CD28 and schistosomiasis: In conclusion, the primary outcome of the treatment group was clearing the helminth infection and reducing the parasitic load; beyond this, the study showed that treatment of soil-transmitted helminthiasis and schistosomiasis had a significant effect on IgE levels and eosinophil counts, CD4/CD8 ratio, proportion of HLA-DR+CD3+, HLA-DR+CD4+ and HLA-DR+CD8+ cells, CD45RA+CD4+ (naive) and CD28+CD8+ cells, CD45RO+CD4+ (memory) cells, and secretion of IL-4 and IL-5.