Helminth infections are highly prevalent worldwide, with more than two billion people chronically infected by soil transmitted helminths such as Ascaris lumbricoides, Trichuris trichiura and/or hookworms (Necator americanus or Ancylostoma duodenale) . These enteric infections affect populations living in subtropical and tropical regions of low-middle income countries, where access to hygiene, sanitation and source of clear water is limited . The immune responses mounted to helminth infections is characterized by T-helper type 2 (Th2), which are thought to be protective . However, there is also evidence that these parasites might enhance their own survival by modulating the immune responses of their host by inducing regulatory responses that dampen activity of effector cells . Whether all different helminths are equally potent in inducing regulatory responses is as yet not fully studied.
Allergens, like helminth antigens [5, 6] are potent inducers of Th2 responses  and it is known that allergic diseases including asthma, eczema and rhinitis are associated with Th2 inflammation . However, in contrast to helminth infections the Th2 associated allergic diseases, which are the most common cause of chronic disease of childhood in high income countries, appear to be less common in low income countries . Thus, despite the close parallels between immune responses that characterize helminth infections and allergic diseases, namely increased levels of Immunoglobulin (Ig)-E, tissue eosinophilia and mastocytosis along with T cells that preferentially secrete Th2 cytokines interleukin (IL)-4, IL-5 and IL-13 [8, 10–12], the clinical outcome with respect to immediate hypersensitivity and inflammation is clearly not the same . Indeed, often it has been reported that these diseases, appear to segregate geographically  and several studies have reported a negative association between the presence of helminth infections and allergic disorders [15–18]. In experimental animal models, several parasitic helminths have been shown to prevent the development of eosinophilic airway inflammation and hyperresponsiveness [19–21].
Mechanistically, a number of immune responses have been proposed to account for the negative association between helminths and allergies . The observations that chronic helminth infections are associated with higher suppressive responses, such as IL-10  and regulatory T cells [24, 25] have led to the proposal that a strong regulatory network induced by helminths might prevent the downstream effector phase of Th2 responses, preventing excess inflammation. Moreover, the possibility that in the presence of helminth infections, IgE antibodies generated are of lower affinity and therefore can not lead to mast cell degranulation has also been put forward .
Given that a number of studies have on the other hand reported either no [26, 27] or a positive [28, 29] association between helminths and allergies, it is very likely that apart from the source and chronicity of infection other factors such as exposure to non-helminth infections, and/or lifestyle play an important role in the development of allergies. The change from traditional to a more "modern" lifestyle which encompasses not only reduced exposure to micro-organisms and parasites but also an altered diet, in addition to changes in degree of manual labour or inhalation of pollutants is clearly associated with changing disease patterns . It is important to study and delineate the mechanisms that may protect from the development of allergic diseases. It is becoming clear that the prevalence of allergic diseases is increasing in low to middle income countries  particularly in urban centers which often show higher prevalence of these diseases compared to rural areas [14, 31, 32]. It is therefore important to use this window of opportunity to identify risk and protective factors in cross sectional as well as longitudinal studies.
A study that would include both helminth infections and life style factors with respect to the development of allergies has been planned in Indonesia. The question of whether helminth infections play a role in allergic diseases can best be addressed by intervention studies. So far, one intervention study has suggested that anthelmintic treatment might increase the incidence of atopy reactivity , which is in contrast to a large scale study where one year after treatment of intestinal helminths no changes were recorded in allergic disorders . None of the studies have been based on a large scale placebo controlled trial. Although there clearly are ethical issues with such a design, the ethics committee of University of Indonesia, has granted permission for a placebo controlled trial providing that the community gets extensive medical care and excludes those with intense infections. In addition to helminth infections, the study of how other factors may contribute to the development of allergies is best achieved by longitudinal comparison of different areas along a rural-urban gradient. Numerous studies have analyzed the difference in the prevalence of allergic disorders in a rural to urban gradient  but none so far has done so in a longitudinal manner with the exception of one study in Ghana .
The ImmunoSPIN allergy project http://www.immunospin.org has been initiated with this aim. This study is a randomized placebo-controlled anthelmintic treatment trial to elucidate the impact of helminth infections on the prevalence of atopy and allergic diseases. In this study the prevalence of IgE, skin prick test positivity and symptoms of allergic diseases such as asthma and atopic dermatitis in school-age children will be assessed in semi-urban and rural area in Flores, Indonesia. The ImmunoSPIN allergy project will establish the risk and protective factors and will include immune response measurements in order to understand the immunological mechanisms that are behind risk and protective factors in allergy development.