1Microbiology Department. Faculty of Medicine for Girls, AL-Azhar University, ²National Center for Radiation Research and Technology, Cairo and ³Tropical Medicine research Institute, Cairo Egypt.

We have previously demonstrated that the in vitro granuloma (IVG) assay reflects T-cell reactivity and correlates with resistance to reinfection with Schistosoma mansoni. The aim of the present study is to examine the role of IL-4 in the formation of IVG reaction and modulation of the disease in human. The study includes twenty one patients with active schistosomiasis and ten former subjects as controls. The first group were further categorized according to sonographic and parasitological examination into hepatosplenic (n=10) and intestinal (n=11). The mean ages (year) were 13.66 ± 0.69, 13.3 ± 0.85 and 14.18 ± 96 in hepatosplenic, intestinal and former groups respectively. In vitro granuloma assay was carried out using polyacrylamide beads coated with soluble egg antigen (SEA). The presence of IL-4 in the 24h-IVG supernatants was determined using ELISA. The IL-4 level (mean ± SEM) was significantly elevated in the hepatosplenic (5.32 ± 1.03 ng/ml) as compared to the intestinal (2.58 ± 0.37 ng/ml) and to the formerly treated (2.45 ± 0.21 ng/ml) control groups (P £ 0.001 ). It is concluded that IL-4 is the key cytokine in the IVG reaction and that its level in the 24h-IVG supernatant reflects the in vivo pathological stage of the disease.