Serum immunoglobulin E, IgA, and IgG antibodies to different cow's milk proteins in children with cow's milk allergy: Association with prognosis and clinical manifestations

Diverse pathogenic mechanisms elicit different clinical manifestations in cow's milk allergy (CMA). Our aim was to determine the concentration of serum immunoglobulin levels to different cow's milk proteins in patients with CMA and to determine how these values were related to clinical symptoms and prognosis. Fifty children (mean age 10.9 months, range: 1–34 months) with previously confirmed CMA were enrolled in this study. All had various clinical manifestations of CMA, including gastrointestinal, skin, and respiratory symptoms. At the diagnosis of CMA the serum total and the milk‐specific immunoglobulin (Ig)E values were measured by enzyme immunoassay and fluoroimmunoassay, respectively, while the relative levels of serum IgA and IgG antibodies against different cow's milk proteins were determined by a sensitive enzyme‐linked immunosorbent assay (ELISA). The results were compared to those of 30 non‐atopic age‐matched control children. On average, after 9.2 months (range 2–31 months) on a milk‐free diet, a repeated challenge was performed in 38 children. At the re‐challenge, 12 patients had clinical symptoms while the remaining 26 children were symptom‐free. The IgG antibody level to bovine serum albumin (BSA) was significantly lower in the patients than in the controls (median: 0.36 vs. 2.94, p