Joanne N.G. Oude Elberink

Fatal anaphylaxis after a yellow jacket sting, despite venom immunotherapy, in two patients with mastocytosis

Death after a yellow jacket sting in otherwise healthy individuals receiving adequate immediate therapy is an u n c o m m o n occurrence. ~ Mastocytosis is overrepresented in patients first seen with anaphylaxis after insect stings, but it remains a rare disorder, even in this patient g roup2 This report describes two patients seen at our center with confirmed mastocytosis who died after a yellow jacket field sting, despite optimal treatment. Mastocytosis may be a risk factor for a severe or fatal reaction after Hymenop te ra stings in some patients with this disease.

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

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

Prevalence of indolent systemic mastocytosis in a Dutch region

REFERENCES 1. Anderson SD, Daviskas E. The mechanism of exercise-induced asthma is. J Allergy Clin Immunol 2000;106:453-9. 2. Panditi S, Silverman M. Perception of exercise induced asthma by children and their parents. Arch Dis Child 2003;88:807-11. 3. Godfrey S, Springer C, Noviski N, Maayan C, Avital A. Exercise but not methacholine differentiates asthma from chronic lung disease in children. Thorax 1991;46: 488-92. 4. Haby MM, Peat JK, Mellis CM, Anderson SD, Woolcock AJ. An exercise challenge for epidemiological studies of childhood asthma: validity and repeatability. Eur Respir J 1995;8:729-36. 5. van Leeuwen JC, Driessen JMM, de Jongh FHC, van Aalderen WMC, Thio BJ. Monitoring pulmonary function during exercise in children with asthma. Arch Dis Child 2011;96:664-8. 6. Vilozni D, Bentur L, Efrati O, Barak A, Szeinberg A, Shoseyov D, et al. Exercise challenge test in 3to 6-year-old asthmatic children. Chest 2007;132: 497-503. 7. Vilozni D, Szeinberg A, Barak A, Yahav Y, Augarten A, Efrati O. The relation between age and time to maximal bronchoconstriction following exercise in children. Respir Med 2009;103:1456-60. 8. Merikallio VJ, Mustalahti K, Remes ST, Valovirta EJ, Kaila M. Comparison of quality of life between asthmatic and healthy school children. Pediatr Allergy Immunol 2005;16:332-40. 9. Vahlkvist S, Inman MD, Pedersen S. Effect of asthma treatment on fitness, daily activity and body composition in children with asthma. Allergy 2010;65: 1464-71.

Epidemiology, Diagnosis, and Treatment of Hymenoptera Venom Allergy in Mastocytosis Patients

Hymenoptera venom allergy is a typical IgE-mediated reaction caused by sensitization to 1 or more allergens of the venom, and accounts for 1.5% to 34% of all cases of anaphylaxis. Patients suffering from mastocytosis are more susceptible to the anaphylactic reactions to an insect sting. This article aims to answer the most important clinical questions raised by the diagnosis and treatment of insect venom allergy in mastocytosis patients. Total avoidance of Hymenoptera is not feasible, and there is no preventive pharmacologic treatment available, although venom immunotherapy reduces the risk of subsequent systemic reactions.

The minimal clinically important difference of the control of allergic rhinitis and asthma test (CARAT): Cross-cultural validation and relation with pollen counts

Background:The Control of Allergic Rhinitis and Asthma Test (CARAT) monitors control of asthma and allergic rhinitis.Aims:To determine the CARAT’s minimal clinically important difference (MCID) and to evaluate the psychometric properties of the Dutch CARAT.Methods:CARAT was applied in three measurements at 1-month intervals. Patients diagnosed with asthma and/or rhinitis were approached. MCID was evaluated using Global Rating of Change (GRC) and standard error of measurement (s.e.m.). Cronbach’s alpha was used to evaluate internal consistency. Spearman’s correlation coefficients were calculated between CARAT, the Asthma Control Questionnaire (ACQ5) and the Visual Analog Scale (VAS) on airway symptoms to determine construct and longitudinal validity. Test–retest reliability was evaluated with intra-class correlation coefficient (ICC). Changes in pollen counts were compared with delta CARAT and ACQ5 scores.Results:A total of 92 patients were included. The MCID of the CARAT was 3.50 based on GRC scores; the s.e.m. was 2.83. Cronbach’s alpha was 0.82. Correlation coefficients between CARAT and ACQ5 and VAS questions ranged from 0.64 to 0.76 (P<0.01). Longitudinally, correlation coefficients between delta CARAT scores and delta ACQ5 and VAS scores ranged from 0.41 to 0.67 (P<0.01). Test–retest reliability showed an ICC of 0.81 (P<0.01) and 0.80 (P<0.01). Correlations with pollen counts were higher for CARAT than for ACQ5.Conclusions:This is the first investigation of the MCID of the CARAT. The CARAT uses a whole-point scale, which suggests that the MCID is 4 points. The CARAT is a valid and reliable tool that is also applicable in the Dutch population.

Gene expression analysis in predicting the effectiveness of insect venom immunotherapy

BACKGROUND Venom immunotherapy (VIT) enables longtime prevention of insect venom allergy in the majority of patients. However, in some, the risk of a resystemic reaction increases after completion of treatment. No reliable factors predicting individual lack of efficacy of VIT are currently available. OBJECTIVE To determine the use of gene expression profiles to predict the long-term effect of VIT. METHODS Whole genome gene expression analysis was performed on RNA samples from 46 patients treated with VIT divided into 3 groups: (1) patients who achieved and maintained long-term protection after VIT, (2) patients in whom insect venom allergy relapsed, and (3) patients still in the maintenance phase of VIT. RESULTS Among the 48.071 transcripts analyzed, 1401 showed a >2 fold difference in gene expression (P < .05); 658 genes (47%) were upregulated and 743 (53%) downregulated. Forty-three transcripts still show significant differences in expression after correction for multiple testing; 12 of 43 genes (28%) were upregulated and 31 of 43 genes (72%) downregulated. A naive Bayes prediction model demonstrated a gene expression pattern characteristic of effective VIT that was present in all patients with successful VIT but absent in all subjects with failure of VIT. The same gene expression profile was present in 88% of patients in the maintenance phase of VIT. CONCLUSION Gene expression profiling might be a useful tool to assess the long-term effectiveness of VIT. The analysis of differently expressed genes confirms the involvement of immunologic pathways described previously but also indicates novel factors that might be relevant for allergen tolerance.

CD30 in Systemic Mastocytosis

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

Changes in gene expression caused by insect venom immunotherapy responsible for the long-term protection of insect venom–allergic patients

BACKGROUND Insect venom immunotherapy (VIT) is the only causative treatment of insect venom allergy (IVA). The immunological mechanism(s) responsible for long-term protection achieved by VIT are largely unknown. A better understanding is relevant for improving the diagnosis, prediction of anaphylaxis, and monitoring and simplifying treatment of IVA. OBJECTIVE To find genes that are differentially expressed during the maintenance phase of VIT and after stopping, to get clues about the pathways involved in the long-term protective effect of immunotherapy. METHODS Whole genome gene expression analysis was performed on RNA samples from 50 patients treated with VIT and 43 healthy controls. Patients were divided into three groups: (1) before the start of VIT; (2) on maintenance phase of VIT for at least 3 years still receiving injections; and (3) after VIT. RESULTS Of all 48,804 probes present in the array, 48,773 transcripts had sufficient data for further analysis. The list of genes that were differentially expressed (at least log2 FC > 2; P < .05 corrected for multiple testing) during the maintenance phase of VIT as well as after successful VIT contains 89 entities. The function of these genes affects cell signaling, cell differentiation, and ion transport. CONCLUSION This study shows that a group of genes is differentially expressed both during and after VIT in comparison with gene expression in patients before VIT. Although the results of this study should be confirmed prospectively, the relevance of these findings is supported by the fact that they are related to putative mechanisms of immunotherapy.

Development of an allergy management support system in primary care

Background Management of allergic patients in the population is becoming more difficult because of increases in both complexity and prevalence. Although general practitioners (GPs) are expected to play an important role in the care of allergic patients, they often feel ill-equipped for this task. Therefore, the aim of this study was to develop an allergy management support system (AMSS) for primary care. Methods Through literature review, interviewing and testing in secondary and primary care patients, an allergy history questionnaire was constructed by allergists, dermatologists, GPs and researchers based on primary care and specialists’ allergy guidelines and their clinical knowledge. Patterns of AMSS questionnaire responses and specific immunoglobulin E (sIgE)-test outcomes were used to identify diagnostic categories and develop corresponding management recommendations. Validity of the AMSS was investigated by comparing specialist (gold standard) and AMSS diagnostic categories. Results The two-page patient-completed AMSS questionnaire consists of 12 (mainly) multiple choice questions on symptoms, triggers, severity and medication. Based on the AMSS questionnaires and sIgE-test outcome of 118 patients, approximately 150 diagnostic categories of allergic rhinitis, asthma, atopic dermatitis, anaphylaxis, food allergy, hymenoptera allergy and other allergies were identified, and the corresponding management recommendations were formulated. The agreement between the allergy specialists’ assessments and the AMSS was 69.2% (CI 67.2–71.2). Conclusion Using a systematic approach, it was possible to develop an AMSS that allows for the formulation of diagnostic and management recommendations for GPs managing allergic patients. The AMSS thus holds promise for the improvement of the quality of primary care for this increasing group of patients.

Diminished reliability of tryptase as risk indicator of mastocytosis in older overweight subjects.

BACKGROUND Currently, measurement of serum tryptase level is the most commonly used test to estimate the need for bone marrow biopsy in patients suspected to have indolent systemic mastocytosis (ISM). Yet tryptase levels do not solely reflect the mast cell load and can be elevated by overweight, older age, and impaired renal function. The influence of these factors on urinary methylhistamine (MH) and methylimidazole acetic acid (MIMA) is still unknown. OBJECTIVE We investigated the impact of age, body mass index (BMI), and kidney function on the diagnostic accuracy of tryptase, MH, and MIMA to select the most optimal test indicating the necessity of a bone marrow biopsy in ISM-suspected patients. METHODS Retrospective data analysis of all adults in whom bone marrow investigations were performed because of high clinical suspicion and/or elevated tryptase, MH, or MIMA. RESULTS 194 subjects were included. ISM was present in 112 and absent in 82 subjects (non-ISM). Tryptase was elevated by age and body weight in non-ISM subjects and by BMI in ISM subjects; however, these factors did not influence MH or MIMA. In the total study population, the diagnostic accuracy of tryptase, MH, and MIMA were comparable (area under the curve 0.80, 0.80, and 0.83). In subjects >50 years with a BMI >25 kg/m(2), the diagnostic accuracy of MIMA was higher compared with that of tryptase (area under the curve 0.93 vs 0.74; P = .011). CONCLUSION In ISM-suspected patients >50 years with a BMI of >25 kg/m(2), MIMA has a greater value compared with tryptase in estimating the need for bone marrow biopsy.