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.