Predominance of V gamma 9/V delta 2 T lymphocytes in the cerebrospinal fluid of children with tuberculous meningitis: Reversal after chemotherapy

Background: We analyzed the gamma delta 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 wit h different phosphoantigens and IL-2, and expansion of V gamma 9/V delta 2 T cells assessed by FAGS analysis. V gamma 9/V delta 2 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 cy tokine production in response to phosphoantigens. V delta 2(D)J delta junct ional sequence length was assessed by PCR. Results: The repertoire of gamma delta T cells from the CSF of TBM patients was characterized by the predominance of V gamma 9/V delta 2 T lymphocytes , which accounted for >80% of gamma delta T cells. V gamma 9/V delta 2 cell s from the CSF of TBM children responded to different synthetic and natural (mycobacterial) phosphoantigens and produced discrete amounts of IFN-gamma and TNF-alpha. The in vitro expansion of V gamma 9/V delta 2 T cells from CSF and peripheral blood of TBM patients prominently decreased following ch emotherapy, and similarly, the proportion of ex vivo unstimulated V gamma 9 /V delta 2 T cells in CSF of TBM patients decreased to levels detected in t he CSF of control subjects. V delta 2 CDR3 TCR analysis showed that the rem aining V delta 2 cells in the CSF of TBM patients were still polyclonal. Conclusions: These findings are consistent with an involvement of V gamma 9 /V delta 2 T cells in TBM.