Ascariasis as a model to study the helminth/allergy relationships

Ascaris lumbricoides causes ascariasis. There are many similarities in the host’s immune response during parasitic infestation and allergic diseases. Four A. lumbricoides proteins from the official list of WHO/IUIS allergens, i.e. Asc s 1 (polyprotein, ABA-1), Asc l 5 (SXP/RAL-2), Asc l 3 (tropomyosin) and Asc l 13 ( glutathione transferase, GSTA) have been decribed. A meta-analysis of several epidemiological studies has shown that active A. lumbricoides infestation and the related IgE-mediated host response is a risk factor for the development of asthma and atopy, and this relationship is stronger in patients additionally allergic to house dust mites. Moreover, recent studies have indicated that parasitic infestation induces the synthesis of IgE antibodies against a wide range of N-glycans. The presence of the carbohydrate epitope galactose-α-1,3-galactose (α-gal) in A. lumbricoides glycoproteins was found at a higher concentration than in Amblyomma hebraeum and Rhipicephalus evertsi ticks. The equivalence of symptoms of parasitosis and allergy indicates the need for parallel differential diagnosis of both diseases and the legitimacy of using ascariasis as a model to study the parasite/allergy relationship.