Schistosoma mansoni infection alters co-stimulatory molecule expression and cell activation in asthma

Abstract

Chronic schistosomiasis induces Th2/T regulatory responses which are able to down-modulate allergic inflammation and asthma. Because costimulatory molecules and IL-10 are essential for inducing tolerance, the aim of this study was to determine by flow cytometry, the expression of CD28, CTLA4, CD40L, CD80, CD86, HLA-DR, IL-10 and IL-10 receptor, by mononuclear cells from asthmatic individuals infected with Schistosoma mansoni and compare with non-infected individuals. Peripheral blood mononuclear cells were stained with fluorochrome conjugated antibodies for the expression of co-stimulatory molecules, and for intracellular CTLA4 and IL-10 expression. There was no significant difference in the frequency of T cells expressing CD28 between the two groups. However, the frequency of TCD4þ cells expressing CTLA4 and CD40L was higher in infected asthmatics. The frequency of monocytes expressing CD80 and CD86 did not differ between groups, while the expression of HLA-DR and IL-10 receptor was higher on monocytes of infected individuals. Furthermore, monocytes and CD4þCD25þ cells of infected individuals expressed higher levels of IL-10. We conclude that, besides alternatively-activated monocytes that are, together with CD4þCD25þ cells, important sources of IL-10, CTLA4 and CD40L expression may also participate in the down-modulation of inflammatory allergic response in S. mansoni-infected asthmatics. 2008 Published by Elsevier Masson SAS.