The 2-Hydroxyiminostilbene Metabolite of Carbamazepine or the Supernatant from Incubation of Hepatocytes with Carbamazepine Activates Inflammasomes: Implications for Carbamazepine-Induced Hypersensitivity Reactions.

Although the pathophysiology of carbamazepine-induced idiosyncratic or hypersensitivity reactions is unclear, they are presumed to be immune mediated, involving a complex interaction between drug metabolism and activation of the immune system. Cell stress can be caused by reactive metabolites, and this has the potential to release damage-associated molecular patterns (DAMPs), which are responsible for activation of the immune system. Idiosyncratic drug reactions occur mainly in the liver because of its role in drug metabolism and reactive metabolite formation. DAMPs can activate inflammasomes, which may be a common mechanism by which DAMPs lead to an immune response. In the present study, we investigated whether carbamazepine induces the release of DAMPs by using human hepatocarcinoma functional liver cell-4 (FLC-4) cells for bioactivation of carbamazepine. THP-1 cells, a human macrophage cell line, were used for detecting inflammasome activation. We found that increased caspase-1 activity and production of interleukin-1 by THP-1 cells were caused by the supernatant from the incubation of carbamazepine with FLC-4 cells. In the supernatant, heat shock protein 60 was significantly increased. In addition, 2-hydroxyiminostilbene, which is a metabolite of carbamazepine, activated inflammasomes. These results suggest that the reactive iminoquinone metabolite can directly activate inflammasomes or that stressed hepatocytes cause the release of DAMPs, which are responsible for inflammasome activation. The activation of inflammasomes may be an important step in the immune system activation by carbamazepine, which can lead to hypersensitivity reactions in some patients. SIGNIFICANCE STATEMENT: A metabolite of carbamazepine, 2-hydroxyiminostilbene itself, and the damage-associated molecular patterns released from hepatocytes incubated with carbamazepine activated inflammasomes. The activation of inflammasomes may be an important step in the immune system activation by carbamazepine, which can lead to hypersensitivity reactions in some patients.