold sIgE level to 0.1 kUA /L may be needed to avoid otherwise undetectable IgE to hymenoptera venom extracts in about 8% of such patients.

Hymenoptera Venom-Induced Anaphylaxis in Acute Care Settings

Anaphylaxis is a severe, potentially life-threatening allergic reaction. Venom-induced anaphylaxis can be especially dangerous, and patients are typically seen in acute care settings when systemic reactions occur. Elevated tryptase levels can be used to support the diagnosis of anaphylaxis when obtained within a few hours of symptom onset. For patients with venom allergy, immunotherapy significantly decreases the risk of recurrent systemic reactions. Studies examining physician recognition and management of anaphylaxis due to hymenoptera venom are underrepresented in the primary literature. An electronic case-based survey describing a child experiencing venom-induced anaphylaxis was completed by physicians in acute care settings. There were 45 total participants, with backgrounds in emergency medicine, urgent care, and primary care. 20% (9/45 physicians) elected not to treat with epinephrine and 24.4% (11/45) did not refer the child to an allergist. Of the 36 physicians (80%) who treated with epinephrine, 13.9% (5/36) responded that the patient was either not experiencing anaphylaxis or they were unsure. Less than 1% of physicians (3/45) elected to obtain a tryptase level. While 75.6% (34/45) of responders referred the patient to allergy, 57.8% (26/45) did not know the patient should start venom immunotherapy despite positive testing confirming hymenoptera allergy. There is a need for additional education regarding recognition and treatment of anaphylaxis induced by hymenoptera venom, which can be particularly life-threatening. Moreover, increased awareness of the utility of tryptase levels in the acute setting and the indications for venom immunotherapy is critical for the proper care of patients with hymenoptera-induced anaphylaxis.

Characteristics and Potential Biomarkers for Chronic Pain in Patients with Sickle Cell Disease

Vaso-occlusive episodes (VOE) or pain crises are a hallmark of sickle cell disease (SCD), with increasing recognition that a significant portion of SCD patients develop chronic pain. In the landmark PiSCES study (Smith et al), patients reported pain on 55% days, with ~30% reporting pain on >90% days. Thus, the episodic, nociceptive pain (VOE) in younger patients, evolves into a chronic pain syndrome, with neuropathic and centralized components in some adults. Kutlar et al (Blood, 2014), reported on the association of different pain related phenotypes (pain diaries, frequency of hospitalizations/ED visits, pressure pain threshold) with polymorphisms in candidate genes in 167 SCD patients, providing evidence that multiple signaling pathways and mechanisms are likely involved.In this study, 12 SCD subjects with "chronic pain", defined by reported pain >50% of days in pain diaries collected over 6 months, were enrolled (SCD-CP). 17 SCD patients who did not have chronic pain (SCD-NCP), and 9 non-SCD African-Americans (C) were enrolled as controls. Informed consent was obtained. Age, gender, Hb F levels, HU usage, and pressure pain algometer readings were recorded from SCD subjects. 8 ml of blood (EDTA) was collected from subjects at "steady state" and from normal controls. Plasma was separated and kept at -80 C until the assay. Plasma tryptase and Substance P levels were assayed by ELISA using kits from Biomatik, Inc. (catalog # EKU07922) and Enzo Life Sciences (Catalog #ADI-900-018), respectively. SCD-CP patients were significantly older than SCD-NCP: mean age 41 vs 32.2 (p=0.033). The pressure pain algometer readings did not differ significantly between SCD-CP and SCD-NCP at three sites (trapezius, ulna, masseter, p= 0.67-0.74). There were 12/17 patients on HU (70.6%) among SCD-NCP, and 6/12 (50%) among SCD-CP (p=0.435). Similarly, Hb F levels were not significantly different (14.7% in SCD-CP, vs 11.7% in SCD-NCP, p=0.446). Opioid use (average morphine equivalent as mg/day) was significantly higher in the chronic pain group (11.45 mg/day, vs 2.92 mg/day, p=0.015). Plasma tryptase and substance-P levels are shown in the table:Table 1Tryptase (pg/ml)Substance-P (pg/ml)SCD-CP1388.6 ±519.87221.1±7742.7SCD-NCP1023.64±221.045983.1±3473.0Control768.9±416.163939.7±1350.1The difference in substance-P levels did not reach significance across groups by ANOVA (p=0.337) or in pairwise comparison between groups. However, tryptase levels were significantly different across groups by ANOVA (p=0.00615). Pairwise comparisons between two groups showed that tryptase levels were significantly different between SCD-CP and controls (p=0.0053).These results highlight characteristics of SCD patients with chronic pain: they are older, have a higher use of opioids, and have significantly higher tryptase levels. These observations support previous findings that age is a significant factor in transition to chronic pain in SCD. Higher dose of opioid use in SCD-CP could result from dose escalation to control pain; conversely, it could be argued that higher opioid use itself could be a factor in development of chronic pain through opioid-induced hyperalgesia. To our knowledge, this is the first study of plasma tryptase levels in SCD, in relation to different pain phenotypes. Tryptase is released into plasma with degranulation of mast cells and leads to inflammation, anaphylaxis, urticaria, and neuropathic pain. It binds PAR2 (protease activated receptor 2), releasing inflammatory mediators and substance P, inducing neurogenic inflammation. Elevated tryptase levels are found in systemic mastocytosis, and the newly recognized Mast Cell Activation Syndrome (MCAS). Vincent et al (Blood, 2013) showed that mast cell activation played an important role in neurogenic inflammation and chronic pain in a mouse model of SCD. They also demonstrated that inhibition of mast cell activation, via c-kit knockout or with imatinib or cromolyn sodium improved neurogenic inflammation and chronic pain. Two recent case reports (Murphy et al, Stankovic et al) document significant improvement in pain in SCD patients who developed CML, during treatment with imatinib. These observations, and the findings of our pilot study, not only suggest a novel mechanism and biomarker for chronic pain in SCD, but also a potential therapeutic target by inhibition of mast cell activation via c-kit pathway, or stabilization with cromolyn. DisclosuresNo relevant conflicts of interest to declare.