Recently, sharing of predominant T‐cell clones between CNS lesions, CSF, and blood CD8+ T cells was found in three MS patients when the TCR β‐chain repertoire was analyzed using a multiplex amplification approach for V‐ J genes.22 Clonally infiltrating, expanded CD8+ and CD4+ T‐cell in demyelinating MS lesions pattern II were also identified in the CSF compartment of MS patients after ex vivo culture expansion.23 The gene discussed is CD4; the disease is myeloid sarcoma.