Clinical management of plant food allergy in patients sensitized to lipid transfer proteins is heterogeneous: identifying the gaps

BACKGROUND AND OBJECTIVE

Patients sensitized to lipid transfer protein (LTP) present a wide clinical variability. The lack of practical diagnostic and therapeutic guidelines complicate their management. The aim of the study was to describe the clinical approach of Spanish allergists to this pathology using a survey designed by PICO method and subsequent Delphi approach validation.

METHODS

Designed survey was answered by 224 allergists (75% women; 57.1% with >20 years of professional experience). Homogeneity regarding clinical practice on the main points of LTP allergy diagnosis was observed, except for patients with suspected NSAID hypersensitivity (44.6% frequently include LTP skin testing). Oral food challenges were not frequently performed (63.6% occasionally to never), and they were generally (75.5%) used to confirm tolerance. It was common to recommend fruit skins avoidance (77.2%) and maintaining consumption of foods to which patients are sensitised but tolerant (99.1%).

RESULTS

There was heterogeneity on other dietary indications, modifications due to co-factors, or traces avoidance. Peach sublingual immunotherapy (SLIT) was considered very/quite effective by 55.9% of allergists. The majority (79.5%) consider SLIT indicated in <25% of LTP allergic patients, based on severity (95.2%), frequency of reactions (99.4%), allergy to multiple food families (97.4%), and the quality of life/nutrition impairment (91.5%). There was different practice on SLIT prescription based on co-factor involvement.

CONCLUSION

These data suggest that there is a need to increase evidence to reduce the clinical practice heterogeneity in the management of LTP allergy.

Local allergic rhinitis in children: Clinical characteristics and role of basophil activation test as a diagnostic tool

BACKGROUND

Local allergic rhinitis (LAR) is a condition involving a localized nasal allergic response in absence of systemic atopy. Most studies on LAR have been performed in adults. We aimed to describe clinical characteristics of LAR pediatric patients, its clinical evolution over a 7-year follow-up period and to study the role of basophil activation test (BAT), for its diagnosis.

METHODS

Forty-four children with non-allergic rhinitis (NAR) were included (24 males, 20 females, aged under 15 years). Nasal allergen provocation test (NAPT) and BAT were performed with Dermatophagoides pteronyssinus and Phleum pratense.

RESULTS

Seven patients (16%) were diagnosed of LAR. Six reacted to D pteronyssinus and one to P pratense. All LAR and 86% of NAR patients presented perennial symptoms. Fifty-seven percent of NAR and LAR patients referred persistent symptoms. Around half of NAR and LAR patients reported mild-moderate clinical manifestations. Three LAR patients associated conjunctival symptoms, proportionally more than NAR patients (19%, 7 out of 37). NAR patients presented bronchial asthma (n = 10) more frequently than LAR children (n = 1). More than half of LAR and NAR patients presented family history of atopy. BAT was negative in all LAR patients. On follow-up, 3 LAR patients and 10 of the 25 NAR patients who agreed to be retested, presented systemic sensitization. Dust mites were the most frequent allergen involved.

CONCLUSIONS

LAR should be ruled out in children with NAR. Almost half of children with LAR develop systemic sensitization over time. BAT shows low sensitivity for the diagnosis of LAR in children.

Unraveling Kiwifruit Allergy Diagnosis: Usefulness of the Current Diagnostic Tests

OBJECTIVES

To determine the usefulness of the in vitro and in vivo methods used in the diagnosis of kiwifruit allergy, focusing on the impact of the seed proteins on their sensitivity.

MATERIAL AND METHODS

Skin prick tests (SPTs) using different commercial extracts, homemade pulp and seed extracts, and prick-prick test with kiwifruit were performed on 36 allergic patients. The presence of specific IgE (sIgE) was assessed using ImmunoCAP (kiwifruit extract), ELISA (Act d 1, Act d 2), ISAC and FABER assays. Immunoblotting of seed extract was carried out, and a single blinded oral food challenge with whole seeds was performed in seed-sensitized subjects.

RESULTS

The prick prick test with kiwifruit demonstrated the highest diagnostic capacity (81.8% sensitivity and 94.1% specificity) among the in vivo tests. The sIgE levels measured by ImmunoCAP-kiwifruit extract showed a similar sensitivity to that of global ISAC and FABER (63.9%, 59.5% and 58.3%, respectively). Act d 1 was the major allergen, and sensitization to it was associated with positive sIgE to whole kiwifruit extract detected by ImmunoCAP (p <0.000). A positive SPT with kiwifruit seeds was associated with severe symptoms with kiwifruit (p = 0.019) as a marker of an advanced disease, but not with clinically relevant sensitization. The challenge to kiwifruit seeds performed on eight seed-sensitized patients resulted negative.

CONCLUSION

Sensitization to Act d 1 is related to a positive result in conventional diagnostic techniques, whereas kiwifruit seed sensitization does not increase the sensitivity of the evaluated diagnostic techniques.

Mechanisms, Cofactors, and Augmenting Factors Involved in Anaphylaxis

Anaphylaxis is an acute and life-threatening systemic reaction. Many triggers have been described, including food, drug, and hymenoptera allergens, which are the most frequently involved. The mechanisms described in anaphylactic reactions are complex and implicate a diversity of pathways. Some of these mechanisms may be key to the development of the anaphylactic reaction, while others may only modify its severity. Although specific IgE, mast cells, and basophils are considered the principal players in anaphylaxis, alternative mechanisms have been proposed in non-IgE anaphylactic reactions. Neutrophils, macrophages, as well as basophils, have been involved, as have IgG-dependent, complement and contact system activation. A range of cationic substances can induce antibody-independent mast cells activation through MRGPRX2 receptor. Cofactors and augmenting factors may explain why, in some patients, food allergen exposure can cause anaphylaxis, while in other clinical scenario it can be tolerated or elicits a mild reaction. With the influence of these factors, food allergic reactions may be induced at lower doses of allergen and/or become more severe. Exercise, alcohol, estrogens, and some drugs such as Non-steroidal anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, β-blockers, and lipid-lowering drugs are the main factors described, though their mechanisms and signaling pathways are poorly understood.

Comparable actions of omalizumab on mast cells and basophils

BACKGROUND

Omalizumab (OmAb) has recently been approved for the treatment of diseases other than allergic asthma, including chronic urticaria. The exploration of the use of OmAb in chronic urticaria was based on the presence of IgE autoantibodies against autoantigens such as anti-IgE, anti-FcεRI, and IgE antibodies against thyroid peroxidase in certain patients with chronic urticaria. OmAb recognizes and sequesters free IgE to prevent its interaction with FcεRI. However, OmAb is equally and rapidly effective against autoimmune and non-autoimmune urticaria, suggesting the possible involvement of additional mechanisms of IgE.

OBJECTIVES

We sought to investigate the in vitro mechanism of action of OmAb in mast cells and basophils.

METHODS

Both LAD2 human mast cell line, previously sensitized with IgE, and ex vivo basophils were incubated with OmAb at different doses, analysing its effect on IgE-dependent events (e.g., degranulation, phosphorylation-mediated signalling, and eicosanoid release).

RESULTS

We found that OmAb dissociates pre-bound IgE from mast cells and basophils, resulting in a reduction of proximal phosphorylation-mediated signalling events (Syk, PLCγ, and LAT) and in a decrease in degranulation and leukotriene synthesis.

CONCLUSION

Our data prove the existence of common mechanisms of action of OmAb in mast cells and basophils that would explain its effectiveness and rapid effect in chronic urticaria and provide a basis for its use in other diseases mediated by these cells.

Is Microarray Analysis Really Useful and Sufficient to Diagnose Nut Allergy in the Mediterranean Area?

BACKGROUND

Component-based diagnosis on multiplex platforms is widely used in food allergy but its clinical performance has not been evaluated in nut allergy.

OBJECTIVE

To assess the diagnostic performance of a commercial protein microarray in the determination of specific IgE (sIgE) in peanut, hazelnut, and walnut allergy.

METHODS

sIgE was measured in 36 peanut-allergic, 36 hazelnut-allergic, and 44 walnut-allergic patients by ISAC 112, and subsequently, sIgE against available components was determined by ImmunoCAP in patients with negative ISAC results. ImmunoCAP was also used to measure sIgE to Ara h 9, Cora 8, and Jug r 3 in a subgroup of lipid transfer protein (LTP)-sensitized nut-allergic patients (positive skin prick test to LTP-enriched extract). sIgE levels by ImmunoCAP were compared with ISAC ranges.

RESULTS

Most peanut-, hazelnut-, and walnut-allergic patients were sensitized to the corresponding nut LTP (Ara h 9, 66.7%; Cor a 8, 80.5%; Jug r 3, 84% respectively). However, ISAC did not detect sIgE in 33.3% of peanut-allergic patients, 13.9% of hazelnut-allergic patients, or 13.6% of walnut-allergic patients. sIgE determination by ImmunoCAP detected sensitization to Ara h 9, Cor a 8, and Jug r 3 in, respectively, 61.5% of peanut-allergic patients, 60% of hazelnut-allergic patients, and 88.3% of walnut-allergic patients with negative ISAC results. In the subgroup of peach LTP-sensitized patients, Ara h 9 sIgE was detected in more cases by ImmunoCAP than by ISAC (94.4% vs 72.2%, P < .05). Similar rates of Cora 8 and Jug r 3 sensitization were detected by both techniques.

CONCLUSIONS

The diagnostic performance of ISAC was adequate for hazelnut and walnut allergy but not for peanut allergy. sIgE sensitivity against Ara h 9 in ISAC needs to be improved.

Do Skin Prick Test and In Vitro Techniques Diagnose Sensitization to Peach Lipid Transfer Protein and Profilin Equally Well in Allergy to Plant Food and Pollen?

OBJECTIVE

To compare the skin prick test (SPT) with in vitro techniques (single and multiplex fluorescence enzyme-immunoassay [FEIA]) for detecting sensitization to profilin and lipid transfer protein (LTP).

METHODS

We retrospectively studied 181 patients with pollen and/or plant food allergy and 61 controls. SPT was performed with date palm profilin (Pho d 2) and peach LTP (Pru p 3), and specific IgE (sIgE) to Phl p 12 and Pru p 3 was analyzed using single FEIA and microarray.

RESULTS

Fifteen of 201 patients with negative results for LTP in the SPT were sensitized to this allergen in the in vitro tests, and 18 of 41 patients with positive results for LTP in the SPT were not sensitized according to the in vitro tests. Seventeen of 186 patients with negative results for profilin in the SPT were sensitized to Phl p 12 by serum sIgE, and 30 out of 56 patients with positive results for profilin in SPT were not sensitized to Phl p 12 according to the other tests. Moderate agreement was observed between the 3 techniques studied.

CONCLUSIONS

SPT is a sensitive technique for detecting sensitization to LTP and profilin. Its results are similar to those of in vitro techniques, especially in patients with negative SPT results for peach LTP and palm tree profilin.

In vivo and in vitro testing with rAni s 1 can facilitate diagnosis of Anisakis simplex allergy

BACKGROUND

Traditional diagnostic tests such as skin prick tests (SPT) and specific IgE (slgE) against whole Anisakis simplex extract have low specificity. Consequently, allergy to A simplex is overdiagnosed.

OBJECTIVE

Our aim was to compare tests used in component-resolved diagnosis.

METHODS

We evaluated 34 patients with allergy to A simplex, 15 patients with acute urticaria who were sensitized to A simplex but had no clinical history of allergy to A simplex, and 10 patients allergic to seafood. SPT, slgE (ELISA and ISAC-I 12), and the basophil activation test (BAT) were performed with A simplex whole extract and the molecular components rAni s 1, rAni s 3, and nPen m 1. Sensitivity and specificity were calculated and compared with different cutoffs.

RESULTS

With the A simplex whole extract, SPT, slgE, and BAT yielded specificity values of 72%, 68%, and 70%, respectively, with a cutoff (wheal size) of 11.2 mm, an slgE value of 7.9 kUAIL, and a stimulation index of 1.9. Specificity increased to 100% using the molecular component rAni s 1 with SPT, slgE by ELISA, and ISAC-112. Neither rAni s 3 sensitization nor cross-reactivity with Pen m 1 was observed in patients sensitized to A simplex.

CONCLUSION

rAni s 1 is recognized by 100% of our patients and is able to distinguish between patients allergic to A simplex and patients with acute urticaria who are sensitized to A simplex but have no clinical history of allergy to this parasite.

Recommendations for the use of in vitro methods to detect specific immunoglobulin E: are they comparable?

Total and specific immunoglobulin (Ig) E can be detected in vitro using several commercially available methods. The largest share of the global market for these methods is held by the ImmunoCAP technique (Thermo Fisher, previously Phadia), Immulite (Siemens), and Hytec-288 (Hycor). Most comparative studies examine Immulite and ImmunoCAP, which differ methodologically but use similar units of measurement relative to the same standard of total IgE (WHO IgE Standard 75/502). Despite their similarity, these kits differ in their quantification of specific IgE, which varies depending on the allergen studied.Thus, specific IgE results obtained with ImmunoCAP and Immulite are not interchangeable. It is important to bear this in mind, especially when determining cutoff points as predictors of a response to oral challenge with specific food allergens. The method used in practice must be the same as the one in the publication guiding clinical decision making. We analyze differences between ImmunoCAP and ISAC microarray, 2 methods from the same manufacturer used to detect IgE to specific proteins (purified or recombinant).The results show that the IgE values obtained with ImmunoCAP are not equivalent to the corresponding values obtained with the ISAC microarray system.

Performance of different in vitro techniques in the molecular diagnosis of peanut allergy

INTRODUCTION

Peanut allergy is an increasingly serious disorder with a heterogeneous pattern of sensitization across different countries. In vitro diagnostic techniques may help in establishing these patterns.

OBJECTIVES

To analyze the usefulness of determining specific immunoglobulin E (sIgE) with the ImmunoCAP fluorescence enzyme immunoassay (FEIA), the ImmunoCAP ISAC CRD103 microarray (ISAC), and the basophil activation test (BAT) in the molecular diagnosis of peanut allergy.

METHODS

In 26 peanut-allergic patients, sIgE antibodies against allergic components were measured with FEIA, ISAC, and BAT.

RESULTS

The major peanut component in our population wasAra h 9.The detection of sIgE toAra h 9 using FEIA and BAT with this allergen yielded a sensitivity of 92% and 88% and a specificity of 95% and 100%, respectively. Overall diagnosis of peanut allergy by ISAC showed a sensitivity of 11% but a specificity of 95% since Ara h 9 was not present in the microarray version used. There was diagnostic agreement between the 3 techniques for the peanut allergens studied.

CONCLUSIONS

The determination of sIgE to Ara h 9 using FEIA and BAT offers high sensitivity and specificity in the diagnosis of peanut allergy in the Spanish population. The CRD103 version of ISAC is not of value in our region as it does not include the most common allergen, Ara h 9.

A new rapid desensitization protocol for chemotherapy agents

BACKGROUND

Desensitization has been used for some decades to treat patients with the allergenic drug when an alternative drug with similar efficacy and safety is not available. We present the results from a series of oncology patients desensitized at our hospital during the last 2 years.

OBJECTIVE

To assess the efficacy of a new desensitization protocol in patients allergic to chemotherapy drugs.

METHODS

We performed an observational retrospective study of 11 women (6 breast cancer and 5 ovarian cancer) who underwent our desensitization protocol. Four patients had immediate reactions to carboplatin, 3 to docetaxel, 3 to paclitaxel, and 1 to both docetaxel and paclitaxel. Premedication was administered in all cases. A 5-step protocol based on 5 different dilutions of the drugs was used.

RESULTS

We performed 39 desensitization procedures: 14 to carboplatin, 3 to oxaliplatin, 16 to docetaxel, and 6 to paclitaxel. Eight patients tolerated the full dose in 36 procedures. One patient suffered an anaphylactic reaction to carboplatin that reverted with treatment. One patient had dyspnea after a paclitaxel cycle. One patient experienced dyspnea due to chronic pulmonary thromboembolism related to her disease.

CONCLUSION

Desensitization is a useful procedure in patients who are allergic to their chemotherapy agents.

Component-resolved in vitro diagnosis in peach-allergic patients

BACKGROUND

The in vitro diagnosis of pollen-related food allergy presents low specificity and reproducibility with many conventional extracts. This can be improved using natural purified allergens, recombinant purified allergens, or both.

OBJECTIVE

We compared specific immunoglobulin (Ig) E determination (slgE), the basophil activation test (BAT), the histamine release test (HRT), and the cellular allergen stimulation test (CAST) using natural and recombinant allergens in the diagnosis of peach allergy.

METHODS

Thirty-two peach allergic patients were studied. Skin prick tests were performed with commercial peach and extract with Mal d 1, nPru p 3, and profilin (nPho d 2). slgE, BAT, CAST, and HRT were determined using rPru p 3, rMal d 3, rBet v 1, rMal d 1, and rMal d 4.

RESULTS

Agreement between the techniques was good with all the allergens, except HRT with rMal d 1 and rMal d 4. With rPru p 3, slgE, CAST, BAT, and HRT showed sensitivity values of 88%, 81%, 72%, and 69% and specificity values of 100%, 93%, 97%, and 83%, respectively. In patients with systemic symptoms or contact urticaria, the values were 100%, 85%, 81%, and 81%. In patients with oral allergy syndrome, sensitivity to profilins or homologues of Bet v 1 was detected in 100% of the cases by all the techniques, except by HRT with rMal d 1, which detected 66% of the cases.

CONCLUSIONS

The use of single allergens in the in vitro diagnosis of peach allergy by specific IgE determination, BAT, and CAST offers high specificity and sensitivity, with better results than the HRT.

[Lung transplant]

A lung transplant is usually the final therapeutic option for patients with respiratory insufficiency. In spite of the many advances in immunology and the management of complications, mortality and morbidity associated with this transplant are far higher than with others. Acute rejection is an almost universal problem in the first year, while obliterative bronchitis reduces long term survival. Respiratory infections also play a significant role in the complications associated with lung transplants due to the constant exposure of the graft to the outside. However, the success of this therapeutic option, which basically depends on a suitable selection of donor and recipient, are evident, above all with respect to quality of life.