Tolerance to a New Free Amino Acid-based Formula in Children With IgE or Non-IgE-mediated Cow's Milk Allergy

Prospective controlled study including pediatric patients (≤14 years of age) with a recent diagnosis of IgE- or non-IgE-mediated CMA, confirmed by positive oral food challenge or anaphylaxis in the 2 months prior to enrollment and under good clinical control. Children with concomitant chronic systemic diseases, congenital cardiac defects, active tuberculosis, autoimmune diseases, immunodeficiency, chronic inflammatory bowel diseases, celiac disease, cystic fibrosis, metabolic diseases, lactose intolerance, malignancy, chronic pulmonary diseases, malformations of the gastrointestinal tract, gastroesophageal reflux disease non-food allergy-related, suspected eosinophilic gastrointestinal disorders, were excluded. At the first evaluation, the clinical history, information on allergic disease and baseline clinical conditions were assessed by 3 experienced pediatric allergists and the child was invited to participate in the study. At least one parent of each subject provided written informed consent. Children with atopic dermatitis were included if it was under sufficient control to allow recognition of a positive response to the challenge. Infants and children using a betablocker within 12 hours of the challenge, and short-acting, medium-acting, or long-acting antihistamines more than once within 3, 7, or 21 days of DBPCFC, respectively, or oral steroids within 21 days of oral food challenge were excluded from study. Adverse events were recorded throughout the study.

Food allergy screening tests Measurement of serum specific IgE against CMP (alpha-lactalbumin, ALA; beta-lactoglobulin, BLG; and casein); skin prick tests (SPT) with whole milk, CMP, placebo formula (another commercially available Aaf, Neocate, Nutricia, Milan, Italy) and study formula (Sineall, Humana, Milan, Italy); and atopy patch tests (APT) with whole milk, placebo and study formula, were performed on all patients.

Serum samples from patients were analysed for specific IgE antibody titers against CMP using a commercially available kit (CAP-RAST, Pharmacia Diagnostics AB, Uppsala Sweden). The detection limit of the system was 0.35 kU/L IgE. Subjects were deemed sensitised if their specific IgE levels exceeded the detection limit.

Skin prick tests were performed using a 1-mm single peak lancet (ALK, Copenhagen, Denmark), with histamine dihydrochloride (10 mg/ml) and isotonic saline solution (NaCl 0.9%) as positive and negative control, respectively. Reactions were recorded on the basis of the largest diameter (in millimetres) of the wheal and flare at 15 min. The SPT result were considered "positive" if the wheal was 3 mm or larger, without reaction of the negative control.

Atopy patch tests were performed as previously reported. Briefly, we used 1 drop (50 μl) of fresh milk put on filter paper and applied with adhesive tape to the unaffected skin of the child's back, using 12-mm aluminium cups (Finn Chambers on Scan pore; Epitest Ltd Oy, Tuusula, Finland). Isotonic saline solution was the negative control. The occlusion time was 48 h and results were read 20 min and 24 h after removal of the cups. To exclude false positive reactions, we also tested allergens in a 1:10 solution. Seventy-two hours after the start of the test, reactions were classified as follows: - negative; +/- doubtful: erythema only; + weak positive: erythema, slight infiltration, papules; ++ strong positive: erythema, infiltration, papules, little vesicles; +++ very strong positive: erythema, large confluent vesicles in bubbles. Children and their families were requested to report any delayed skin reaction that was noticed after this time. Irritant or doubtful reactions, including sharply demarcated confluent erythema, or reactions confined to margins without infiltration, were deemed negative.