Increase of plasma IgE during treatment correlates with better outcome of patients with glioblastoma

Abstract

Background: Previous studies have shown that glioma patients have lower blood IgE levels than controls. To evaluate its potential as a surrogate biomarker for glioma, we measured plasma IgE levels in glioma patients and healthy controls, and correlated them with clinicopathological factors and the patients' outcome.

Methods: We used enzyme-linked immunosorbant assay (ELISA) to determine the plasma IgE levels of 25 normal subjects and 252 glioma patients (85 patients with grade II glioma, 46 patients with grade III glioma, and 121 patients with glioblastoma). We also collected longitudinal plasma samples from glioblastoma patients and compared the plasma IgE levels before operation, one week after operation, in the middle of radiotherapy, after two cycles of chemotherapy, and after recurrence. The correlations between plasma IgE levels and the outcomes of the patients were determined.

Results: Plasma IgE levels were significantly lower in glioma patients (P = 0.004); patients with low-grade glioma have lower IgE levels than patients with high-grade glioma do (P = 0.029). In 24 patients with both preoperative plasma and two-cycle chemotherapy plasma samples, IgE levels increased after successful removal of the tumor (P = 0.021), and the increase correlated with the patients' survival (increase > 100 ng/ml vs. ≤ 100 ng/ml, 127.5 weeks vs. 62.3 weeks. P = 0.012, log-rank). Plasma IgE level increase of > 100 ng/ml has a specificity of 80% and a sensitivity of 78% to predict the patients' long survival (> 18 months).

Conclusions: Our results suggest that plasma IgE level correlates with clinical and pathological factors in glioma patients. It has the potential to be a biomarker for glioma patients.