Abstract
Summary
A new glass microfibre histamine release method was used to study the modulation of the host response in human schistosomiasis mansoni to improve our understanding of the role of basophils in the development of immunity in schistosomiasis mansoni. The histamine release from umbilical cord blood basophils sensitized with sera from Sudanese individuals infected with Schistosoma mansoni was measured. Schistosomiasis sera (n=113) were able to passively sensitize basophils and induce a positive histamine release in response to whole worm homogenate (WWH)(χ=40.5, P<0.0001) and soluble egg antigen (SEA) (χ=16.3, P<0.0001). However, worm antigen induced significantly higher histamine release in adults than egg antigen (Z= 4.83, P<0.0001). Basophil cell sensitivity to WWH was inversely related to the intensity of infection. A correlation was observed between basophil cell sensitivity and IgE antibodies in response to WWH. Chronically infected canal cleaners (n=16) showed a significant increase in basophil cell sensitivity 3 months after praziquantel treatment (Z= 1–73, P<0.05). Normally exposed adults (n= 29) showed a significant decrease in basophil cell sensitivity 1 year after treatment. When serum fractions were used, chronically infected canal cleaners showed a significant increase in histamine release after IgG removal (P<0.05)
Comparison between the different study groups with regard to resistance and susceptibility to reinfection, their basophil sensitizing ability and antibody response showed a difference in the biological function of the IgE to WWH in the different groups. Direct histamine release results from S. mansoni infected individuals from outside the endemic area (Danish) showed the possibility of using the glass microfibre histamine release method in the diagnosis of schistosomiasis.