HLA-E and influenza: The combined observation of induced expression of NKG2A on antigen specific CD8+ T cells in influenza infection, dampened cytokine production upon ligation of NKG2A on CD8+ T cells, and the dramatic immunopathology evident in Qa1-deficient mice upon CD8+ T cell clearance of influenza infection strongly pointed to a key role of CD8+ T cell NKG2A expression in abrogating tissue destruction during virus clearance [28].