Modulation of the immune response by infection with Cryptosporidium spp. in children with allergic diseases.

It has been demonstrated that the allergic response can be ameliorated by the administration of pathogen derivatives that activate Toll-like receptors and induce a Th1-type immune response (IR). Cryptosporidium is a parasite that promotes an IR via Toll-like receptors and elicits the production of Th1-type cytokines, which limit cryptosporidiosis. The aim of this study was to investigate allergy-related immune markers in children naturally infected with Cryptosporidium. In a cross-sectional study, 49 children with or without clinical diagnosis of allergies, oocysts of Cryptosporidium spp. in the faeces were screened microscopically. We microscopically screened for leucocytes, examined T and B cells for allergy-related activation markers using flow cytometry and evaluated serum for total IgE using chemiluminescence. Children with allergies and Cryptosporidium in the faeces had significantly lower levels of total IgE, B cells, CD19(+) CD23(+) and CD19(+) CD124(+) cells as well as a greater percentage of interferon-gamma (IFN-γ(+) ) and IL-4(+) CD4(+) cells than children with allergies without Cryptosporidium. This is the first description of the modulation of the IR in children with allergic diseases in the setting of natural Cryptosporidium infection. Our findings suggest the involvement of CD4(+) cells producing IL-4 and IFN-γ in the IR to Cryptosporidium in naturally infected children.