IGHE and plasma cell myeloma: In the case of mouse myeloma-derived monoclonal antibody Erbitux (cetuximab, Merck), in certain populations, the preexistence of IgE antibodies against the galactose-α(1-3)-galactose epitope present on the carbohydrate of Erbitux caused severe hypersensitivity reactions and anaphylactic shocks in patients [78].