IFNG and influenza: Finally, an analysis of the double positive cell population, expressing both IFN-γ and granzyme B, showed significantly higher cell numbers (SFU/million) on day 42 than on day 0 for H1N1 (medians: 25 vs. 125, p < 0.0011), H3N2 (medians: 135 vs. 220, p = 0.0064), H5N1 (medians: 245 vs. 305, p = 0.0220), and B influenza (medians: 10 vs. 30.