Chang points out that IgE's specific immunological function has never been confirmed. Some think IgE is related to defense against human parasites, but currently in more developed countries--the ones where allergies are more common--parasites are not a major health concern.
張子文指出，IgE 的特定免疫功能其實一直無法被確認，有人認為 IgE 與人體寄生蟲的防禦有關，但目前在先進國家──即過敏較普遍國家中，寄生蟲已不是首要的衛生議題。