Allergenicity and safety of recombinant human C1 esterase inhibitor in patients with allergy to rabbit or cow's milk.

BACKGROUND: Recombinant human C1 inhibitor (rhC1INH) for on-demand treatment of hereditary angioedema is purified from milk of transgenic rabbits. It contains low amounts (<0.002%) of host-related impurities, which could trigger hypersensitivity reactions in patients with rabbit allergy (RA) and/or cow's milk allergy (CMA). OBJECTIVE: This study is an assessment of allergenicity and safety of rhC1INH in patients with RA and/or CMA. METHODS: Patients with CMA and/or RA underwent skin prick test (SPT), intracutaneous test (ICT), and, when results for both were negative, subcutaneous (SC) challenge with up to 2100U (14 mL) rhC1INH. The negative predictive value of the skin test protocol was calculated, defined as the ratio of patients without systemic symptoms of hypersensitivity following SC challenge, over the number of patients having tested negative for both the SPT and the ICT. Adverse events after exposure to rhC1INH were recorded. RESULTS: Twenty-six patients with RA and/or CMA were enrolled. Twenty-four had negative SPT and ICT results for rhC1INH, whereas 2 had negative SPT result but positive ICT result to rhC1INH (only the highest concentration). Twenty-two patients with negative SPT and ICT results underwent SC challenge. None developed allergic symptoms. Local treatment-emergent adverse events occurred in 7 patients (32%) after SC challenge. In 5 these were considered drug related. All were mild. CONCLUSIONS: None of the patients with negative SPT and ICT results for rhC1INH had allergic symptoms during rhC1INH challenge. The negative predictive value of the combination of SPT and ICT for the outcome of the SC challenge was 100% (95% CI, 84.6%-100%). SC administration of rhC1INH was well tolerated.

Characterization of T cell epitopes in bovine α-lactalbumin.

BACKGROUND: Recent studies have indicated that peptides containing T cell epitopes may be used for immunotherapy. While for several cow's milk allergens the T cell epitopes have been described, the T cell epitopes in the major allergen α-lactalbumin (α-LAC) are unknown. Therefore, the aim of this study was to determine the T cell epitopes in α-LAC. METHODS: Nineteen synthetic peptides spanning α-LAC were obtained. Cow's milk-specific T cell lines (TCLs) of 46 subjects were generated and tested for their specificity for α-LAC. The lines responding to α-LAC were subsequently tested to determine their activation in response to the peptides. RESULTS: More than half of the TCLs generated did not respond to α-LAC or lost their responsiveness during subsequent experiments, which indicates that α-LAC has low immunogenicity. Only 8 TCLs recognized 1 or more peptides. The recognition of the peptides was diverse and no major epitopes could be defined. CONCLUSION: The immunogenicity of α-LAC is very low compared to other major allergens in cow's milk. Moreover, there seems to be no dominant epitope present in the protein. Therefore, it seems unlikely that peptides of this protein can be used for immunotherapy.

Quality of life is more impaired in patients seeking medical care for food allergy.

BACKGROUND: Food allergy (FA) affects 2-4% of adults, but only a small percentage visit an outpatient clinic for a thorough evaluation. METHODS: A matched case-control study was used to compare health-related quality of life (HRQL) of the Dutch general population that did not seek medical care for their FA with outpatients who did seek medical care. All participants were diagnosed as food allergic (i.e. with a suggestive history and corresponding positive IgE). HRQL was measured using the Food Allergy Quality of Life Questionnaire--Adult Form (FAQLQ-AF). A food allergy independent measure (FAIM) was used to evaluate the adult's perception of the severity of his/her disease. RESULTS: Total FAQLQ-AF score in individuals who never visited a doctor for their FA was significantly lower than that of patients who sought medical care (2.4 vs. 3.9, p = 0.03), indicating that the former had a better quality of life than patients who did seek medical care. Regarding the different domains of FAQLQ, the score for allergen avoidance and dietary restrictions and the score for emotional impact (EI) was significantly higher in the group that sought medical care (p = 0.02 and 0.03, respectively), indicating the importance of these domains. The FAIM score was significantly higher in the group that sought medical care, indicating that they perceived their FA as more severe. CONCLUSION AND CLINICAL RELEVANCE: Patients who seek medical care for their FA have a more impaired HRQL and perceive their FA as more severe. Food avoidance and issues related to the EI of FA are key areas of intervention aimed at improving HRQL in patients with FA.

Food Allergy in Adults: Substantial Variation in Prevalence and Causative Foods Across Europe.

BACKGROUND: According to the community-based EuroPrevall surveys, prevalence of self-reported food allergy (FA) in adults across Europe ranges from 2% to 37% for any food and 1% to 19% for 24 selected foods. OBJECTIVE: To determine the prevalence of probable FA (symptoms plus specific IgE-sensitization) and challenge-confirmed FA in European adults, along with symptoms and causative foods. METHODS: In phase I of the EuroPrevall project, a screening questionnaire was sent to a random sample of the general adult population in 8 European centers. Phase II consisted of an extensive questionnaire on reactions to 24 preselected commonly implicated foods, and measurement of specific IgE levels. Multiple imputation was performed to estimate missing symptom and serology information for nonresponders. In the final phase, subjects with probable FA were invited for double-blind placebo-controlled food challenge. RESULTS: Prevalence of probable FA in adults in Athens, Reykjavik, Utrecht, Lodz, Madrid, and Zurich was respectively 0.3%, 1.4%, 2.1%, 2.8%, 3.3%, and 5.6%. Oral allergy symptoms were reported most frequently (81.6%), followed by skin symptoms (38.2%) and rhinoconjunctivitis (29.5%). Hazelnut, peach, and apple were the most common causative foods in Lodz, Utrecht, and Zurich. Peach was also among the top 3 causative foods in Athens and Madrid. Shrimp and fish allergies were relatively common in Madrid and Reykjavik. Of the 55 food challenges performed, 72.8% were classified as positive. CONCLUSIONS: FA shows substantial geographical variation in prevalence and causative foods across Europe. Although probable FA is less common than self-reported FA, prevalence still reaches almost 6% in parts of Europe.