Immune Response in Asthma: Down Modulation by Schistosoma Mansoni Infection

RATIONALE: Allergic diseases are highly prevalent in many areas of the world and lead to production of IL-4, IL-5 and IL-13, which are involved in the pathogenesis of these diseases. IL-10, capable of inhibiting the release of histamine and other mediators by mast cells, is highly produced by PBMC of individuals infected with Schistosoma mansoni, and possibly inhibits the reactivity of skin tests observed in schistosomiasis. In this study we evaluated the D. pteronyssinus-induced immune response of asthmatic individuals infected or not with S. mansoni. The role of IL-10 in modulating the immune response through the addition of the mAb anti-IL-10 or rhIL-10 to PBMC culture stimulated with Der p 1 was also evaluated. METHODS: Thirty-three patients living in a polyhelminthic endemic area, Conde, Brazil were selected for the study and ten asthmatic individuals free of parasites, living in a non-endemic area were used as controls. RESULTS: Asthmatic patients from the polyhelminthic endemic area produced low levels of IL-5 in cultures stimulated with Der p1 antigen, while those from the non-endemic area produced high levels of this cytokine. In contrast, Der p Ag-driven IL-10 production was higher in patients from the endemic area than in the control group. Addition of rhIL-10 to the culture of the controls stimulated with Der p lead to a down regulation of IL-5 production. CONCLUSION: It was demonstrated that IL-10 is produced predominantly by monocytes and CD8+T cell. Production of regulatory cytokine, such as IL-10, could represent important mechanisms of down regulation of the inflammatory response in allergies.