New Discovery, Immune Cells in Cranial Bone Marrow Combat Glioblastomas: Study

In a recent study published in the journal Nature Medicine, researchers examine clinical glioblastoma and benign intracranial samples to determine the presence and function of immune cells in the brain.

The brain is considered an 'immune-privileged' organ with minimal immunological activity. However, recent research has revealed the presence of both innate and adaptive immune cells in areas such as the choroid plexus, meninges, and dural sinuses. The presence of immune cells at the interface between the central nervous system (CNS) and the rest of the body enables information to be conveyed from the brain via interstitial, cerebrospinal, and lymphatic fluids.

The disruption of the neuro-immune barrier may be implicated in malignant diseases, such as glioblastoma; however, immune checkpoint inhibitors have been associated with limited efficacy in treating glioblastomas. Systemic immunosuppression and intrinsic, adaptive, and acquired immunotherapy resistance may prevent these immunotherapies from successfully reaching brain tumours.

Clinical samples are collected from patients with grade four isocitrate dehydrogenase (IDH)-wildtype glioblastoma who had not undergone chemotherapy or radiation. Post-surgical CT scans were performed within 24 hours of sample collection, while MRI scans were done within 72 hours. To visualise and quantify CXCR4-expressing cells in the cranial bone and tumour tissues, clinical CXC chemokine receptor 4 (CXCR4) radiolabeling was integrated with PET-CT imaging data.

A total of 19 glioblastoma patient samples were analyzed and compared with samples obtained from five patients with non-malignant intracerebral disease. Active lymphoid tissue populations were identified in cranial bone marrow at the initial diagnosis of glioblastoma tumours. The combination of CXCR4 radiolabeling with PET-CT imaging was found to be highly effective for investigating immune cell dynamics within brain tissues.

The study sheds light on the behavior of T-cell populations, especially cytotoxic and memory T-cells, within the brain and their role in cancerous environments. Further research is essential to fully understand the immune landscape of glioblastomas and to create more targeted and effective treatments. Additionally, employing CCCR4 radiolabeling in PET-CT imaging presents a new method for tracking and visualizing immune cell dynamics in glioblastoma patients throughout their treatment.

References: Dobersalske, C., Rauschenbach, L., Hua, Y. et al. (2024). Cranioencephalic functional lymphoid units in glioblastoma. Nature Medicine. doi:10.1038/s41591-024-03152-x