Ascariasis as a model to study the helminth/allergy relationships

Abstract

Summary Ascariasis is the most frequent soil transmitted helminthiasis and, as well as other helminth infections, is expected to influence the clinical presentation of allergic diseases such as asthma. Indeed, several clinical and experimental works have shown an important impact either increasing or suppressing symptoms, and the same effects have been detected on the underlying immune responses. In this review we analyze the work on this field performed in Colombia, a Latin American tropical country, including aspects such as the molecular genetics of the IgE response to Ascaris; the allergenic activity of Ascaris IgE‐binding molecular components and the immunological and clinical influences of ascariasis on asthma. The analysis allows us to conclude that the impact of ascariasis on the inception and evolution of allergic diseases such as asthma deserves more investigation, but advances have been made during the last years. The concurrent parasite‐induced immunostimulatory and immunosuppressive effects during this helminthiasis do modify the natural history of asthma and some aspects of the practice of allergology in the tropics. Theoretically it can also influence the epidemiological trends of allergic diseases either by its absence or presence in different regions and countries.

Prevalence of allergic sensitization to storage mites in Northern Europe

“…Furthermore, tropomyosin is a somatic antigen of the helminth Ascaris lumbricoides , which has been reported to be a primary cause of sensitization to storage mite ( Blomia spp.) in endemic regions . Although data about Ascaris prevalence in the Nordic countries are limited, the exposure to Ascaris can be quite high in these regions, with 29% in the Bergen ECRHS III cohort .…”

“…in endemic regions. 37 Although data about Ascaris prevalence in the Nordic countries are limited, the exposure to Ascaris can be quite high in these regions, with 29% in the Bergen ECRHS III cohort. 38 In the light of extremely low findings of HDM and HDM mite allergens in bedroom mattress samples, identifying cross-reactive proteins of other causes is relevant for future research into the cause of allergies and sensitization to mites.…”

House Dust Mite Allergy Under Changing Environments

“…Regarding allergic diseases, helminth infections have a dual effect: during severe infections they induce immunosuppression of the Th2 response and diminish allergic symptoms. In contrast, when they are light, with low parasitic load, they increase allergic responses 110. Helminth infections are going progressively controlled in most regions, even in developing countries, where they remain as public health problems.…”

“…The mechanisms include the high level of cross-reactivity between HDM and helminth ( e.g. Ascaris lumbricoides ) allergens9798 and non-specific boosting of HDM-specific IgE by still unknown helminth products 110111112. Deworming studies have shown that monthly anthelmintic treatment of children for 18 months caused an increase in the prevalence of skin test reactivity to HDMs in Venezuela113 and that treatment with praziquantel and mebendazole every 3 months for 30-months was associated with an increase in the incidence of skin reactivity to HDMs in Gabon 114.…”

Parasites and allergy: a case of more means less and less means more?

“…Caraballo and colleagues review a series of studies done in Colombian coastal populations where there is a high prevalence of wheeze and asthma and show how Ascaris lumbricoides infection may contribute to the asthma prevalence and disease severity. They also highlight the natural history of parasite and dust mite‐specific responses from birth demonstrating the importance of Ascaris sensitization in potentiating IgE responses to dust mite allergens.…”