Altered phenotype and functionality of varicella zoster virus-specific cellular immunity in individuals with active infection.

BACKGROUND: Varicella zoster virus (VZV) establishes lifelong persistence and may reactivate in individuals with impaired immune function. To investigate immunologic correlates of protection and VZV reactivation, we characterized specific immunity in 207 nonsymptomatic immunocompetent and 132 immunocompromised individuals in comparison with patients with acute herpes zoster.
METHODS: VZV-specific CD4 T cells were quantified flow cytometrically after stimulation and characterized for expression of interferon-γ, interleukin 2, and tumor necrosis factor α and surface markers for differentiation (CD127) and anergy (cytotoxic T lymphocyte antigen 4 [CTLA-4] and programmed death [PD]-1). Immunoglobulin G and A levels were quantified using an enzyme-linked immunosorbent assay.
RESULTS: In healthy individuals, VZV-specific antibody and T-cell levels were age dependent, with the highest median VZV-specific CD4 T-cell frequencies of 0.108% (interquartile range, 0.121%) during adolescence. VZV-specific T-cell profiles were multifunctional with predominant expression of all 3 cytokines, CD127 positivity, and low expression of CTLA-4 and PD-1. Nonsymptomatic immunocompromised patients had similar VZV-specific immunologic properties except for lower T-cell frequencies (P<.001) and restricted cytokine expression. In contrast, significantly elevated antibody- and VZV-specific CD4 T-cell levels were found in patients with zoster. Their specific T cells showed a shift in cytokine expression toward interferon γ single positivity, an increase in CTLA-4 and PD-1, and a decrease in CD127 expression (all P<.001). This phenotype normalized after resolution of symptoms.
CONCLUSIONS: VZV-specific CD4-T cells in patients with zoster bear typical features of anergy. This phenotype is reversible and may serve as adjunct tool for monitoring VZV reactivations in high-risk patients.