Immunologic status in children with brain tumors and the effect of therapy

Multidimensional modulation of systemic immune by neurosurgical tumor resection in patients with brain tumors

OBJECTIVES

Immune perturbation induced by tumor burden has been showed as the hallmark of brain tumors. To date, the vast majority of studies have focused heavily on local immune responses in the tumor microenvironment. Little is known about how the systemic immune macroenvironment is modulated by neurosurgical tumor resection in patients with brain tumors.

METHOD

Medical records from patients with brain tumors admitted to the Department of Neurosurgery at the National Cancer Center, Cancer Hospital of Chinese Academy of Medical Sciences between January 2021 and March 2022 were retrospectively reviewed. Forty-nine patients who have lymphocyte subsets, serum immunoglobulins, C-reactive protein, and complements levels before neurosurgical tumor resection and at least once test after surgery were included into the final analysis.

RESULTS

Postoperative CD3+ lymphocytes, CD4+ lymphocytes and CD4+ /CD8+ lymphocyte ratio presented bi-phasic changes, which indicated an initial decrease and a subsequent increase after neurosurgical tumor resection. Moreover, neurosurgical tumor resection induced a decrease in natural killer lymphocytes and an increase in B lymphocytes that persisted through the entire observation period after surgery. Meanwhile, significant changes in humoral immunity characterized by a decrease in immunoglobulins (IgA, IgG, and IgM) levels and an increase in the CRP level occurred after neurosurgical tumor resection. In addition, patients with postoperative infection complication had a lower preoperative CD4+ /CD8+ lymphocyte ratio.

CONCLUSIONS

These findings provide evidence that either cellular immunity or humoral immunity can be remodeled by neurosurgical tumor resection, and patients with disturbed systemic immunity have increased risk of infection after surgery.

T lymphocyte subsets and immunoglobulins in intracranial tumor patients before and after treatment, and based on histological type of tumors

It has been reported that nervous system and peripheral immune system communicate with each other and the peripheral immune status is depressed in some intracranial tumor (ICT) patients pre operatively. Little is known about the immune status of intracranial tumor patients during the post operative survival period. We thus investigated total T cells (CD 11+), helper/inducer (CD4+) T cells, suppressor/cytotoxic (CD8+) T cells, B cells (CD19+) and serum immunoglobulins in peripheral blood in certain ICT patients before and after treatment, and based on the histological type of the tumors. Post treatment analysis were conducted 30 days after surgical removal of tumor tissue in benign brain tumor patients and 30 days after chemo therapy (CT)/radiotherapy (RT) following surgical removal of tumor tissue in malignant brain tumor patients. Decreased CD11+, CD4+ and increased CD8+ T cell counts were observed in both benign and malignant tumor cases before treatment compared with control subjects. After treatment, CD4+ T cell count increased and CD8+ T cell count decreased than their pre treatment levels. Serum IgA and IgG levels were decreased in both benign and malignant brain tumor patients before treatment than in control subjects. Serum IgM level has been increased in both benign and malignant tumor patients before and after treatment than in control subjects. Anaplastic malignant astrocytoma, medulloblastoma and glioblastoma multiforme patients showed higher IgM level than astrocytoma, meningioma and ependymoma patients. In conclusions, the depressed host cellular immunity in benign and malignant tumor patients before treatment may be due to the changes in CD4+ and CD8+ counts in addition to tumour specific immunosuppressive factors. Treatment procedures such as surgery, CT and RT may play certain role in the post operative depressed immunosuppression in malignant tumor patients. Humoral immune mechanism (CD19+) in the ICT patients was less markedly affected.

Impact of localized radiotherapy on blood immune cells counts and function in humans

Immune cells subsets were prospectively analyzed after localized radiotherapy (LRT). LRT reduced the levels of all lymphocyte subsets, with B-cells and naive T-cells being most sensitive. Lymphocyte function was suppressed, but still within the normal range. Rapid recovery of cytotoxic T-cells/natural killer cells after LRT and the functional suppression within normal levels explains the low incidence of infections after LRT.