Reply to Krämer et al.: Human natural killer (NK) cell inhibition by IL28A

Following our PNAS paper linking type 3 IFN and NK cells (1), Kramer et al. have performed experiments in which they find low IL28R expression on NK cells and no response to either IL28A or IL28B in terms of activation NK cell cytotoxicity or cytokine production (2). Kramer et al. (2) interpret their data to suggest that λ-IFNs do not directly act on NK cells to modify their functional activity.