Double-blind, placebo-controlled food challenge in adults in everyday clinical practice: a reappraisal of their limitations and real indications

The diagnosis and management of allergic reactions in patients sensitized to non-specific lipid transfer proteins

Sensitization to one or more non-specific lipid transfer proteins (nsLTPs), initially thought to exist mainly in southern Europe, is becoming accepted as a cause of allergic reactions to plant foods across Europe and beyond. The peach nsLTP allergen Pru p 3 is a dominant sensitizing allergen and peaches a common food trigger, although multiple foods can be involved. A frequent feature of reactions is the requirement for a cofactor (exercise, alcohol, non-steroidal anti-inflammatory drugs, Cannabis sativa) to be present for a food to elicit a reaction. The variability in the food and cofactor triggers makes it essential to include an allergy-focused diet and clinical history in the diagnostic workup. Testing on suspected food triggers should also establish whether sensitization to nsLTP is present, using purified or recombinant nsLTP allergens such as Pru p 3. The avoidance of known trigger foods and advice on cofactors is currently the main management for this condition. Studies on immunotherapy are promising, but it is unknown whether such treatments will be useful in populations where Pru p 3 is not the primary sensitizing allergen. Future research should focus on the mechanisms of cofactors, improving diagnostic accuracy and establishing the efficacy of immunotherapy.

Lactose Sensitivity and Lactose Malabsorption: The 2 Faces of Lactose Intolerance

Background/Aims

Self-reported lactose intolerance (LI) is frequent in patients with functional bowel disorders (FBD) that could be interpreted as irritable bowel syndrome (IBS). The present study aims to characterize the responses of patients with FBD, without small intestinal bacterial overgrowth (SIBO), and LI, in terms of lactose malabsorption (LM) and lactose sensitivity (LS) according to psychological and clinical features.

Methods

One hundred and fifty-eight consecutive FBD outpatients with LI, and no SIBO, were classified according to the Rome III questionnaire and filled Beck Depression Inventory, and State and Trait Anxiety questionnaires. They underwent a lactose tolerance test in which glycemia during 60 minutes and digestive symptoms for 3 hours were recorded.

Results

Abnormal lactose tolerance tests were found in 110 patients (70%), 44 (28%) with LM, 96 (61%) with LS, and 30 (19%) having both LM and LS. LM patients had a higher frequency of functional diarrhea (P = 0.040) and a lower frequency of dysphagia (P = 0.031). LS patients had a higher depression score (P = 0.007), higher frequency of globus (P = 0.042), irritable bowel syndrome (IBS) (P = 0.027) and mixed IBS (P = 0.049), and lower frequency of abdominal pain (P = 0.040). LS was significantly associated with a higher depression score (P = 0.002), and a higher frequency of globus (P = 0.046).

Conclusions

Thirty percent of LI patients have normal lactose absorption and normal LS. In the other 70% of patients, LI could be associated with LM and/or LS.

Natural History of IgE-Mediated Fish Allergy in Children

BACKGROUND

Fish allergy is not uncommon, especially in countries with high fish consumption, it can frequently be severe and may affect dietetic and lifestyle choices. Nevertheless, data on its clinical course and natural history are scarce.

OBJECTIVE

To describe the natural history of immunoglobulin E-mediated fish allergy and the potential differential reactivity to various fish species and identify prognostic markers in children with confirmed disease.

METHODS

Clinical history, specific immunoglobulin E, and skin prick tests to various fish were recorded in 126 children with confirmed immunoglobulin E-mediated fish allergy. Immunoglobulin E reactivity was also evaluated by immunoblotting. Eligible participants proceeded to a series of food challenges to tuna, swordfish, and codfish. In total, 234 challenges were performed.

RESULTS

Fifty-eight children (9.7 ± 3.9 years) were included in the analysis. Age at first reaction was 0.5 to 5 years (median, 1.3 years). Thirteen children (22%) tolerated all fish tested, including cod, 1 to 14 years (mean, 8.2 ± 4.2 years) following their first reported reaction. Complete fish tolerance increased with age, ranging from 3.4% in preschool children to over 45% in adolescents (95% confidence interval, 26.3%-79.7%). Most children were able to tolerate swordfish (94%) and tuna (95%). Prechallenge specific immunoglobulin E to cod greater than 4.87 kUA/L was the best positive predictive marker for fish allergy persistence (94%), followed by skin prick tests to sardine greater than 6.5 mm (92%).

CONCLUSIONS

A considerable proportion of fish-allergic children develop tolerance around adolescence. Most fish-allergic children can consume tuna and swordfish, which, thus, provide safe alternatives for a balanced diet.

Potential allergenicity of Medicago sativa investigated by a combined IgE-binding inhibition, proteomics and in silico approach

BACKGROUND

Alfalfa (Medicago sativa L) is one of the most planted crops worldwide primarily used to feed animals. The use of alfalfa in human diet as sprouts, infusions and nutritional supplements is rapidly gaining popularity. Despite this, allergenicity assessment of this novel plant food is largely lacking.

RESULTS

Here, leaf protein extract of alfalfa was studied using a combined proteomics, Immunoglobulin E (IgE)-binding inhibition assay and in silico approach to find potential allergens. We have identified and annotated 129 proteins using in-gel digestion proteomics and Blast2Go suit. A search against COMPARE database, using the identified proteins as query sequences, revealed high similarity with several allergenic proteins. The Single Point Highest Inhibition Achievable assay (SPHIAa) performed on the multiplex FABER^® allergy testing system confirmed the in silico results and showed some additional potential allergens. This approach allowed the detection of proteins in alfalfa leaves cross-reacting with plant allergens from three different allergen families such as lipid transfer, thaumatin-like and Bet v 1-like protein families. In addition, the absence of structural determinants cross-reacting with seed storage allergenic proteins and with animal allergens was recorded.

CONCLUSION

This study reports for the first time potential allergenic proteins in alfalfa. The results suggest that this plant food can be safely introduced, as a protein-rich supplement, in the diet of patients allergic to animal food allergens. Allergic patients towards certain plant food allergens need to be careful about consuming alfalfa because they might have allergic symptoms. © 2020 Society of Chemical Industry.

An updated overview of spectrum of gluten-related disorders: clinical and diagnostic aspects

The incidence of gluten-related disorders (GRDs) continues to increase and its global prevalence is estimated at approximately 5% of the population. Celiac disease (CD), dermatitis herpetiformis (DH), gluten ataxia (GA), wheat allergy (WA), and non-celiac gluten sensitivity (NCGS) are the five major GRDs that present with a wide range of clinical manifestations. The diagnosis of GRDs can be challenging because the typical and atypical clinical manifestations of the GRDs overlap. In this review, the current definitions of gluten-related disorders, focusing on their clinical features, diagnostic and therapeutic approaches are presented. We concluded that GRDs are usually diagnosed using a combination of clinical features, serological tests, and histopathological findings. Treatment usually involves dietary modification.

Reduced polyfunctional T cells and increased cellular activation markers in adult allergy patients reporting adverse reactions to food

Background

The underlying cellular mechanisms causing adverse reactions to food are complex and still not fully understood. Therefore, in this study we aimed to identify functional and/or phenotypical immune cell signatures characteristic for adult patients reporting adverse reactions to food.

By mass cytometry, we performed high-dimensional profiling of peripheral blood mononuclear cells (PBMC) from adult patients reporting adverse reactions to food and healthy controls. The patients were grouped according to sIgE-positive or sIgE-negative serology to common food and inhalant allergens. Two broad antibody panels were used, allowing determination of major immune cell populations in PBMC, as well as activation status, proliferation status, and cytokine expression patterns after PMA/ionomycin-stimulation on a single cell level.

Results

By use of data-driven algorithms, several cell populations were identified showing significantly different marker expression between the groups.

Most striking was an impaired frequency and function of polyfunctional CD4+ and CD8+ T cells in patients reporting adverse reactions to food compared to the controls. Further, subpopulations of monocytes, T cells, and B cells had increased expression of functional markers such as CD371, CD69, CD25, CD28, and/or HLA-DR as well as decreased expression of CD23 in the patients. Most of the differing cell subpopulations were similarly altered in the two subgroups of patients.

Conclusion

Our results suggest common immune cell features for both patient subgroups reporting adverse reactions to food, and provide a basis for further studies on mechanistic and diagnostic biomarker studies in food allergy.

Extranasal Manifestations of Allergy in the Head and Neck

PURPOSE OF REVIEW

Allergic rhinitis and allergic asthma are well-described disease entities with broad exposure in clinical and research allergy forums. Associations between allergic inflammation and upper airway diseases of chronic laryngitis, otitis media, obstructive sleep apnea, and oral allergy syndrome are less well understood and described in the literature.

RECENT FINDINGS

This review discusses the relationship between atopy and diseases of the upper airway, oral cavity, larynx, and ear. The similar respiratory mucosal lining the upper aerodigestive tract, with sensitized mast cells and inflammatory mediators in the submucosa, results in a variety of extranasal manifestations of allergic diseases in the head and neck which are less well characterized. Associations between allergic inflammation and upper airway diseases of chronic laryngitis, otitis media, obstructive sleep apnea, and oral allergy syndrome are less well understood and described in the literature. This review will summarize the relevant pathophysiology and symptomology, association with allergic sensitization, and clinical considerations of these disorders.

The Effect of Birch Pollen Immunotherapy on Apple and rMal d 1 Challenges in Adults with Apple Allergy

Background: A proportion of patients allergic to birch pollen are also allergic to pit fruit. The objective of this study was to investigate the effect of immunotherapy with birch pollen on birch-pollen-related apple allergy. Method: Patients with birch pollen immunotherapy underwent a skin-prick test with birch pollen, apple and rMal d 1, global assessments and nasal challenges with birch pollen, open food challenge with apple and a double-blind, placebo-controlled test with rMal d 1 at the start of and during the immunotherapy. Measurements of specific IgE in response to Bet v 1 and rMal d 1 and IgG4 in response to Bet v 1 and rMal d 1 took place. Results: Six of eight patients demonstrated an improvement of nasal challenge test results and all patients improved on global assessment during the immunotherapy. The median oral dose of apple required to elicit a reaction increased but was not statistically significant. The patients showed a decrease in skin-prick test values in response to birch pollen (1.05 to 0.36), apple (0.78 to 0.25) and rMal d 1 (0.51 to 0.10) with p-values of 0.04, 0.03 and 0.06, respectively and a decrease of specific IgE in response to Bet v 1 (10.66 kU/L to 5.19 kU/L) and rMal d 1 (0.99 to 0.61 kU/L) with p-values of 0.01 and 0.05, respectively. Only the median specific IgG4 value to Bet v 1 increased from 0.05 to 1.85 mg/L (p-value of 0.02) and not to IgG4 rMal d 1 (0.07 to 0.08 kU/L). Conclusion: The beneficial effects of immunotherapy for birch pollen were accompanied by a limited effect on apple allergy.

Non-Celiac Gluten Sensitivity in patients with severe abdominal pain and bloating: The accuracy of ALCAT 5

BACKGROUND AND AIMS

Non-Celiac Gluten Sensitivity (NCGS) is a recently proposed clinical condition causing both intestinal and extra-intestinal symptoms, without gastrointestinal lesions, which improve on avoiding gluten intake, in the absence of celiac disease and wheat allergy. The prevalence of this condition is still a matter of debate, in part due to the very recent introduction of an accepted diagnostic test, a double-blind, placebo controlled gluten challenge. However, this is a lengthy and cumbersome procedure, theoretically burdened by a significant reduction of patient compliance. ALCAT 5 is an automated in vitro test evaluating the toxic effect of gluten on neutrophils by the exposure of these cells to a gluten-containing extract of gluten-containing cereals. The test is very simple to perform, the results are rapidly obtained, and might represent, if sufficiently accurate, a promising alternative to diagnose gluten intolerance. The aim of this study was the comparison of ALCAT 5 results with those of a double-blind, placebo-controlled, gluten challenge, in a group of patients with clinically-suspected NCGS.

METHODS

Twenty-five patients (M/F 3/22, mean age 32 ± 4 yrs) with severe functional abdominal pain and bloating, who had previously undergone the ALCAT 5 test, were enrolled. All the subjects reported their symptoms on a gluten-containing diet and considered gluten the causal agent. Following the Salerno Experts' Criteria, they underwent a double-blind, placebo controlled trial with gluten vs placebo. A mean value during gluten ingestion >30% of the value during placebo was considered as indicative of gluten sensitivity.

RESULTS

After blinded administration of gluten, 13 out of 25 (52%) patients showed an increase in the severity of abdominal pain, and 11 out of 25 (44%) showed an increase in the severity of abdominal bloating. Considering these two symptoms together, in 16 patients out of 25 (64%), blinded gluten administration induced an increase of abdominal pain and/or bloating. The ALCAT 5 test proved to be positive in 20 and negative in 5 patients. In sixteen patients out of 25 the result of ALCAT 5 agreed with the double-blind trial (64%). In particular, both tests were positive in 14 patients and negative in 2.

CONCLUSIONS

In this subgroup of patients, ALCAT 5 could be used to support the clinical suspicion of the presence of NCGS and to address these patients to a blinded gluten challenge.

Possible Allergenic Role of Tropomyosin in Patients with Adverse Reactions after Fish Intake

In a recent case report, patient's anti-fish tropomyosin IgE was associated with gastrointestinal symptoms. We aimed to demonstrate on a wider scale that the panallergen tropomyosin should not be limited to invertebrate species and that clinically relevant reactions could be elicited by vertebrate tropomyosin. On the whole, 19 patients with adverse reactions after fish intake and showing negative skin tests with commercial fish extracts were included. Fish tropomyosin was recognized by 10/19 patients' IgE by immunoblotting. All patients with gastrointestinal complaints after fish intake (6/6) showed an IgE band matching with tropomyosin. Cod, albacore, and swordfish tropomyosins were recognized by most patients although 3/10 patients did not claim adverse reactions to these fish species. Immunoblotting with a battery of antigens from different fish species have a high yield of positivity at a band matching with tropomyosin molecular weight, even if they have not been claimed to be causative agents of symptoms. Tropomyosin is therefore a good candidate to be investigated as a clinically relevant fish allergen in patients who report adverse reactions after fish intake.

Pollen-food allergy syndrome is a common allergic comorbidity in adults with eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is associated with atopic diseases including asthma, allergic rhinitis, and atopic dermatitis; however, limited data exist on the correlation between pollen-food allergy syndrome (PFAS) and EoE. We analyzed 346 adults with EoE treated at a single center between 2002 and 2016. Demographic and EoE-specific data including clinical features and measures of EoE disease severity and treatments were collected. The presence of other atopic diseases, family history, prevalence of peripheral eosinophilia and elevated IgE, and details of PFAS triggers were collected. Twenty six percent of the 346 subjects in our cohort had both EoE and PFAS (EoE-PFAS). Compared to subjects with EoE alone, subjects with EoE-PFAS had an increased frequency of allergic rhinitis (86.7% vs. 64.2%, P < 0.001) and family history of allergies (71.1% vs. 53.3%, P = 0.003), and comprised a higher proportion of EoE diagnoses made in the spring (Χ2 < 0.001). 43.3% of subjects with concurrent EoE and PFAS opted for treatment with elimination diet, and these measures failed to induce remission in 46.2% of cases. In most cases, elimination diet failed despite strict avoidance of PFAS trigger foods in addition to common EoE triggers including dairy, wheat, and eggs. EoE-PFAS was also associated with higher serum IgE at the time of EoE diagnosis (460.6 vs. 289.9, P < 0.019). Allergic rhinitis and a family history of food allergy were independently associated with having EoE-PFAS. The most common triggers of PFAS in adults with EoE are apples (21.1%), carrots (15.5%), and peaches (15.5%). Along with asthma, allergic rhinitis and atopic dermatitis, PFAS is a common allergic comorbidity that is highly associated with EoE. Further studies aimed at understanding mechanistic similarities and differences of PFAS and EoE may shed light on the pathogenesis of these closely related food allergy syndromes.

Fructan, Rather Than Gluten, Induces Symptoms in Patients With Self-Reported Non-Celiac Gluten Sensitivity

BACKGROUND & AIMS

Non-celiac gluten sensitivity is characterized by symptom improvement after gluten withdrawal in absence of celiac disease. The mechanisms of non-celiac gluten sensitivity are unclear, and there are no biomarkers for this disorder. Foods with gluten often contain fructans, a type of fermentable oligo-, di-, monosaccharides and polyols. We aimed to investigate the effect of gluten and fructans separately in individuals with self-reported gluten sensitivity.

METHODS

We performed a double-blind crossover challenge of 59 individuals on a self-instituted gluten-free diet, for whom celiac disease had been excluded. The study was performed at Oslo University Hospital in Norway from October 2014 through May 2016. Participants were randomly assigned to groups placed on diets containing gluten (5.7 g), fructans (2.1 g), or placebo, concealed in muesli bars, for 7 days. Following a minimum 7-day washout period (until the symptoms induced by the previous challenge were resolved), participants crossed over into a different group, until they completed all 3 challenges (gluten, fructan, and placebo). Symptoms were measured by Gastrointestinal Symptom Rating Scale Irritable Bowel Syndrome (GSRS-IBS) version. A linear mixed model for analysis was used.

RESULTS

Overall GSRS-IBS scores differed significantly during gluten, fructan, and placebo challenges; mean values were 33.1 ± 13.3, 38.6 ± 12.3, and 34.3 ± 13.9, respectively (P = .04). Mean scores for GSRS-IBS bloating were 9.3 ± 3.5, 11.6 ± 3.5, and 10.1 ± 3.7, respectively, during the gluten, fructan, and placebo challenges (P = .004). The overall GSRS-IBS score for participants consuming fructans was significantly higher than for participants consuming gluten (P = .049), as was the GSRS bloating score (P = .003). Thirteen participants had the highest overall GSRS-IBS score after consuming gluten, 24 had the highest score after consuming fructan, and 22 had the highest score after consuming placebo. There was no difference in GSRS-IBS scores between gluten and placebo groups.

CONCLUSIONS

In a randomized, double-blind, placebo-controlled crossover study of individuals with self-reported non-celiac gluten sensitivity, we found fructans to induce symptoms, measured by the GSRS-IBS. Clinicaltrials.gov no: NCT02464150.

Wheat challenge in self-reported gluten sensitivity: a comparison of scoring methods

BACKGROUND

The condition non-coeliac gluten sensitivity (NCGS) is clinically similar to coeliac disease, but lack objective diagnostic criteria. Symptom relief on gluten-free diet followed by gluten containing food challenge may confirm the condition in clinical settings.

AIM

To describe the results of an open bread challenge in patients with suspected NCGS, and to compare the results with recently suggested cut-offs for symptom change.

MATERIAL AND METHODS

Fifty-six patients (12 males) self-instituted on gluten-free diet with negative coeliac disease diagnostics were examined for NCGS by an open bread challenge. Symptoms were reported by Gastrointestinal Symptom Rating Scale, IBS-version (GSRS-IBS) and visual analogue scale (VAS). Results were retrospectively compared to the Salerno and Monash cut-offs for symptom change.

RESULTS

Forty-seven patients were diagnosed with NCGS. Total GSRS-IBS score and overall symptoms by VAS increased significantly in NCGS (p < .001), but not in non-NCGS patients (p < .12 and p = .08, respectively). Total GSRS-IBS challenge score and overall symptoms by VAS were significantly higher in NCGS than in non-NCGS patients (53 vs. 37, p = .004 and 76 vs. 39 mm, p = .02, respectively). Applying the Salerno and Monash cut-offs, 63 and 75% would be classified with NCGS, respectively. According to total GSRS-IBS absolute agreement was lowest between clinician's diagnosis and Salerno cut-off (63%) and highest between Salerno and Monash cut-offs (88%).

CONCLUSION

Clinician diagnosed 85% with NCGS. The proportion of NCGS was lower according to the Salerno and Monash cut-offs. The Salerno cut-off should be the starting point for a common definition of symptom change.

Standardization of double blind placebo controlled food challenge with soy within a multicentre trial

Background

Multicentre trials investigating food allergies by double blind placebo controlled food challenges (DBPCFC) need standardized procedures, challenge meals and evaluation criteria. We aimed at developing a standardized approach for identifying patients with birch related soy allergy by means of DBPCFC to soy, including determination of threshold levels, in a multicentre setting.

Methods

Microbiologically stable soy challenge meals were composed of protein isolate with consistent Gly m 4 levels. Patients sensitized to main birch allergen Bet v 1 and concomitant sensitization to its soy homologue Gly m 4 underwent DBPCFC. Outcome was defined according to presence and/or absence of ten objective signs and intensity of eight subjective symptoms as measured by visual analogue scale (VAS).

Results

138 adult subjects (63.8% female, mean age 38 years) underwent DBPCFC. Challenge meals and defined evaluation criteria showed good applicability in all centres involved. 45.7% presented with objective signs and 65.2% with subjective symptoms at soy challenge. Placebo challenge meals elicited non-cardiovascular objective signs in 11.6%. In 82 (59.4%) subjects DBPCFC was judged as positive. 70.7% of DPBCFC+ showed objective signs and 85.4% subjective symptoms at soy challenge. Subjective symptoms to soy challenge meal in DBPCFC+ subjects started at significantly lower dose levels than objective signs (p < 0.001). Median cumulative eliciting doses for first objective signs in DBPCFC+ subjects were 4.7 g [0.7–24.7] and 0.7 g [0.2–4.7] total soy protein for first subjective symptoms (p = 0.01).

Conclusions

We present the hitherto largest group of adults with Bet v 1 and Gly m 4 sensitization being investigated by DBPCFC. In this type of food allergy evaluation of DBPCFC outcome should not only include monitoring of objective signs but also scoring of subjective symptoms. Our data may contribute to standardize DBPCFC in pollen-related food allergy in multicentre settings.

Trial registration

EudraCT: 2009-011737-27.

Food Sensitization in Medically Resistant Chronic Rhinosinusitis with or without Nasal Polyposis

BACKGROUND

Nasal polyposis is a common nasal mass with unknown etiology. It has been assumed that allergy predisposes to polyp formation. Our objective was to compare the prevalence of food sensitization in medically resistant chronic rhinosinusitis patients with or without nasal polyposis.

METHODS

One hundred and fifty-five patients who fulfilled the inclusion and exclusion criteria were incorporated into this study. The results of their total serum IgE and food-specific IgE levels were examined.

RESULTS

The average age was 33 years (± 13) with 96 males and 59 females. The percentage of patients in each group that had a positive result for at least one tested allergen was 84% (88 patients in the sinusitis without polyposis group and 42 patients in nasal polyposis group). Patients without nasal polyposis reacted to an average of 4.6 foodstuffs, whereas patients with nasal polyposis reacted to 4.1. Egg white, sheefish and cherry were the most common type of sensitized food. There were no significant differences in the prevalence, type, number of positive food allergens and class level between the two groups.

CONCLUSIONS

Food sensitization is common in medically resistant chronic rhinosinusitis. Since food sensitization prevalence, type and severity do not significantly differ between the two groups studied, food atopy is unlikely to be a major factor in nasal polyposis pathogenesis.

Sensitization profiles to peanut allergens in Belgium; cracking the code in infants, children and adults

OBJECTIVES

Peanut allergy shows distinct clinical patterns that can be predicted by component resolved diagnosis. However, data about peanut sensitization profiles in populations with a broad age stratification are scarce.

METHODS

Sera of 89 peanut allergic patients (age 1-70 years), 21 infants (<1 year) with atopic dermatitis (AD) sensitized to peanut, 24 age matched peanut-tolerant individuals with positive specific IgE (sIgE) to peanut and 15 healthy individuals were tested for sIgE reactivity to rAra h 1, rAra h 2, rAra h 3, rAra h 8, rAra h 9 and rBet v 1 (FEIA ImmunoCAP, Thermo Fisher Scientific).

RESULTS

In infants with AD, Ara h 1, Ara h 2 and Ara h 3 enabled to explain 14/21 (67%) of peanut sensitizations. No sensitization to Ara h 8 or Bet v 1 was observed. Patients with generalized reactions were more frequently sensitized to Ara h 1, Ara h 2 and Ara h 3 compared to patients with an oral allergy syndrome (OAS) and peanut-tolerant patients. Sensitization to Ara h 8 was significantly more observed in patients with an OAS. Ara h 2 showed to be the best marker to distinguish patients with generalized reactions from patients with an OAS and/or peanut sensitized patients but tolerating the legume.

CONCLUSION

Sensitization to Ara h 1, Ara h 2 and Ara h 3 can have an early onset and is predominantly associated with a more severe outcome. Ara h 2 is the best marker of a generalized peanut allergy.

Randomised clinical study: gluten challenge induces symptom recurrence in only a minority of patients who meet clinical criteria for non-coeliac gluten sensitivity

BACKGROUND

It is unknown whether symptoms in non-coeliac patients (non-CD) meeting clinical diagnostic criteria for noncoeliac gluten sensitivity (NCGS) are specifically triggered by gluten.

AIM

To assess gluten sensitivity in patients diagnosed with NCGS.

METHODS

We studied 35 non-CD subjects (31 females) that were on a gluten-free diet (GFD), in a double-blind challenge study. Participants were randomised to receive either gluten-containing flour or gluten-free flour for 10 days, followed by a 2-week washout period and were then crossed over. The main outcome measure was their ability to identify which flour contained gluten. Secondary outcome measures were based upon Gastrointestinal Symptoms Rating Scale (GSRS) scores.

RESULTS

The gluten-containing flour was correctly identified by 12 participants (34%), who were classified as having NCGS. Their mean GSRS dimension scores were significantly higher following gluten challenge compared to baseline. The scores were: pain, 1.7 ± 0.8 vs. 2.6 ± 1.0; reflux, 1.6 ± 0.5 vs. 2.2 ± 0.9; indigestion, 1.9 ± 0.7 vs. 3.2 ± 1.1; diarrhoea, 1.6 ± 0.7 vs. 2.9 ± 1.5 and constipation, 1.9 ± 0.9 vs. 2.9 ± 1.3. Seventeen participants (49%) erroneously considered the gluten-free flour to contain gluten. Their mean GSRS dimension scores were significantly higher following gluten-free flour challenge compared to baseline. The scores were: pain, 1.6 ± 0.9 vs. 3.0 ± 0.9; reflux, 1.4 ± 0.5 vs. 2.3 ± 1.1; indigestion, 2.0 ± 1.1 vs. 3.7 ± 1.1; diarrhoea, 1.6 ± 0.7 vs. 3.0 ± 1.2 and constipation, 1.6 ± 0.9 vs. 2.6 ± 1.3. The other six participants (17%) were unable to distinguish between the flours.

CONCLUSION

Double-blind gluten challenge induces symptom recurrence in just one-third of patients fulfilling the clinical diagnostic criteria for non-coeliac gluten sensitivity.

Food allergy in the Netherlands: differences in clinical severity, causative foods, sensitization and DBPCFC between community and outpatients

BACKGROUND

It is unknown whether food allergy (FA) in an unselected population is comparable to those from an outpatient clinic population.

OBJECTIVE

To discover if FA in a random sample from the Dutch community is comparable to that of outpatients.

METHODS

This study was part of the Europrevall-project. A random sample of 6600 adults received a questionnaire. Those with symptoms to one of 24 defined priority foods were tested for sIgE. Participants with a positive case history and elevated sIgE were evaluated by double-blind placebo-controlled food challenge (DBPCFC). Outpatients with a suspicion of FA were evaluated by questionnaire, sIgE and DBPCFC.

RESULTS

In the community, severe symptoms were reported less often than in outpatients (39.3% vs. 54.3%). Participants in the community were less commonly sensitized to any of the foods. When selecting only those with a probable FA (i.e. symptoms of priority food and elevation of sIgE to the respective food), no major differences were observed with respect to severity, causative foods, sensitization and DBPCFC between the groups.

CONCLUSION

In the Netherlands, there are large differences in self-reported FA between community and outpatients. However, Dutch community and outpatients with a probable FA do not differ with respect to severity, causative foods, sensitization and DBPCFC-outcome.

IgE, IgG4 and IgA specific to Bet v 1-related food allergens do not predict oral allergy syndrome

BACKGROUND

Birch pollen-associated plant food allergy is caused by Bet v 1-specific IgE, but presence of cross-reactive IgE to related allergens does not predict food allergy. The role of other immunoglobulin isotypes in the birch pollen-plant food syndrome has not been investigated in detail.

METHODS

Bet v 1-sensitized birch pollen-allergic patients (n = 35) were diagnosed for food allergy by standardized interviews, skin prick tests, prick-to-prick tests and ImmunoCAP. Concentrations of allergen-specific IgE, IgG1, IgG4 and IgA to seven Bet v 1-related food allergens were determined by ELISA.

RESULTS

Bet v 1, Cor a 1, Mal d 1 and Pru p 1 bound IgE from all and IgG4 and IgA from the majority of sera. Immunoglobulins to Gly m 4, Vig r 1 and Api g 1.01 were detected in <65% of the sera. No significant correlation was observed between plant food allergy and increased or reduced levels of IgE, IgG1, IgG4 or IgA specific to most Bet v 1-related allergens. Api g 1-specific IgE was significantly (P = 0.01) elevated in celeriac-allergic compared with celeriac-tolerant patients. Likewise, frequencies of IgE (71% vs 15%; P = 0.01) and IgA (86% vs 38%; P = 0.04) binding to Api g 1.01 were increased.

CONCLUSION

Measurements of allergen-specific immunoglobulins are not suitable for diagnosing Bet v 1-mediated plant food allergy to hazelnut and Rosaceae fruits. In contrast, IgE and IgA to the distantly related allergen Api g 1 correlate with allergy to celeriac.

Diagnosis and management of food allergies: new and emerging options: a systematic review

It is reported that 6% of children and 3% of adults have food allergies, with studies suggesting increased prevalence worldwide over the last few decades. Despite this, our diagnostic capabilities and techniques for managing patients with food allergies remain limited. We have conducted a systematic review of literature published within the last 5 years on the diagnosis and management of food allergies. While the gold standard for diagnosis remains the double-blind, placebo-controlled food challenge, this assessment is resource intensive and impractical in most clinical situations. In an effort to reduce the need for the double-blind, placebo-controlled food challenge, several risk-stratifying tests are employed, namely skin prick testing, measurement of serum-specific immunoglobulin E levels, component testing, and open food challenges. Management of food allergies typically involves allergen avoidance and carrying an epinephrine autoinjector. Clinical research trials of oral immunotherapy for some foods, including peanut, milk, egg, and peach, are under way. While oral immunotherapy is promising, its readiness for clinical application is controversial. In this review, we assess the latest studies published on the above diagnostic and management modalities, as well as novel strategies in the diagnosis and management of food allergy.

Lactose malabsorption and intolerance: pathogenesis, diagnosis and treatment

Lactose malabsorption is a common condition caused by reduced expression or activity of lactase in the small intestine. In such patients, lactose intolerance is characterized by abdominal symptoms (e.g. nausea, bloating, and pain) after ingestion of dairy products. The genetic basis of lactose malabsorption is established and several tests for this condition are available, including genetic, endoscopic, and H2-breath tests. In contrast, lactose intolerance is less well understood. Recent studies show that the risk of symptoms after lactose ingestion depends on the dose of lactose, lactase expression, intestinal flora, and sensitivity of the gastrointestinal tract. Lactose intolerance has recently been defined as symptoms developing after ingestion of lactose which do not develop after placebo challenge in a person with lactose maldigestion. Such blinded testing might be especially important in those with functional gastrointestinal diseases in whom self-reported lactose intolerance is common. However, placebo-controlled testing is not part of current clinical practice. Updated protocols and high-quality outcome studies are needed. Treatment options of lactose intolerance include lactose-reduced diet and enzyme replacement. Documenting the response to multiple doses can guide rational dietary management; however, the clinical utility of this strategy has not been tested. This review summarizes the genetic basis, diagnosis, and treatment of lactose malabsorption and intolerance.

Polyvinylpyrrolidone microneedles enable delivery of intact proteins for diagnostic and therapeutic applications

We present a method of fabricating microneedles from polyvinylpyrrolidone (PVP) that enables delivery of intact proteins (or peptides) to the dermal layers of the skin. PVP is known to self-assemble into branched hollow fibers in aqueous and alcoholic solutions; we utilized this property to develop dissolvable patches of microneedles. Proteins were dissolved in concentrated PVP solution in both alcohol and water, poured into polydimethylsiloxane templates shaped as microneedles and, upon evaporation of solvent, formed into concentric, fibrous, layered structures. This approach of making PVP microneedles overcomes problems in dosage, uniform delivery and stability of protein formulation as compared to protein-coated metallic microneedles or photopolymerized PVP microneedles. Here we characterize the PVP microneedles and measure the delivery of proteins into skin. We show that our method of fabrication preserves the protein conformation. These microneedles can serve as a broadly useful platform for delivering protein antigens and therapeutic proteins to the skin, for example for allergen skin testing or immunotherapy.

Design of clinical trials evaluating dietary interventions in patients with functional gastrointestinal disorders

Clear guiding principles for the design and conduct of dietary intervention trials in functional gastrointestinal disorders (FGID) are lacking. This narrative review examines the specific challenges associated with the design and reporting in dietary intervention trials. Dietary intervention trials need to address the collinearity between food, nutrients, and bioactive components that obscure the relationship between food and their effects in the gut. Randomized, double-blinded, placebo-controlled studies remain the gold standard for dietary trials, but are limited by difficulties in adequate masking of study food or inappropriate choice of placebo food/diets. Provision of study diets as the preferred delivery method can somewhat address these limitations, although allowing good adherence compared with education-based dietary interventions. Issues associated with participant expectancies and dietary behaviors can alter the true effectiveness of a diet. In addition, failure to adjust for or report baseline intake of nutrients of interest can reduce their magnitude of benefit. Bias in subjective reports and choice of measurement tools can preclude accurate assessment of food-intake data. In the design of elimination and rechallenge studies, sufficient time period and adequate exclusion of dietary triggers are essential to ensure symptoms are well-controlled before rechallenging. The route and frequency of challenging, design of test food, and/or placebo should match the aims of the rechallenge phase. Long-term efficacy data of such therapeutic diets has been poorly documented in most studies. Standardized guidelines that address many of the challenges outlined above are suggested to strengthen the quality of evidence for dietary therapies in FGID.

Asthmatic response to milk ingestion challenge in adults: a comparison of the open and double-blind challenges

BACKGROUND

Cow's milk allergy can participate in pathophysiological mechanisms underlying bronchial asthma in some adult patients. This role should ultimately be confirmed by means of a milk ingestion challenge. In this study, the diagnostic value of the open food ingestion challenge (OFICH) and the double-blind placebo-controlled food challenge (DBPCFC) techniques with milk were compared in adult patients suffering from bronchial asthma with suspected milk allergy.

METHODS

In 87 asthmatics with a suspected history and positive skin tests for milk, the 87 OFICHs and DBPCFCs were performed in combination with spirometry and followed up to 72 h after the challenge.

RESULTS

Of 87 patients, 74 (85%) developed a positive asthmatic response (AR) (20 immediate, 33 late, 6 dual late and 15 delayed; p < 0.01) and 13 (15%) developed a negative AR (p > 0.1) to OFICH. Seventy-five (86%) developed a positive AR (17 immediate, 35 late, 8 dual late and 15 delayed; p < 0.01) and 12 (14%) developed a negative AR (p > 0.05) to DBPCFC. The correlation between the OFICH and DBPCFC was statistically significant (p < 0.01). All placebo control challenges were negative (p > 0.2).

CONCLUSIONS

In some adults with bronchial asthma, involvement of an allergy to cow's milk results in the appearance of various AR types (immediate, late, dual late or delayed). The milk allergy can be confirmed by open or double-blind techniques, combined with spirometry. No significant differences were found between the OFICH and DBPCFC results. OFICH with natural milk combined with spirometry seems, therefore, to be an adequate technique for the detection of milk allergy in asthmatics. The DBPCFC can be performed as an additional check, if necessary.

Non-celiac gluten sensitivity

Gluten sensitivity has been best recognized and understood in the context of two conditions, celiac disease and wheat allergy. However, some individuals complain of symptoms in response to ingestion of "gluten," without histologic or serologic evidence of celiac disease or wheat allergy. The term non-celiac gluten sensitivity (NCGS) has been suggested for this condition, although a role for gluten proteins as the sole trigger of the associated symptoms remains to be established. This article reviews the available information regarding symptomatology, epidemiology and genetics, serology and histology, and in vitro and in vivo experimental data on the pathophysiology of NCGS.

Colonoscopic allergen provocation test with rBet v 1 in patients with pollen-associated food allergy

BACKGROUND

After consumption of fruits, nuts, and vegetables, several patients with pollen allergy experience gastrointestinal (GI) tract symptoms that are possibly caused by pollen-associated food allergy. The aim of this study was to evaluate the colonoscopic allergen provocation (COLAP) test using the recombinant birch pollen allergen Bet v 1 (rBet v 1) for in vivo diagnosis of pollen-associated food allergy manifesting in the GI tract.

METHODS

Thirty-four patients with a history of adverse reactions to food, GI tract symptoms, and birch pollen pollinosis and five healthy controls underwent COLAP test. Twenty minutes after endoscopic challenge of the cecal mucosa with rBet v 1, the mucosal wheal and flare reaction was registered semiquantitatively, and tissue biopsy specimens were examined for eosinophil mucosal activation.

RESULTS

The mucosal reaction to rBet v 1 was correlated with the presence of pollinosis (P = 0.004), history of adverse reaction to Bet v 1-associated food allergens (P = 0.001), and tissue eosinophils' activation (P < 0.001). A wheal and flare reaction in the COLAP test was observed in 13 of 16 patients (81%) with a history of GI tract symptoms associated with the ingestion of Bet v 1-related foods and in four of 18 (22%) patients with a negative history (P < 0.001). The control group did not develop visible mucosal reactions to rBet v 1. Systemic anaphylactic reactions did not occur.

CONCLUSIONS

The mucosal administration of rBet v 1 by COLAP test provides a new diagnostic tool that might support the diagnosis of Bet v 1-associated food allergy manifesting in the GI tract.

Kidney bean: a major sensitizer among legumes in asthma and rhinitis patients from India

Background

The prevalence of IgE mediated food allergies has increased over the last two decades. Food allergy has been reported to be fatal in highly sensitive individuals. Legumes are important food allergens but their prevalence may vary among different populations. The present study identifies sensitization to common legumes among Indian population, characterizes allergens of kidney bean and establishes its cross reactivity with other legumes.

Methodology

Patients (n = 355) with history of legume allergy were skin prick tested (SPT) with 10 legumes. Specific IgE (sIgE) and total IgE were estimated in sera by enzyme-linked immunosorbent assay. Characterization of kidney bean allergens and their cross reactivity was investigated by immunobiochemical methods. Identification of major allergens of kidney bean was carried out by mass spectrometry.

Principal Findings

Kidney bean exhibited sensitization in 78 (22.0%) patients followed by chickpea 65 (18.0%) and peanut 53 (15%). SPT positive patients depicted significantly elevated sIgE levels against different legumes (r = 0.85, p<0.0001). Sera from 30 kidney bean sensitive individuals exhibited basophil histamine release (16–54%) which significantly correlated with their SPT (r = 0.83, p<0.0001) and sIgE (r = 0.99, p<0.0001). Kidney bean showed eight major allergens of 58, 50, 45, 42, 40, 37, 34 and 18 kDa on immunoblot and required 67.3±2.51 ng of homologous protein for 50% IgE inhibition. Inhibition assays revealed extensive cross reactivity among kidney bean, peanut, black gram and pigeon pea. nLC-MS/MS analysis identified four allergens of kidney bean showing significant matches with known proteins namely lectin (phytohemagglutinin), phaseolin, alpha-amylase inhibitor precursor and group 3 late embryogenesis abundant protein.

Conclusion/Significance

Among legumes, kidney bean followed by chick pea and peanut are the major allergic triggers in asthma and rhinitis patients in India. Kidney bean showed eight major allergens and cross reacted with other legumes. A combination of SPT, sIgE and histamine release assay is helpful in allergy diagnosis.

Late type of bronchial response to milk ingestion challenge: a comparison of open and double-blind challenge

Background. In some asthmatics the food allergy, for example, to milk, can participate in their bronchial complaints. The role of food allergy should be confirmed definitively by food ingestion challenge performed by an open challenge with natural foods (OFICH) or by a double-blind placebo-controlled food challenge (DBPCFC). Objectives. To investigate the diagnostic value of these techniques for confirmation of a suspected milk allergy in bronchial asthma patients. Methods. In 54 asthmatics with a positive history and/or positive skin tests for milk the 54 OFICH, and DBPCFC, were performed in combination with spirometry. Results. The 54 patients developed 39 positive late asthmatic responses (LAR) and 15 negative asthmatic responses to OFICH and 40 positive LARs and 14 negative responses to DBPCFC. The overall correlation between the OFICH and DBPCFC was statistically significant (P < 0.01). Conclusions. This study has confirmed the existence of LAR to milk ingestion performed by OFICH and DBPCFC in combination with spirometry. The results obtained by both the techniques did not differ significantly. The OFICH with natural food combined with monitoring of objective parameter(s), such as spirometry, seems to be a suitable method for detection of the food allergy in asthmatics. The DBPCFC can be performed as an additional check, if necessary.