Using autopsied brain tissues from patients with progressive MS (Supplemental Table 1), demyelinated frontal white matter (WM) lesions were shown to exhibit myelin loss (Luxol Fast Blue ; LFB), abundant CD68-immunopositive macrophages/microglia, and CD3-immunopositive T lymphocytes (Supplemental Figure 2Aiv–ix). The gene discussed is CD68; the disease is myeloid sarcoma.