Praziquantel treatment of schistosomiasis boosts antischistosome
responses, with type 2 helper T cell bias that may contribute to immunologically
mediated killing and to protection against reinfection. Praziquantel treatment
during pregnancy was recommended in 2002, but the immunological effects of the
treatment had not been investigated. METHODS: A cohort of 387 Schistosoma
mansoni-infected women were recruited from a larger trial of deworming during
pregnancy. Women were randomized to receive either praziquantel or placebo during
pregnancy. Six weeks after delivery, all women received praziquantel. Cytokine
responses to S. mansoni worm and egg antigens were measured in whole blood
culture before and 6 weeks after each treatment. RESULTS: Schistosome-specific
cytokine responses were suppressed during pregnancy. Praziquantel treatment
during pregnancy caused significant boosts in interferon-gamma (IFN-gamma),
interleukin (IL)-2, IL-4, IL-5, IL-13, and IL-10 responses to schistosome worm
antigen and in IFN-gamma, IL-5, and IL-13 responses to schistosome egg antigen,
but these boosts were not as substantial as those seen for women treated after
delivery. CONCLUSION: Pregnancy suppresses a potentially beneficial boost in
cytokine responses associated with praziquantel treatment. Further studies are
needed on the long-term effects that treatment of schistosomiasis during
pregnancy have on morbidity and resistance to reinfection among treated women and
their offspring.