Conclusion
A significant increase of peripheral natural killer cells and interferon-gamma (INF-γ) after 4 weeks of gefitinib treatment (P=0.005 and 0.02, respectively). In addition, circulating interleukin (IL)-6 was significantly decreased, especially in patients sensitive to gefitinib (P<0.001). Higher levels of IL-6 at baseline independently correlated with poorer progression-free survival. Experiments with NSCLC specimens illustrated that PD-L1 expression were downregulated after 4 weeks of gefitinib treatment. In summary, it was found that gefitinib treatment can alter circulating cytokines and lymphocytes. Dynamic changes of circulating lymphocytes, cytokines, and even PD-L1 IHC expression around gefitinib treatment support the specific immunomodulatory effect of this agent for advanced NSCLC.
Methods
Peripheral blood samples were collected from 54 patients at baseline and after 4 weeks of gefitinib treatment. Circulating lymphocyte populations and cytokine levels were measured. Pilot investigation of the impact of gefitinib on programmed cell death ligand-1 (PD-L1) expression was conducted by immunohistochemistry (IHC).