USE OF A NEW GLASS MICROFIBER HISTAMINE-RELEASE METHOD TO STUDY THE MODULATION OF THE HOST RESPONSE IN HUMAN SCHISTOSOMIASIS-MANSONI - INDIVIDUALS WITH DIFFERENT DEGREES OF EXPOSURE TO THE DISEASE SHOW DIFFERING ANTIBODY BIOLOGICAL FUNCTION

A new glass microfibre histamine release method was used to study the modulation of the host response in human schistosomiasis mansoni to im prove our understanding of the role of basophils in the development of immunity in schistosomiasis mansoni. The histamine release from umbil ical cord blood basophils sensitized with sera from Sudanese individua ls infected with Schistosoma mansoni was measured. Schistosomiasis ser a (n=113) were able to passively sensitize basophils and induce a posi tive histamine release in response to whole worm homogenate (WWH)(chi( 2)=40.5, P<0.0001) and soluble egg antigen (SEA) (chi(2)=16.3, P<0.000 1). However, worm antigen induced significantly higher histamine relea se in adults than egg antigen (Z=4.83, P<0.0001). Basophil cell sensit ivity to WWH was inversely related to the intensity of infection. A co rrelation was observed between basophil cell sensitivity and IgE antib odies in response to WWH. Chronically infected canal cleaners (n=16) s howed a significant increase in basophil cell sensitivity 3 months aft er praziquantel treatment (Z=1.73, P<0.05). Normally exposed adults (n =29) showed a significant decrease in basophil cell sensitivity I year after treatment. When serum fractions were used, chronically infected canal cleaners showed a significant increase in histamine release aft er IgG removal (P<0.05). Comparison between the different study groups with regard to resistance and susceptibility to reinfection, their ba sophil sensitizing ability and antibody response showed a difference i n the biological function of the IgE to WWH in the different groups. D irect histamine release results from S. mansoni infected individuals f rom outside the endemic area (Danish) showed the possibility of using the glass microfibre histamine release method in the diagnosis of schi stosomiasis.