Asthma, a chronic inflammatory disorder of the airways, is coordinated by Th2 
cells in both human asthmatics and animal models of allergic asthma. It has been 
shown that helminth infections including Schistosoma mansoni may modulate atopic 
diseases including asthma. In the present study, BALB/c mice were infected with 
bisexual and unisexual (male) S. japonicum, respectively, prior to ovalbumin 
(OVA) sensitization and challenge. Compared to mice with OVA 
sensitization/challenge alone, S. japonicum infection led to a significant 
decrease of eosinophil accumulation in bronchoalveolar lavage fluid (BALF) 
collected 48 h postchallenge, as well as to a marked reduction in inflammatory 
cell infiltration around the airways and pulmonary blood vessels. Compared to 
OVA-immunized uninfected mice, the level of OVA-specific serum IgE as well as 
interleukin (IL)-4 and IL-5 in BALF were reduced, but IL-10 was strongly 
elevated in mice with preexisting S. japonicum infection prior to OVA 
immunization. These results suggest that both bisexual and male S. japonicum 
infections may modulate the development of allergic asthma.