Background: The prevalence of asthma and atopic disease has been reported to be low in low income countries, however helminth infections are likely to be high among these communities. The question... Show moreBackground: The prevalence of asthma and atopic disease has been reported to be low in low income countries, however helminth infections are likely to be high among these communities. The question of whether helminth infections play a role in allergic diseases can best be addressed by intervention studies. None of the studies so far have been based on a large scale placebo-controlled trial. Method/Design: This study was designed to assess how intestinal helminth infections can influence the immune response and atopic and allergic disorders in children in Indonesia. The relations between allergic outcomes and infection and lifestyle factors will be addressed. This study was set up among school-age children in semi urban and rural areas, located in Ende District of Flores Island, Indonesia. A randomized placebo-controlled anthelmintic treatment trial to elucidate the impact of helminth infections on the prevalence of skin prick test (SPT) reactivity and symptoms of allergic diseases will be performed. The children living in these semi-urban and rural areas will be assessed for SPT to allergens before and after 1 and 2 years of treatment as the primary outcome of the study; the secondary outcome is symptoms (asthma and atopic dermatitis); while the tertiary outcome is immune responses (both antibody levels to allergens and cellular immune responses). Discussion: The study will provide information on the influence of helminth infections and anthelmintic treatment on immune response, atopy and allergic disorders. Show less
Parasitic infections are common in many tropical and sub-tropical regions of the world and concomitant infection, polyparasitism, is the rule rather than the exception in such areas. At the... Show moreParasitic infections are common in many tropical and sub-tropical regions of the world and concomitant infection, polyparasitism, is the rule rather than the exception in such areas. At the immunological level, different parasites induce quite different responses characterised, for example, by protozoa that polarise responses towards Th1, whilst helminths are strong Th2 and regulatory T cell inducers. The question of how the co-existence of such parasites within the same host might influence the immunological responses to each species and, more importantly, whether such interactions affect resistance, susceptibility or clinical outcome, needs to be addressed in well-designed studies of sufficient power. The current paper discusses what we know as well as the gaps in our knowledge of polyparasitism. (C) 2010 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved. Show less
Background: Given that helminth infections are thought to have strong immunomodulatory activity, the question whether helminth infections might affect responses to malaria antigens needs to be... Show moreBackground: Given that helminth infections are thought to have strong immunomodulatory activity, the question whether helminth infections might affect responses to malaria antigens needs to be addressed. Different cross-sectional studies using diverse methodologies have reported that helminth infections might either exacerbate or reduce the severity of malaria attacks. The same discrepancies have been reported for parasitemia. Methods/Design: To determine the effect of geohelminth infections and their treatment on malaria infection and disease outcome, as well as on immunological parameters, the area of Nangapanda on Flores Island, Indonesia, where malaria and helminth parasites are co-endemic was selected for a longitudinal study. Here a Double-blind randomized trial will be performed, incorporating repeated treatment with albendazole (400 mg) or placebo at three monthly intervals. Household characteristic data, anthropometry, the presence of intestinal helminth and Plasmodium spp infections, and the incidence of malaria episodes are recorded. In vitro cultures of whole blood, stimulated with a number of antigens, mitogens and toll like receptor ligands provide relevant immunological parameters at baseline and following 1 and 2 years of treatment rounds. The primary outcome of the study is the prevalence of Plasmodium falciparum and P. vivax infection. The secondary outcome will be incidence and severity of malaria episodes detected via both passive and active follow-up. The tertiary outcome is the inflammatory cytokine profile in response to parasite antigens. The project also facilitates the transfer of state of the art methodologies and technologies, molecular diagnosis of parasitic diseases, immunology and epidemiology from Europe to Indonesia. Discussion: The study will provide data on the effect of helminth infections on malaria. It will also give information on anthelminthic treatment efficacy and effectiveness and could help develop evidence-based policymaking. Show less
Wammes, L.J.; Hamid, F.; Wiria, A.E.; Gier, B. de; Sartono, E.; Maizels, R.M.; ... ; Yazdanbakhsh, M. 2010
Chronic helminth infections induce T-cell hyporesponsiveness, which may affect immune responses to other pathogens or to vaccines. This study investigates the influence of Treg activity on... Show moreChronic helminth infections induce T-cell hyporesponsiveness, which may affect immune responses to other pathogens or to vaccines. This study investigates the influence of Treg activity on proliferation and cytokine responses to BCG and Plasmodium falciparum-parasitized RBC in Indonesian schoolchildren. Geohelminth-infected children's in vitro T-cell proliferation to either BCG or pRBC was reduced compared to that of uninfected children. Although the frequency of CD4(+)CD25(hi)FOXP(3+) T cells was similar regardless of infection status, the suppressive activity differed between geohelminth-infected and geohelminth-uninfected groups: Ag-specific proliferative responses increased upon CD4(+)CD25(hi) T-cell depletion in geohelminth-infected subjects only. in addition, IFN-gamma production in response to both BCG and parasitized RBC was increased after removal of CD4(+)CD25(hi) T cells. These data demonstrate that geohelminth-associated Treg influence immune responses to bystander Ag of mycobacteria and plasmodia. Geohelminth-induced immune modulation may have important consequences for co-endemic infections and vaccine trials. Show less
