1Departments of Immunology and ²Surgery, Medical Research Institute, Alexanderia University, ³Central Research laboratories, NAMRU-3, Cairo, Egypt.

Previously, we have demonstrated a differential cellular immune responsiveness in hepatosplenic schistosomiasis mansoni infection [HS]. To find out if such phenomenon is also demonstrable in the humoral immune responsiveness; splenocytes from 23 patients with hepatosplenic schistosomiasis mansoni were analyzed phenotypically as well as functionally for their in vitro antibody production in response to pokeweed mitogen [PWM], soluble egg antigen [SEA] and adult worm antigen [AFT] using the protein A plaque assay. Normal spleen cells obtained during upper gastrectomy were used for comparison purposes. Phenotypic analysis showed a low frequency of splenic CD4⁺ cells in HS patients compared to the reference group and resulted in a marked decrease in the Th:Ts cell ratio. In a hemolytic plaque assay, HS splenocytes were incapable of in vitro producing IgM antibody in response to mitogenic and antigenic stimuli. The differential cellular responsiveness observed in HS group was not reflected on the humoral immune responsiveness. The functional defect might have resulted from inadequate response by CD4⁺ cells reflecting its low number or from it’s cytokine dysregulation. In fact, IL4 production in response to PWM was higher in the hepatosplenic group compared to the control group. Collectively the result favor the notion that increased periportal fibrosis is correlate to an imbalance of T helper 2 cytokine response.