Proteomic and Metabolomic Analysis of Immune-Related Adverse Events in Patients Treated with PD-1 Inhibitors

As a class of immune checkpoint inhibitors (ICIs), programmed cell death protein-1 (PD-1) blockade has demonstrated remarkable efficacy in the treatment of various malignancies. However, their clinical application is constrained by the high incidence of immune-related adverse events (irAEs), which arise from nonspecific immune activation and can affect multiple organ systems, with severe cases posing life-threatening risks. This study integrated high-throughput proteomic and metabolomic analyses to systematically characterize the molecular features associated with irAEs in cancer patients receiving PD-1 inhibitor therapy. The results showed that, following the first treatment, patients who developed irAEs exhibited potential involvement of the NF-κB pathway, along with lower baseline levels of SNRPA and higher expression of CD63. Metabolomic analyses further revealed that the kynurenine/tryptophan ratio was significantly elevated in the irAE group both at baseline and post-treatment compared with patients who did not develop irAEs. In addition, significant differences in the abundance of specific lipids were observed between the two groups prior to the administration of immunotherapy. Our findings provide exploratory insights into immune and metabolic alterations associated with PD-1 blockade treatment and may help generate hypotheses for future studies on early irAE risk assessment in cancer patients undergoing PD-1 blockade therapy.