Molecular mimicry is one of the leading mechanisms in linking the role of microbiota in immune reactivity in autoimmune diseases and cancer.9, 10, 11, 12, 13 Reassuringly, it has been reported that microbiota-derived peptides resembling myelin basic protein (MBP) can activate autoreactive T cells in MS.14, 15, 16 MBP, along with proteolipid protein and myelin oligodendrocyte glycoprotein (MOG), are myelin antigens targeted by HLA-DR-restricted T cells, leading to MS development.1 The gene discussed is MOG; the disease is myeloid sarcoma.