After primary encephalitis induction, the proportion of hippocampal CD8+ T cells amongst total hippocampal T cells increased from 25.0% ± 24.0% during the acute phase to 71.6% ± 29.8% during the recovery phase and 89.2% ± 14.8% after completion of the long-term follow-up. The gene discussed is CD8A; the disease is encephalitis.