Changes in NK cell numbers and subset distribution in acute influenza infection and influenza vaccination.

<p>Dot plots represent (A), absolute numbers of NK cells (B), percentages of total NK cells and (C), absolute numbers of CD56^bright (CD3-CD56+CD16−), CD56^dim (CD3-CD56+CD16+) and CD56^neg (CD3-CD56−CD16+) NK cells from 17 subjects prior to influenza vaccination, and at day 1 and 4 post-vaccination, 9 patients with acute seasonal influenza and 21 with acute 2009 pandemic H1N1 influenza virus infection. Complete blood counts at baseline were only available for 13 of the vaccinated subjects. Horizontal lines indicate the median percentages. Differences where p<0.05 are indicated. (•, healthy subjects prior vaccination; ▪, healthy subjects post-vaccination; dark grey ▴, acutely infected with 2009 seasonal influenza strains; light grey ▴, acutely infected with 2009 pandemic H1N1 influenza virus). D: day post-vaccination.