By contrast, RAG−/− mice that had received IL-10−/− CD4+ T cells were somewhat better able to control infections with 103 (8E–H) or 104 (8I–L) PyL infections than were mice receiving WT CD4+ T cells; a proportion of mice receiving IL-10−/− T cells were able to control their infections, although failure to fully eliminate parasites eventually led to death from anaemia. This evidence concerns the gene CD4 and anemia (phenotype).