Frequencies of IL-17⁺ Vγ9Vδ2 T cells in control subjects and in patients with bacterial meningitis. (A) Frequencies of IL-17–producing cells among Vγ9Vδ2 T cells from the peripheral blood of adult healthy donors (A-HC; n = 30), control children (C-HC; n = 8), and children affected by bacterial meningitis (Men; n = 12) on short-term stimulation with antigen (IPP). (B) The frequency of IL-17⁺ Vγ9Vδ2 T cells in the peripheral blood of children affected by bacterial meningitis (n = 12), before and after successful therapy, determined on antigen stimulation, as above described. (C) Frequencies of IL-17⁺ Vγ9Vδ2 T cells in the cerebrospinal fluid (CSF) of control children (HC-CSF; n = 8) and children affected by bacterial meningitis (Men-CSF; n = 12) on short-term stimulation with antigen (IPP). *P < .001 compared with all other groups.