Peripheral blood CD86-positive plasmacytoid dendritic cells and immune-related adverse events in lung cancer patients

Background: The immune-related adverse events (irAEs) is unpredictable. Peripheral blood mononuclear cell (PBMC) profiles have potential for predicting irAEs. Methods: PBMCs were measured using multicolor flow cytometry before and at weeks 2 and 8 after the immune checkpoint inhibitors (ICIs) in lung cancere patients. Results: Sixteen patients were eligible for the analysis. The irAEs occurred in 6 (37.5%) patients. Patients with irAEs demonstrated higher levels of CD86+plasmacytoid dendritic cells (pDCs) at baseline and weeks 2 and 8 after the ICIs than patients without irAEs (p = 0.005, 0.038, and 0.050, respectively). Higher levels of natural killer (NK) cells were significantly associated with overall objective response (p = 0.024). Conclusions: Higher levels of CD86+pDCs at baseline and the reduction at 2 and 8 weeks after the ICIs were associated with the occurrence of irAEs. Higher levels of NK cells were associated with therapeutic efficacy. Measurements of PBMCs may be useful for predicting the efficacy and safety of ICIs.