May regulate the expression of IL-2, IL-6, and other cytokines through regulation on NF-kappa-B activity. Functions in the regulation of inflammatory responses. May also regulate TCR-induced negative selection of thymocytes.IκBNS, the nuclear IκB-like protein encoded by Nfkbid, is required for the development of marginal zone and peritoneal B-1 B cells and additionally required for extrafollicular antibody responses to T-independent and -dependent immunogens.IκBNS has been identified as a member of the IκB family of NF-κB inhibitors, which undergoes induction upon TCR signaling. IκBNS mediates both positive and negative gene regulation, depending on individual cell type and/or cytokine.