Some miRNAs also impact effector CD8 T cell proliferation and memory cell differentiation, as shown for the miR-17-92 cluster in the context of viral infection [24], whereas others bias CD8 T cell responses away from memory and toward effector CD8 T cell functions, as it is the case of miR-21, whose levels are associated with increased numbers of inflammatory effector T cells [25]. This evidence concerns the gene CD8A and viral infectious disease.