Risk for influenza increases with age while cellular immune responses decli
ne. This was a prospective study to determine the relationship between cyto
kine and granzyme B levels in peripheral blood mononuclear cells stimulated
with live influenza virus, and subsequent influenza illness. Granzyme B le
vels were lower in the group who later developed symptomatic laboratory-con
firmed influenza (n = 10) compared to the group who did not (n = 90) (ANOVA
, P = 0.024). In contrast, none of the cytokine levels were related to the
development of influenza. Thus, granzyme B is a potential marker of influen
za risk in older adults. (C) 2001 Elsevier Science Ltd. All rights reserved
.