X-ray irradiation negatively affects immune responses in the lymphatic network

Area of Science:

• Oncology
• Immunology
• Radiology

Background:

• Immune checkpoint inhibitors are a promising cancer therapy, often combined with radiotherapy.
• Understanding radiotherapy's effects on lymphatic system and antigen presentation is vital for optimizing cancer treatment.

Purpose of the Study:

• To investigate the impact of X-ray irradiation on lymphatic vessels and high endothelial venules (HEVs) in sentinel lymph nodes.
• To evaluate changes in lymphatic drainage and immune cell trafficking post-irradiation.

Main Methods:

• Mice hindlimbs were irradiated with varying X-ray doses (2, 10, 30 Gy).
• X-ray computed tomography (CT) with gold nanoparticles assessed lymph vessel diameter and flow.
• Immunohistochemistry analyzed HEV morphology and density using MECA-79 expression.

Main Results:

• Irradiation dose-dependently increased lymph vessel diameter and reduced lymphatic drainage.
• High endothelial venule (HEV) density decreased, with altered morphology observed in irradiated lymph nodes.
• X-ray exposure impaired lymphatic function and reduced HEV area density, affecting immune response pathways.

Conclusions:

• X-ray irradiation negatively affects lymphatic vessels and HEVs in lymph nodes.
• These changes may compromise antigen presentation, a critical factor in cancer immunity.
• Strategic planning of sentinel lymph node irradiation is essential for cancer treatment efficacy.