Using high-throughput sequencing of TCR-β chains in CSF and blood, Lossius and colleagues (60) also found selective enrichment of EBV-reactive CD8 T cells mainly recognizing EBV lytic proteins, but not CD8 T cells recognizing influenza A virus, in the CSF of MS patients compared to patients with other inflammatory neurological diseases. The gene discussed is CD8A; the disease is myeloid sarcoma.