CTLA-4-expression on VZV-specific T cells in CSF and blood is specifically increased in patients with VZV related central nervous system infections.

VZV-reactivation may lead to symptomatic central nervous system (CNS) diseases, but identification of VZV as causative pathogen of CNS-diseases is challenging. This study was performed to characterize VZV-specific T cells from cerebrospinal fluid (CSF) and blood of patients with active CNS-disease and to determine whether this may improve differential diagnosis. 27 patients with pleocytosis in the CSF were recruited and classified into three groups (10 VZV-related, 10 non-VZV-related, 7 unclear). VZV-specific CD4+ T cells were quantified in CSF and blood after simultaneous stimulation with a VZV-antigen lysate and detection of cytokines (IFN-γ, IL-2, TNF-α) and CTLA-4. Polyclonal stimulation served as positive control. VZV-specific CD4+ T-cell frequencies were highest in both CSF (p = 0.0001) and blood (p = 0.011) of patients with VZV-infection, and were enriched at the site of infection (p = 0.002). While cytokine-expression profiles only showed minor differences between the groups, CTLA-4-expression levels on VZV-specific T cells from CSF and blood were significantly increased in VZV-related CNS-infections (p = 0.0002 and p<0.0001) and clearly identified VZV-related CNS-diseases (100% sensitivity and 100% specificity). Polyclonally stimulated T cells did not show any quantitative and phenotypical differences between the groups. Increased frequency and CTLA-4-expression of VZV-specific T cells from CSF or blood are specifically found in patients with VZV-related CNS-infection.