Clinical Forms of Human Schistosoma mansoni Infection Are Associated with Differential Activation of T-Cell Subsets and Costimulatory Molecules

The current study has compared the activationstatus and the expression of the CD28 molecule oncirculating CD4⁺ and CD8⁺lymphocytes from patients with different clinical formsof schistosomiasis. The data show that patients with acuteschistosomiasis have an increase on the mean percentageof CD4⁺HLA-DR⁺ cells, whereaschronic asymptomatic patients exhibit an increased meanpercentage of CD8⁺HLA-DR⁺ cells. Patients with the hepatosplenic diseaseshowed an increase in bothCD4⁺HLA-DR⁺ andCD8⁺HLA-DR⁺ cells. Despite thehigh levels of CD8⁺HLA-DR⁺ cellsin hepatosplenic patients, they presented a decreased ratio ofCD8⁺CD28⁺/CD8⁺ cells.These findings of a different percentage of circulatingCD8⁺CD28⁺ cells might explain thedifferent in vitro cellular reactivity of asymptomaticand hepatosplenic patients and the defects in the cytokine secretionpatterns reported in individuals with hepatosplenicschistosomiasis.