Targeting Immune Modulators in Glioma While Avoiding Autoimmune Conditions

SIMPLE SUMMARY: Glioblastoma multiforme is a futile disease usually leading to the patient’s death within one year post-diagnosis; therefore, novel treatment options are desperately needed. In this regard, activation of the inert immune system has moved into focus in recent years. Malignant brain tumors, as well as autoimmune diseases, elicit aberrant immune responses. In this way, glioma escapes the host’s immune system and, thus, activation of the immune response in order to reduce tumor tolerance can serve as an alternative treatment option. Immune checkpoint modulators in combination with traditional therapies have gained attention in both glioma and autoimmune diseases. In this review, we highlight ongoing or completed clinical trials that target immune modulators in these diseases. ABSTRACT: Communication signals and signaling pathways are often studied in different physiological systems. However, it has become abundantly clear that the immune system is not self-regulated, but functions in close association with the nervous system. The neural–immune interface is complex; its balance determines cancer progression, as well as autoimmune disorders. Immunotherapy remains a promising approach in the context of glioblastoma multiforme (GBM). The primary obstacle to finding effective therapies is the potent immunosuppression induced by GBM. Anti-inflammatory cytokines, induction of regulatory T cells, and the expression of immune checkpoint molecules are the key mediators for immunosuppression in the tumor microenvironment. Immune checkpoint molecules are ligand–receptor pairs that exert inhibitory or stimulatory effects on immune responses. In the past decade, they have been extensively studied in preclinical and clinical trials in diseases such as cancer or autoimmune diseases in which the immune system has failed to maintain homeostasis. In this review, we will discuss promising immune-modulatory targets that are in the focus of current clinical research in glioblastoma, but are also in the precarious position of potentially becoming starting points for the development of autoimmune diseases like multiple sclerosis.