Antibody response to milk proteins in patients with milk-protein intolerance documented by challenge

To evaluate the role of specific antibody response to milk proteins in patients with milk-protein intolerance, allergen-specific IGE, IgG, and IgG4 to these proteins were measured by ELISA. Bovine casein, gamma globulin (GG), β-lactoglobulin, and lactalbumin were the milk proteins used. Antibody production to these proteins were analyzed in 18 patients who underwent milk-protein challenges (eight positive and 10 negative) and in five normal children used in the analysis. ELISA results for specific IgE, IgG, and IgG4 to these specific proteins demonstrated no statistically different response to the four milk proteins among the three patient groups by multivariate analysis. When the specific antibody results from the positive challenge group, the negative challenge group, and the normal group were combined, the IgE and lgG4 to GG and the IgG to casein were significantly higher ( p < 0.01) than the corresponding specific antibody to the other proteins tested. The IgG or IgG4 to GG would differentiate the positive from the negative challenge group ( p < 0.05) but were not significantly different from the normal control group. Contrary to previously published studies, these results indicate IgG specific for the milk proteins are not increased in patients with milk-protein intolerance. The data also support the concept that IgE and IgG4 are not elevated in these patients. Therefore, there appears to be no pathogenic role for these specific immunoglobulins in milk-protein intolerance.