Retinoic-acid-receptor-related orphan nuclear receptor alpha is required for natural helper cell development and allergic inflammation.

Natural helper (NH) cells are innate lymphoid cells (ILCs) that produce T helper-2 (Th2)-cell-type cytokines in the lung- and gut-associated lymphoid tissues. Currently, the lineage relationship between NH cells in different tissues and between NH cells and interleukin-22 (IL-22)-producing retinoic-acid-receptor-related orphan receptor (ROR)γt-positive ILCs is unclear. Here, we report that NH cells express RORα, but not RORγt.