Figure 1. Frequency of NK cells and the immature/regulatory CD56^bright subset in acute HCV infection.

A) Multi-parameter flow cytometric analysis was used to determine if the levels of peripheral NK cells (CD56⁺CD3^-) were altered in acute HCV infection. B) Levels of total NK cells at time of enrollment and at six and twelve month follow up time points are similar to those detected in normal uninfected controls irrespective of subsequent clinical outcome. C) In contrast, an increase in the proportion of NK cells displaying a CD56^bright immature/regulatory phenotype was observed at baseline in acute HCV infection per se with a trend that was more pronounced in chronically evolving infection compared to patients who subsequently resolved infection. The relatively high proportion of NK cells with an immature/regulatory phenotype was maintained in the chronically evolving cohort and returned to normal levels in the spontaneously resolving patient group at six and twelve months post enrollment. * p<0.05 chronic versus resolved; † p<0.05 versus uninfected control (MWU).