Features of immune status in patients with metastatic and glial brain tumors at the preparatory stage of radiotherapy

Abstract

Background. Studies carried out in recent decades have shown that immune cells are essential participants in the cancer process as well as cancerrelated inflammation. Focus has been increased on understanding the way how immune cells affect a tumor at different stages of the disease: early neoplastic transformation, clinically detected tumors, metastatic spread, and at surgery and radiotherapy stages.
 Purpose – assessing the status of the immune system in patients with brain tumors before radiation therapy and radiosurgery and comparing the features of immunity in metastatic and glial brain tumors.
 Materials and methods. The study presents the immunogram findings of 61 patients. Out of those: 18 patients with primary glial tumors and 23 patients with secondary metastatic tumors to the brain. The outcomes of 20 conditionally healthy non-cancer patients are presented as a control group. The age of patients is 24–75. All patients were histologically diagnosed with the tumor. Surgery was performed 1.0–3.0 years before the examination. Assessment of the immune system in patients with brain tumors was performed taking into account the cellular, humoral and phagocytic component of innate immunity. When assessing cellular immunity, the relative and absolute count of major lymphocyte subpopulations, such as CD3+ – general T-lymphocytes, CD4+ – T-lymphocytes-helpers, CD8+ – cytotoxic lymphocytes, CD16+ – natural killer lymphocytes, CD19+-B-lymphocytes, were calculated. Determining the humoral parameters included an assessment of quantitative values of IgG, IgM and IgA. Quantitative assessment of the phagocytic component of innate immunity included phagocytic activity of neutrophils (i. e. NBT test (Nitroblue Tetrazolium test), inducing (Zymosanum) and spontaneous neutrophil myeloperoxidase activity).
 Results. When comparing the immune parameters of the number of T- and B-subpopulations of lymphocytes in patients with primary malignant brain tumors and secondary metastatic tumors, no statistically significant difference has been detected between these params. Glioblastomas show higher levels of СD4+- and CD8+-lymphocytes in comparison with other tumour groups as well as higher levels of IgG and IgA than in other tumors, while IgM concentration is almost at the same level in three groups of patients. There is a tendency for reducing IgG and IgM level in the blood of patients with metastatic tumors. Both groups of cancer patients under study show inhibition of myeloperoxidase activity of neutrophils in the setting of maintaining the function of NBT cell activity.
 Conclusions. According to the findings obtained via studying immunological indicators of brain tumors, both metastatic and primary malignant glial ones, there are partial changes in various immune system components such as cellular, humoral and phagocytic activity. However, no statistically significant difference was detected between immune status indicators, that substantiates the need for further study of this issue. At the stage of preparation for radiation therapy, no significant changes in the immune system of the patients with brain tumors, that would make such treatment impossible and be consiered as one of contraindications, are observed.