Given the systemic antibody responses against flagellated bacteria observed in both CD and ME/CFS, the question arises as to which specific types of flagellins (stimulator, evader, or silent flagellins) and to what regions of the flagellin protein (such as the N-terminal nD1-domain containing TLR5 motif or the C-terminal D0 domain-located allosteric binding site essential for receptor activation) these antibodies are directed. Here, TLR5 is linked to myalgic encephalomeyelitis/chronic fatigue syndrome.