Human regulatory cells miss their target

T_reg cells are essential for 'tuning' appropriate immune responses; however, the extent to which their numerical or functional impairment contributes to allergy in humans is unclear. In Cell, Scheffold and colleagues use a technique for isolating and functionally examining minute populations of antigen-reactive human T cells to investigate the role of T_reg cells in allergy. In normal volunteers, both conventional T cells and T_reg cells are found to react to self, non-self and commensal antigens. People allergic to aeroantigens also show normal T_reg cell numbers and functionality but fail to control allergic responses of the T_H2 subset of helper T cells. This relative inability to suppress allergen-specific responses arises because the T_reg cells and T_H2 cells target different sets of antigens. The data suggest that rather than there being an inherent wholesale loss of T_reg cell functionality, allergy can arise by a failure of the suppressive cells to overlap in time and/or space with the pathogenic T cells.

Cell (20 October 2016) doi:10.1016/j.cell.2016.09.050