The Most Common Cow's Milk Allergenic Proteins with Respect to Allergic Symptoms in Iranian Patients

Cow's milk allergy (CMA) is an immunological response to cow's milk proteins such as casein, α-lactalbumin and β lactoglobulin. The aim of this study was to determine the most common cow's milk allergenic proteins in patients with CMA and identify the most effective proteins in different allergic symptoms. Eighty seven patients (≤18 years) with allergy to cow's milk from 2006 to 2013 entered this study. They had a positive history of allergic reactions to cow's milk and a positive specific IgE test to whole cow's milk. The patients' symptoms were divided into four groups. Serum specific IgEs against four different main proteins of cow's milk were measured using RIDA Allergy Screen. Among 87 patients, 53 (60.5%) were male and the median age was 2.5 years. The frequency of respiratory, skin, gastrointestinal symptoms, and anaphylaxis were 63.3%, 55.7%, 20.3%, and 13.4%, respectively. Specific IgEs to total cow's milk protein (n=75, 89.3%), and the main Cow's Milk Proteins including α-lactalbumin (n=65, 77.4%), casein (n=64, 75.3%), β-lactoglobulin (n=52, 62.7%), and bovine serum albumin (n=35, 44.9%) were detected. Specific IgE tests to β-lactoglobulin were positive in 90% of the patients with anaphylaxis. Moreover, significant relationship was found between specific IgE to β-lactoglobulin and anaphylaxis (p=0.04). Although it is presumed that α-lactalbumin and casein are the most common allergenic proteins of cow's milk, in this study there is a significant relationship between the anaphylaxis and the presence of β-lactoglobulin-specific IgE. Therefore, more precautions are recommended due to possible anaphylactic reactions in patients with a positive test history for β-lactoglobulin specific IgE.