Final answer:
High levels of circulating IgE are responsible for hypersensitivity reactions in helminth and cestode infections as they play a pivotal role in allergic responses and anti-parasitic defenses.
Step-by-step explanation:
The high levels of circulating IgE may cause hypersensitivity reactions in helminth and cestode infections. IgE has a specific role in defending against parasitic worm infections, for instance, helminths, and plays a significant part in allergic responses. These responses include symptoms such as vasodilation, edema, rash, hay fever, and asthma, which are characteristic of allergies caused by the degranulation of mast cells and release of histamine upon antigen-antibody interaction.
In the context of parasitic infections, the antigen-antibody reaction of IgE on the surface of mast cells promotes the release of pro-inflammatory mediators. This is thought to assist in flushing out the parasites by increasing local vascular permeability. Additionally, if IgE labels the helminth parasite, eosinophils can bind to the parasite via their Fc receptor and attempt to eradicate the infection.