Activities of IL-1 produced by peripheral blood monocytes stimulated with lipopolysaccharide and IL-2 released by peripheral blood mononuclear cells induced by PHA, SWAP and SEA in vitro were detected in patients with various stages of schistosomiasis japonica. It was found that the activity of IL-1 was greatly increased and positively related to the body temperature, and high level of IL-2 was induced by SWAP and SEA in the group of acute schistosomiasis. The activity of IL-1 was significantly reduced in the groups of chronic and advanced schistosomiasis, especially in the latter group. The level of IL-2 induced by SWAP and SEA in the groups of chronic and advanced schistosomiasis was significantly lower than that in the group of acute schistosomiasis, but was much higher than that in the group of normal control. The level of IL-2 induced by SWAP and SEA in the cases of acute schistosomiasis was positively related to the activity of IL-1. The results indicate that the specific cellular immunity was increased in acute cases and decreased in chronic cases of schistosomiasis japonica. Both specific and nonspecific cellular immune responses were greatly reduced in cases of advanced schistosomiasis japonica. IL-1 and IL-2 may play an important role in the immunoregulation of schistosomiasis japonica.