The usefulness of casein-specific IgE and IgG4 antibodies in cow's milk allergic children

• Main Authors: Ito Komei, Futamura Masaki, Movérare Robert, Tanaka Akira, Kawabe Tsutomu, Sakamoto Tatsuo, Borres Magnus P
• Format: Article
• Language: English
• Published: BMC 2012-01-01
• Series: Clinical and Molecular Allergy
• Subjects: casein; cow's milk allergy; IgE; IgG4; ImmunoCAP
• Online Access: http://www.clinicalmolecularallergy.com/content/10/1/1

<p>Abstract</p> <p>Background</p> <p>Cow's milk allergy is one of the most common food allergies among younger children. We investigated IgE antibodies to milk, and IgE and IgG4 antibodies to casein, α-lactalbumin and β-lactoglobulin in cow's milk allergic (CMA) and non-allergic (non-CMA) children in order to study their clinical usefulness.</p> <p>Methods</p> <p>Eighty-three children with suspected milk allergy (median age: 3.5 years, range: 0.8-15.8 years) were diagnosed as CMA (n = 61) or non-CMA (n = 22) based on an open milk challenge or convincing clinical history. Their serum concentrations of allergen-specific (s) IgE and IgG4 antibodies were measured using ImmunoCAP^®. For the sIgG4 analysis, 28 atopic and 31 non-atopic control children were additionally included (all non-milk sensitized).</p> <p>Results</p> <p>The CMA group had significantly higher levels of milk-, casein- and β-lactoglobulin-sIgE antibodies as compared to the non-CMA group. The casein test showed the best discriminating performance with a clinical decision point of 6.6 kU_A/L corresponding to 100% specificity. All but one of the CMA children aged > 5 years had casein-sIgE levels > 6.6 kU_A/L. The non-CMA group had significantly higher sIgG4 levels against all three milk allergens compared to the CMA group. This was most pronounced for casein-sIgG4 in non-CMA children without history of previous milk allergy. These children had significantly higher casein-sIgG4 levels compared to any other group, including the non-milk sensitized control children.</p> <p>Conclusions</p> <p>High levels of casein-sIgE antibodies are strongly associated with milk allergy in children and might be associated with prolonged allergy. Elevated casein-sIgG4 levels in milk-sensitized individuals on normal diet indicate a modified Th2 response. However, the protective role of IgG4 antibodies in milk allergy is unclear.</p>