Measurement of IgE to hazelnut allergen components cannot replace hazelnut challenge in Dutch adults.

BACKGROUND: Component-resolved diagnostics (CRD) help predict hazelnut allergy (HA) in children, but are of unknown diagnostic value in adults. This study aimed to evaluate the diagnostic accuracy of IgE to hazelnut extract and components in adults. METHODS: A Dutch population of consecutively presenting adults suspected of HA, who underwent a double-blind placebo-controlled food challenge, were included. Serum IgE to hazelnut extract and Cor a 1, 8, 9, and 14 was measured on ImmunoCAP. Diagnostic accuracy was assessed by area under the curve (AUC) analysis. RESULTS: Of 89 patients undergoing challenge, 46 had challenge-confirmed HA: 17 based on objective and 29 based on subjective symptoms. At commonly applied cutoffs 0.1 and 0.35 kUA /L, high sensitivity was observed for IgE to hazelnut extract and Cor a 1 (range 85-91%), and high specificity for IgE to Cor a 8, 9 and 14 (range 77-95%). However, the AUCs for hazelnut extract and components were too low for accurate prediction of HA (range 0.50-0.56). Combining hazelnut extract and component IgE measurements did not significantly improve accuracy. Higher IgE levels to Cor a 9 and 14 were tentatively associated with HA with objective symptoms, but the corresponding AUCs still only reached 0.68 and 0.63, respectively. CONCLUSIONS: Although hazelnut allergic adults are generally sensitized to hazelnut extract and Cor a 1, and hazelnut tolerant adults are usually not sensitized to Cor a 8, 9, or 14, challenge testing is still needed to accurately discriminate between presence and absence of HA in adults from a birch-endemic country.

Diagnostic accuracy of Ara h 2 for detecting peanut allergy in children.

BACKGROUND: Specific IgE to Ara h 2 is a diagnostic test for peanut allergy which may reduce the need for double-blind placebo-controlled food challenges (DBPCFC); however, guidance for using Ara h 2 in place of DBPCFCs has not been validated. OBJECTIVE: To prospectively evaluate 1) diagnostic accuracy of previously published Ara h 2 cut-off levels to diagnose peanut allergy in children and 2) costs. METHODS: A consecutive series of 150 children age 3.5 to 18 years was evaluated in secondary and tertiary settings in the Netherlands. sIgE to Ara h 2 was the index test, and oral peanut ingestion was the reference test. Oral peanut ingestion was home or supervised introduction for Ara h 2 ≤ 0.1, DBPCFC for 0.1-5.0 and open food challenge for ≥5.0. Costs were calculated using financial healthcare data. RESULTS: A conclusive reference test was performed in 113 children (75%). Sixty-four children (57%) had peanut allergy, as confirmed by a DBPCFC (27/47) or an open challenge (37/50). Forty-nine children (43%) were considered peanut-tolerant after peanut introduction (19/19), a DBPCFC (20/47) or an open challenge (10/50). Area under the curve for Ara h 2 was 0.94 (95% CI 0.90-0.98). The diagnostic flow chart correctly classified 26/26 (100%; 84-100) of children with Ara h 2 ≤ 0.1 as peanut-tolerant and 34/35 (97%; 83-100) of children with Ara h 2 ≥ 5.0 as peanut-allergic. At a cut-off of ≤0.1 and ≥5.0, a sensitivity of respectively 100% (93-100) and 53% (38-67) was observed and a specificity of 53% (38-67) and 98% (87-100). Mean annual costs of the flow chart were estimated as €320-€636 per patient lower than following national allergy guidelines. CONCLUSIONS: In this diagnostic accuracy study, which did not take into account pretest probability, we have validated previously published Ara h 2 cut-off levels which are associated with peanut tolerance and allergy.

Perceived triggers of asthma impair quality of life in children with asthma.

BACKGROUND: Data on the impact of the number and nature of perceived asthma triggers on health-related quality of life (HRQL) in children are scarce. OBJECTIVE: To investigate the impact of perceived asthma triggers on both asthma-specific and generic HRQL in children. METHODS: A cross-sectional study was conducted among children (7-18 years) with asthma in secondary and tertiary care. Children were screened with electronic questionnaires regarding respiratory and allergic symptoms. Asthma-specific HRQL was assessed using the Pediatric Asthma Quality of Life Questionnaire (PAQLQ) (score range 1-7) and generic HRQL using the RAND questionnaire (score range 7-32). The Kruskal-Wallis test and one-way ANOVA were used to test the difference of, respectively, the PAQLQ and RAND scores across the number of perceived asthma triggers (0, 1-2, 3-4, or ≥ 5). Univariable and multivariable linear regression analyses were performed to evaluate the association between individual triggers and HRQL. RESULTS: A total of 527 children with a mean (SD) age of 12.1 (2.9) years were included. Children with a higher number of perceived triggers had significantly lower PAQLQ and RAND scores (ie poorer HRQL). The difference in PAQLQ scores was clinically relevant between children with 0 versus 3-4 or ≥ 5 triggers and 1-2 versus ≥ 5 triggers (mean difference 0.66, 1.02 and 0.63, respectively). Especially, non-allergic triggers (physical exercise, the weather, (cigarette) smoke and emotions) were significantly associated with reduced PAQLQ scores. Emotions and food/drinks were associated with reduced RAND scores. CONCLUSION AND CLINICAL RELEVANCE: A higher number of perceived triggers of asthma were associated with reduced HRQL in children with asthma. Especially, non-allergic triggers were associated with reduced HRQL.

The impact of oral food challenges for food allergy on quality of life: A systematic review.

BACKGROUND: Food allergy significantly impairs health-related quality of life (HRQL). Currently, it is still unknown whether diagnostic interventions for food allergy improve HRQL. We aim to assess the impact of diagnostic interventions for food allergy on HRQL. METHODS: A systematic search was performed in MEDLINE, Embase, Cochrane Library, and CINAHL focused on patients with a (suspected) food allergy who underwent diagnostic interventions (ie, skin prick test, specific IgE, or oral food challenges [OFC]) and in whom HRQL was assessed. The mean difference between HRQL before and after the diagnostic intervention was calculated. A minimal clinically important difference of 0.5 was considered clinically relevant for the food allergy quality of life questionnaire. RESULTS: Seven of 1465 original identified publications were included in which the impact of an OFC on HRQL was investigated (total patients n = 1370). No other diagnostic interventions were investigated. Food allergy-specific parent-reported HRQL improved significantly after an OFC irrespective of the outcome in children with a suspected food allergy in two publications. The change was considered clinically relevant in one of two publications. In addition, parent-reported HRQL improved after an OFC to assess the eliciting dose in children with a confirmed food allergy. The parental burden was significantly reduced after an OFC to assess resolution of food allergy. A meta-analysis could not be performed due to the limited numbers of, and considerable heterogeneity between, eligible publications. CONCLUSION: An OFC is associated with an improved food allergy-specific HRQL and a reduced parental burden of food allergy.

Less Anti-infliximab Antibody Formation in Paediatric Crohn Patients on Concomitant Immunomodulators.

OBJECTIVES: To evaluate the effect of immunomodulators on formation of antibodies to infliximab (ATI) in paediatric patients with Crohn disease (CD) and the association of ATI and loss of response. METHODS: Retrospective multicentre observational study (January 2009-December 2014) among Dutch children with CD treated with infliximab (IFX). ATI formation was analysed with Chi-square test and time-to-ATI formation with Kaplan-Meier and log-rank test. RESULTS: A total of 229 children were identified. ATIs were measured in 162 patients (70.7%) and 25 (15%) developed ATIs: 6 of 62 (10%) on continuous combined immunosuppression (CCI), 11 of 81 (14%) on early combined immunosuppression (ECI), and 8 of 19 (42%) on IFX monotherapy. ATI formation was higher in patients on IFX monotherapy compared to CCI (P = 0.003) and ECI (P = 0.008), whereas no significant difference was found between CCI and ECI. Sixteen out of 25 patients (64%) with ATIs had loss of response, compared with 32 of 137 patients (19%) without ATIs (P < 0.00002, log rank 0.02). Among patients treated with ECI, 10 of 55 (18%) developed ATIs within the first 12 months, compared to 1 of 26 (4%) after more than 12 months. CONCLUSIONS: In children with CD combination therapy is associated with significant reduction of antibody formation and prolonged effectivity compared to IFX monotherapy. ECI for at least 12 months, followed by IFX monotherapy, may be an equally effective alternative to CCI.

Accurate Prediction of Peanut Allergy in One-Third of Adults Using a Validated Ara h 2 Cutoff.

BACKGROUND: The diagnostic value of peanut components is extensively studied in children, but to a lesser extent in adults with suspected peanut allergy. The use of peanut components in daily practice may reduce the need for double-blind placebo-controlled food challenges (DBPCFCs); however, validation studies are currently lacking. OBJECTIVE: To evaluate the diagnostic value of (combined) peanut components and validate a previously found Ara h 2 cutoff level with 100% positive predictive value (PPV) in adults with suspected peanut allergy. METHODS: Adults who underwent a peanut DBPCFC were included: 84 patients from a previous study (2002-2012) and 70 new patients (2012-2019). Specific IgE (sIgE) to peanut extract, Ara h 1, 2, 3, 6, and 8 was measured using ImmunoCAP. Diagnostic value was assessed with an area under the curve (AUC) analysis. RESULTS: In total, 95 (62%) patients were peanut allergic. sIgE to Ara h 2 and Ara h 6 were the best predictors with an AUC (95% confidence interval) of 0.85 (0.79-0.91) and 0.85 (0.79-0.92), respectively. The Ara h 2 cutoff level with 100% PPV (≥1.75 kUA/L) was validated in the 70 new patients. Thirty percent of all included patients could be classified correctly as peanut allergic using this validated cutoff level. CONCLUSION: sIgE to Ara h 2 and Ara h 6 have equally high discriminative ability. Peanut allergy can be predicted accurately in one-third of adults using a validated cutoff level of sIgE to Ara h 2.

Risk factors for atopic diseases and recurrent respiratory tract infections in children.

INTRODUCTION: The simultaneously increased prevalence of atopic diseases and decreased prevalence of infectious diseases might point to a link between the two entities. Past work mainly focused on either atopic diseases or recurrent infections. We aim to investigate whether risk factors for atopic diseases (ie, asthma, allergic rhinitis, atopic dermatitis, and/or food allergy) differ from risk factors for recurrent respiratory tract infections (RRTIs) in children. METHODS: Cross-sectional data were used from 5517 children aged 1 to 18 years who participated in an Electronic Portal for children between 2011 and 2019. Univariable/multivariable logistic regression analyses were performed to determine risk factors for any atopic disease and RRTIs. RESULTS: Children aged ≥5 years were more likely to have any atopic disease (adjusted odds ratio [OR]: 1.50-2.77) and less likely to have RRTIs (OR: 0.68-0.84) compared to children aged less than 5 years. Female sex (OR: 0.72; 95% confidence interval [CI]: 0.63-0.81), low birth weight (OR: 0.74; 95% CI: 0.57-0.97) and dog ownership (OR: 0.79; 95% CI: 0.66-0.95) reduced the odds of any atopic disease, but not of RRTIs. Daycare attendance (OR: 1.22; 95% CI: 1.02-1.47) was associated with RRTIs, but not with atopic diseases. A family history of asthma, allergic rhinitis, atopic dermatitis, and RRTIs was significantly associated with the same entity in children, with OR varying from 1.58 (95% CI: 1.35-1.85) in allergic rhinitis to 2.20 (95% CI: 1.85-2.61) in asthma. CONCLUSION: Risk factors for atopic diseases are distinct from risk factors for RRTIs, suggesting that the changing prevalence of both entities is not related to shared risk factors.

Peripheral Stem Cell Apheresis is Feasible Post 131Iodine-Metaiodobenzylguanidine-Therapy in High-Risk Neuroblastoma, but Results in Delayed Platelet Reconstitution.

PURPOSE: Targeted radiotherapy with 131iodine-meta-iodobenzylguanidine (131I-MIBG) is effective for neuroblastoma (NBL), although optimal scheduling during high-risk (HR) treatment is being investigated. We aimed to evaluate the feasibility of stem cell apheresis and study hematologic reconstitution after autologous stem cell transplantation (ASCT) in patients with HR-NBL treated with upfront 131I-MIBG-therapy. EXPERIMENTAL DESIGN: In two prospective multicenter cohort studies, newly diagnosed patients with HR-NBL were treated with two courses of 131I-MIBG-therapy, followed by an HR-induction protocol. Hematopoietic stem and progenitor cell (e.g., CD34+ cell) harvest yield, required number of apheresis sessions, and time to neutrophil (>0.5 × 109/L) and platelet (>20 × 109/L) reconstitution after ASCT were analyzed and compared with "chemotherapy-only"-treated patients. Moreover, harvested CD34+ cells were functionally (viability and clonogenic capacity) and phenotypically (CD33, CD41, and CD62L) tested before cryopreservation (n = 44) and/or after thawing (n = 19). RESULTS: Thirty-eight patients (47%) were treated with 131I-MIBG-therapy, 43 (53%) only with chemotherapy. Median cumulative 131I-MIBG dose/kg was 0.81 GBq (22.1 mCi). Median CD34+ cell harvest yield and apheresis days were comparable in both groups. Post ASCT, neutrophil recovery was similar (11 days vs. 10 days), whereas platelet recovery was delayed in 131I-MIBG- compared with chemotherapy-only-treated patients (29 days vs. 15 days, P = 0.037). Testing of harvested CD34+ cells revealed a reduced post-thaw viability in the 131I-MIBG-group. Moreover, the viable CD34+ population contained fewer cells expressing CD62L (L-selectin), a marker associated with rapid platelet recovery. CONCLUSIONS: Harvesting of CD34+ cells is feasible after 131I-MIBG. Platelet recovery after ASCT was delayed in 131I-MIBG-treated patients, possibly due to reinfusion of less viable and CD62L-expressing CD34+ cells, but without clinical complications. We provide evidence that peripheral stem cell apheresis is feasible after upfront 131I-MIBG-therapy in newly diagnosed patients with NBL. However, as the harvest of 131I-MIBG-treated patients contained lower viable CD34+ cell counts after thawing and platelet recovery after reinfusion was delayed, administration of 131I-MIBG after apheresis is preferred.