Genetic inhibition of NFATC2 attenuates asparaginase hypersensitivity in mice.

The family of nuclear factor of activated T cells (NFAT) transcription factors plays a critical role in mediating immune responses. Our previous clinical pharmacogenetic studies suggested that NFATC2 is associated with the risk of hypersensitivity reactions to the chemotherapeutic agent L-asparaginase (ASNase) that worsen outcomes during the treatment of pediatric acute lymphoblastic leukemia. We therefore hypothesized that the genetic inhibition of NFATC2 would protect against the development of anti-ASNase antibodies and ASNase hypersensitivity. Our study demonstrates that ASNase-immunized NFATC2-deficient mice are protected against ASNase hypersensitivity and develop lower antigen-specific and total immunoglobulin E (IgE) levels compared with wild-type (WT) controls. Furthermore, ASNase-immunized NFATC2-deficient mice develop more CD4+ regulatory T cells, fewer CD4+ interleukin-4-positive (IL-4+) cells, higher IL-10/TGF-ß1 levels, and lower IL-4/IL-13 levels relative to WT mice. Basophils and peritoneal mast cells from ASNase-immunized, but not naïve, NFATC2-deficient mice had lower FcεRI expression and decreased IgE-mediated mast cell activation than WT mice. Furthermore, ASNase-immunized, but not naïve, NFATC2-deficient mice developed less severe shock than WT mice after induction of passive anaphylaxis or direct histamine administration. Thus, inhibition of NFATC2 protects against ASNase hypersensitivity by impairing T helper 2 responses, which may provide a novel strategy for attenuating hypersensitivity and the development of antidrug antibodies, including to ASNase.