Genetic variants associated with immune-mediated liver injury from checkpoint inhibitors.

Background: The clinical features, liver histology, and genetic variants in 57 patients with moderate to severe immune-mediated liver injury from checkpoint inhibitors (ILICI) are presented.

Methods: Between 2010 and 2022, 57 high-causality ILICI cases were enrolled in the Drug-Induced Liver Injury Network. HLA and selected candidate gene variants were tested for association with ILICI risk compared to the general population and other DILI controls.

Results: The 57 high-causality cases were attributed to pembrolizumab (16), ipilimumab (15), ipilimumab and nivolumab (13), and other immune checkpoint inhibitors (13) and occurred at a median of 72 days after the first infusion. Median age was 57.8 years, 66% male, and 89% were non-Hispanic Whites. At DILI onset, 53% had hepatocellular, 35% mixed, and 15% cholestatic, with younger patients more likely to have hepatocellular injury. The incidence of ANA, smooth muscle antibody, and elevated IgG levels was low (17%, 23%, and 0%), but corticosteroids were given to 86%. Microgranulomas and hepatic steatosis were seen in 54% and 46% of the 26 liver biopsies, respectively. The HLA alleles associated with autoimmune hepatitis were not over-represented, but 2 host immune response genes (EDIL3 and SAMA5A) and 3 other genes (GABRP, SMAD3, and SLCO1B1) were associated with ILICI (OR: 2.08-2.4, p<0.01).

Conclusions: ILICI typically arises within 12 weeks of initiating immunotherapy and is self-limited in most cases. Genetic variants involved in host T-cell regulation and drug disposition were identified, implicating these pathways in the pathogenesis of ILICI. If validated, these findings could lead to improved diagnostic instruments and possible treatments for ILICI.