Reduced helminth burden increases allergen skin sensitization but not clinical allergy: a randomized, double‐blind, placebo‐controlled trial in Vietnam

Abstract

A significant reduction in worm burden over a 12-month period in helminth-infected children increases the risk of allergen skin sensitization but not of clinical allergic disease. The effect on skin sensitization could not be fully explained by any of the immunological parameters tested.

Community deworming alleviates geohelminth-induced immune hyporesponsiveness

“…Longitudinal studies assessing the effect of anthelmintic treatment on cellular immune responsiveness are rare and either lack placebo controls, target children only, or measure immune responses at one time point posttreatment (14)(15)(16). Moreover, none have examined the changes in regulatory cells or molecules.…”

Suppression of type 2 immunity and allergic airway inflammation by secreted products of the helminth Heligmosomoides polygyrus

“…While a causal link between human helminth infections and reduced allergy has yet to be proven [2], chemotherapeutic clearance of intestinal helminths can result in accentuated atopic responsiveness [11][12][13] and helminth infection blocks overt allergy in a number of animal models [14][15][16][17]. The degree to which helminths may influence allergy, however, is clearly variable between different parasite species [18], and is probably dependent upon the duration and intensity of infection [2,19], each factors that need to be taken into account in assessing this interaction.…”

“…This contrasts with much lower asthma incidence in tropical countries that have significant levels of parasite infections, and these observations have stimulated research into the effects of parasitic organisms on human allergy [2][3][4]. From these studies, it has emerged that allergic diseases are least common in parts of the world with high helminth endemicity, and that within endemic populations the prevalence of atopy is significantly lower in individuals with chronic worm infections [5][6][7][8][9][10].Correspondence: Dr. Rick M. Maizels e-mail: rick.maizels@ed.ac.ukWhile a causal link between human helminth infections and reduced allergy has yet to be proven [2], chemotherapeutic clearance of intestinal helminths can result in accentuated atopic responsiveness [11][12][13] and helminth infection blocks overt allergy in a number of animal models [14][15][16][17]. The degree to which helminths may influence allergy, however, is clearly variable between different parasite species [18], and is probably dependent upon the duration and intensity of infection [2,19], each factors that need to be taken into account in assessing this interaction.…”

Pathogenic Nematodes Suppress Humoral Responses to Third-Party Antigens In Vivo by IL-10–Mediated Interference with Th Cell Function

“…Regarding situations of coinfection, helminth-induced immune modulation may interfere with the control of coinfecting parasites but may also help to avoid immune pathology such as development of cerebral malaria (11,12). Finally, the attenuation of autoimmune diseases has been attributed to preexisting helminth infections (13)(14)(15).…”