These IgE antibodies were shown to be specific for an oligosaccharide, galactose-α-1,3-galactose, which is present on the Fab portion of the cetuximab heavy chain.29 The presence of such IgE antibodies before treatment may put patients who receive monoclonal antibodies containing galactose-α-1,3-galactose at risk for hypersensitivity reactions.29 A blood test for IgE specific for the oligosaccharide on cetuximab would be the easiest and most reliable screening test to prevent these hypersensitivity reactions.30 Here, IGHE is linked to hypersensitivity.