Chapter 2 - Ascaris and Allergy

Abstract

Ascaris lumbricoides infects humans causing ascariasis. The immune response to this helminth shares mechanisms with the allergic reaction and may influence the natural history of allergy phenotypes. The high levels of total IgE associated with ascariasis restrict the use of this test in the diagnosis of allergy. Also, the immunological cross-reactivity between Ascaris and domestic mites has implications in the diagnosis of both allergy and ascariasis. Depending on the infection intensity and host’s susceptibility, in countries where helminthiases are still present ascariasis may confer risk or protection for allergy, modifying its prevalence and severity. In parasite-free countries, the lack of helminth-induced immunomodulation could have contributed to the increase in allergic diseases. Other interesting aspects are the role of helminth infections in the evolution of allergic inflammation and the potential usefulness of Ascaris immunomodulator molecules in the treatment of allergic diseases.