CD4+CD28- T cells were subsequently detected in MS brain biopsies, where they displayed a cytotoxic phenotype and expressed CX3C chemokine receptor 1 (CX3CR1), which binds to chemokine (C-X3-C motif) ligand 1 (CX3CL1) (22). The gene discussed is CX3CR1; the disease is myeloid sarcoma.