We found that the number of B. burgdorferi B31-specific IFN-γ-secreting T cells/2.5 × 105 PBMCs in peripheral blood was significantly elevated in active Lyme neuroborreliosis patients, treated Lyme neuroborreliosis patients, and healthy individuals treated for early manifestations of LB in the past compared to untreated healthy individuals (P ≤ 0.016). The gene discussed is IFNG; the disease is Lyme disease.