Figure 3. T lymphocyte and NK cell profile in blood of patients.

(A -C) Activated effector CD8 T cells, CD4:CD8 T lymphocyte ratio and NK cell frequencies in the three patients (H1N1/09 ITU) compared to the other groups as described in Methods. (D) CD8 T lymphocytes specific to H1N1 matrix epitope as detected by MHC1 tetramer loaded with Matrix peptide. P1 – Patient 1; P2 – Patient 2; C1 – non-HLA A*0201 individual as control (should not stain); H2 and H5 – two healthy individuals with HLA A*0201 genotype; P4 – infected, non-ventilated patient with HLA A*0201 genotype. H5 had symptoms suggestive of influenza virus A infection a few years ago. (E). NK cells identified by CD56⁺ and CD3^- staining. NK cells were all CD16⁺ for P2 and 3. P1-3 – Patient 1-3; Pr1-3 – healthy uninfected pregnant women; H1-6 – healthy uninfected individuals. In (D), % refers to frequencies of tetramer⁺ cells as proportion of CD3 T cells. And in (E), both CD56^bright and CD56^dim subsets as proportion of live PBMCs.