Schistosome-induced pathology is exacerbated and Th2 polarization is enhanced during pregnancy.

UNLABELLED: THE AIM of this study was to investigate the immunopathological impact of pregnancy on an ongoing experimental schistosomiasis infection.

MATERIALS AND

METHODS

Female BALB/c mice were randomly divided into three groups (A, B and C) of 15 animals each. The mice in Groups A and B were infected with 40 S. mansoni cercariae, percutaneously. Six weeks post-infection, the mice in Groups B and C (schistosome-naive controls) were mated. Schistosome-induced morbidity and cytokine recall responses were subsequently evaluated at weeks 7 and 8 post-infection.

RESULTS

Hepatic and pulmonary lesions resulting from trapped schistosome eggs were more frequent and more severe in Group B mice than in Group A mice. Group C mice had suppressed mitogen-stimulated interleukin 4 (IL-4) but maintained high intereferon gamma (IFN-gamma) responses. In contrast, Group A mice had elevated mitogen- and parasite-specific IL-4 but muted IFN-gamma responses. Group B mice had an early (week 7) high IL-4 response, even higher than in group A mice.

CONCLUSION

Taken together the data suggest that pregnancy exacerbates schistosome-induced morbidity, probably through up-regulation of parasite-specific IL-4.