Is there a link between environmental allergens and parasitism

Abstract Helminth infections and allergic diseases elicit strong Th2 responses. The up-regulation of IL-4, IL-13, IL-5, IL-9, total IgE, eosinophils and macrophages are part of the host immune response against helminths and also compose an immunological pattern that accompanies allergic diseases. These facts together with the common features observed between allergens and parasite antigens suggest that the immune response to helminths and allergy could have developed under the same evolutionary process. However, asthma can have a positive or negative association with helminth infections, depending on several factors, such as the helminth species, the clinical status of infection, host genetics, or intensity of infection. The model of immune regulation observed in helminths can be very useful for developing alternative strategies for the prevention, treatment, and control of inflammatory diseases including allergic diseases. Helminth infections induce a complex immune regulatory network that utilizes dendritic cells, Treg cells and systematic elevated levels of IL-10 and possibly TGF-β, B reg cells and activated macrophages to achieve chronic asymptomatic conditions that can be used as a model to design the aforementioned strategies.