It is an unsolved quirk of the immune system that the cell type that confers active immunity and incites inflammation (the T cell) and the cell type that dampens these processes (the regulatory T cell) arise from the same parent cells: T cell precursors in the bone marrow. Indeed, aside from very subtle distinctions in genetic markers, T cells and T reg cells are anatomically indistinguishable. And yet they are functionally complimentary. Immunity and its opposite are twinned: the Cain of inflammation conjoined with the Abel of tolerance. Sometime in the future, we will understand why
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