Radiation therapy-induced reactive oxygen species specifically eliminates CD19(+)IgA(+) B cells in nasopharyngeal carcinoma

PURPOSE: Nasopharyngeal carcinoma (NPC) is one of the most common head and neck cancers and is thought to be related to the mucosal immune system. Radiation therapy (RT) is the primary treatment for NPC due to the high radiosensitivity of cancer cells. However, little is known about the impact of RT on the mucosal immune system. PATIENTS AND METHODS: In this study, the expression of immune markers CD19, CD24, CD27, CD8, and IgA before and after RT, were analyzed using flow cytometry. Cytokines were assessed using the enzyme-linked immunosorbent assay. Reactive oxygen species (ROS) was assayed by flow cytometry and fluorescence staining using 2ʹ,7ʹ -dichlorofluorescein diacetate. RESULTS: We found that primary NPC patients had a significant increase in CD19(+)CD138(−)IgA(+) B cells, which was then decreased after RT. Interestingly, the changes in CD19(+)CD138(−)IgA(+) B cell frequency was accompanied by corresponding frequency changes in cytotoxic T cells (CTL), which are powerful anti-tumor lymphocytes. Mechanistically, we found that ROS release during RT specifically eliminated CD19(+)CD138(−)IgA(+) B cells. CONCLUSION: These findings suggest that RT may regulate the immune system and opens up new avenues for the utilization of immune-radiotherapy in NPC.