If the decreased frequency of LCL specific T cells in the blood were to be attributed solely to sequestration within the CNS, it would beg the question why EBV infected B cells accumulate in the CNS in the first place and why are they not eliminated by EBV specific CD8+ T cells, given that we have shown that EBV infected B cells of patients with MS can be killed by their own EBV specific CD8+ T cells. This evidence concerns the gene CD8A and myeloid sarcoma.