title: Elevated numbers of Fc gamma RIIIA+ (CD16+) effector CD8 T cells with NK cell-like function in chronic hepatitis C virus infection.
abstract: CTL are crucial in the defense against viral infections. In the course of investigating peripheral blood and intrahepatic CD8 T cells in patients with chronic hepatitis C virus (HCV) infection, we observed a significant population of CD8 T cells expressing the FcgammaRIIIA (CD16) receptor. This observation led us to characterize these cells with respect to their phenotype and function in a cohort of patients with chronic HCV infection as well as in healthy blood donors. On average, 10% of peripheral blood CD8 T cells from HCV-infected patients expressed CD16 compared with only a few percent in healthy donors. CD16(+) CD8 T cells displayed a late-stage effector phenotype with high levels of perforin. These cells exhibited a restricted TCR profile suggesting underlying clonal expansion. Stimulation of CD16 on CD8 T cells evoked a vigorous response similar to that of CD16 stimulation in NK cells. Our data suggest that CD8 T cells, during chronic HCV infection in humans, continue to differentiate beyond defined stages of terminal effector cells, acquiring CD16 and NK cell-like functional properties.
authors.affiliation: Center for Infectious Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden. Niklas.bjorkstrom@ki.se
authors.forename: Niklas K
authors.initials: NK
authors.lastname: Björkström
authors.forename: Veronica D
authors.initials: VD
authors.lastname: Gonzalez
authors.forename: Karl-Johan
authors.initials: KJ
authors.lastname: Malmberg
authors.forename: Karolin
authors.initials: K
authors.lastname: Falconer
authors.forename: Annette
authors.initials: A
authors.lastname: Alaeus
authors.forename: Greg
authors.initials: G
authors.lastname: Nowak
authors.forename: Carl
authors.initials: C
authors.lastname: Jorns
authors.forename: Bo-Göran
authors.initials: BG
authors.lastname: Ericzon
authors.forename: Ola
authors.initials: O
authors.lastname: Weiland
authors.forename: Johan K
authors.initials: JK
authors.lastname: Sandberg
authors.forename: Hans-Gustaf
authors.initials: HG
authors.lastname: Ljunggren