Food oral immunotherapy: Any distinguishing factors predicting the need of anti-IgE?

Oral immunotherapy (OIT) has gained popularity recently for IgE-mediated food allergy. Omalizumab (OMZ) has been used in patients (10-20%) who have too severe/frequent allergic reactions (AR) to continue OIT, to reduce these reactions. In this study, it was aimed to compare two groups of patients who completed OIT with and without OMZ and to seek determinants predicting the need of this treatment. It was also aimed to share the clinical findings regarding the long-term use of OMZ and the withdrawal process. Forty-one patients were started OIT and 93% could be desensitized. Two groups were similar in means of demographic characteristics, and clinical and laboratory findings. The patients who needed OMZ during OIT had also lower reaction doses during oral challenge (p = 0.037). Higher AR rate in this group declined after starting OMZ (p < 0.001). The injection intervals of OMZ were gradually extended. Most patients were able to discontinue OMZ (81%). There were no severe reactions during drug withdrawal attempts. The low reaction thresholds during oral food challenge may give a clue about OMZ requirement during OIT. It may be an option to start the treatment before OIT if reaction was seen in the first few steps of the oral food challenge. For the sake of safety, extension of injection intervals should be preferred instead of abruptly stopping OMZ.

The psychological impact of food allergy and undergoing a food challenge test in adult age

Summary

Introduction. Despite an increasing number of adults being affected by food allergy, there is currently limited research regarding the psychological impact of living with this condition in this age group and the effect of undergoing food challenge testing - the gold standard for diagnosis - on health-related quality of life (HRQoL). Objective. To assess whether ruling out a food allergy using an open food challenge could improve HRQoL and emotional well-being. To evaluate whether HRQoL gains are higher among people testing negative for food allergy and whether people higher on health anxiety would be less reassured by a negative food challenge. Methods. A cross-sectional study (n = 276) and a prospective study (n = 53) were performed. Adults with a positive (n = 34), or negative food challenge (n = 34), or with an allergy confirmed via other means (No challenge, n = 208), completed the Food Allergy Quality of Life Questionnaire-Adult Form, General Health Questionnaire-12, State-Trait Anxiety Inventory short form, Positive and Negative Affect Schedule, shortened version of the Health Anxiety Questionnaire in addition to clinical and demographic variables. A prospective study examined these measures before and three months after a food challenge (negative, n = 45; positive, n = 8). Results. Adults with a negative food challenge outcome had better HRQoL than those with a food allergy confirmed via other means (No challenge), with no differences between the two allergy positive groups (food challenge vs no challenge). No group differences in emotional distress, health anxiety or mood were found. The prospective study showed HRQoL significantly improved following a food challenge (F_(1,39) = 16.868; p minor 0.001; Intention-to-treat F_(1,52) = 15.346; p minor 0.001). High health anxiety was not associated with lower reassurance following a negative test. Conclusions. People who have a food allergy excluded following a food challenge have better HRQoL. There was a significant improvement in HRQoL following an open food challenge which supports the need to increase provision of food challenge testing in this age group.

Role of atopy patch test for diagnosis of food allergy-related gastrointestinal symptoms in children

BACKGROUND

Double-blind, placebo-controlled food challenge is the gold standard for diagnosing food allergy. However, it is a time-consuming procedure and requires onsite medical supervision and resuscitating medicines and devices on hand. The objective of this study was to compare the atopy patch test (APT) with the oral food challenge test (OFC) in children with suspected food allergy-related gastrointestinal (GI) symptoms.

METHODS

A prospective self-controlled study enrolled children with a history of suspected food allergy-related GI symptoms. Skin prick test (SPT) and APT using lyophilized and commercial allergen extracts for cow's milk, egg, wheat, soy, and shrimp were evaluated, and OFC was performed.

RESULTS

Thirty-nine patients (25 boys, median age 2.4 yrs) with 76 events of suspected food allergy-related GI symptoms were enrolled. SPT was positive in 11/76 events (14.5%). Sensitivity, specificity, predictive values, and likelihood ratio were calculated related to the food challenge outcome. Of 41 OFC, 30 (73.2%) were positive. APT using lyophilized allergen extracts yielded high sensitivity (80%) and high positive predictive value (85.7%). APT using commercial allergen extracts yielded low sensitivity (30%) but high specificity (90%). The negative predictive value of APT using lyophilized and commercial allergen extracts was 53.8% and 32.2%, respectively. All cases with positive APT using lyophilized allergen extracts together with positive SPT also had positive OFC.

CONCLUSION

In contrast to commercial extracts, APT with lyophilized allergen extracts is reliable, safe, and maybe useful for the diagnosis of suspected food allergy-related GI symptoms in children. OFC is still needed in most of the cases.

Profilin as a severe food allergen in allergic patients overexposed to grass pollen

BACKGROUND

Profilins are ubiquitous proteins that act as panallergens in sensitized patients, considered to be mild or incomplete food allergens. The aim of the study was to evaluate the role of profilins as severe food allergens in allergic patients overexposed to grass who were referred for severe food reactions and were sensitized to profilins.

METHODS

After a careful in vitro screening, 26 patients were included, classified into two groups, mild (17) and severe reactors (9), based on clinical history and subsequently provoked orally with purified profilin in a double-blind placebo-controlled food challenge setup.

RESULTS

A significant number of patients presented severe positive food challenge test reactions at low doses of the allergen profilin. Patients prone to suffer from severe reactions had lower IgG4/IgE ratio to major grass allergens than those who did not.

CONCLUSION

Profilins are complete food allergens in food-allergic patient populations that are exposed to high levels of grass pollen. This type of patient constitutes an optimal model to understand the link between respiratory and food allergies. The nature of the observed reactions and the low level of allergen eliciting the reactions suggest that intake through the oral mucosa might constitute a relevant route of exposure to food allergens.