Predominance of Vγ9/Vδ2 T lymphocytes in the cerebrospinal fluid of children with tuberculous meningitis: Reversal after chemotherapy

Abstract

Background: We analyzed the γδ T cell composition and responses in the peripheral blood and cerebrospinal fluid (CSF) of children affected by tuberculous meningitis (TBM) and in control children. Materials and Methods: Peripheral blood and CSF samples were stimulated with different phosphoantigens and IL-2, and expansion of Vγ/Vδ2 T cells assessed by FACS analysis. Vγ9/Vδ2 lines were obtained by culturing CSF or peripheral blood mononuclear cells (PBMC) in vitro with phosphoantigens and IL-2 for 2 months, and tested for proliferation and cytokine production in response to phosphoantigens. Vδ2(D)Jδ junctional sequence length was assessed by PCR. Results: The repertoire of γδ T cells from the CSF of TBM patients was characterized by the predominance of Vγ9/Vδ2 T lymphocytes, which accounted for >80% of γδ T cells. Vγ9/Vδ2 cells from the CSF of TBM children responded to different synthetic and natural (mycobacterial) phosphoantigens and produced discrete amounts of IFN-γ and TNF-α. The in vitro expansion of Vγ9/Vδ2 T cells from CSF and peripheral blood of TBM patients prominently decreased following chemotherapy, and similarly, the proportion of ex vivo unstimulated Vγ9/Vδ2 T cells in CSF of TBM patients decreased to levels detected in the CSF of control subjects. Vδ2 CDR3 TCR analysis showed that the remaining Vδ2 cells in the CSF of TBM patients were still polyclonal. Conclusions: These findings are consistent with an involvement of Vγ9/Vδ2 T cells in TBM.