Increased rate of positive penicillin skin tests among patients with glioma: insights into the association between allergies and glioma risk

Abstract

Object Allergy and immunoglobulin E levels are inversely associated with glioma risk. Previous studies have focused on respiratory and food allergies, and little information is available regarding drug allergies. This study evaluated the rate of positive penicillin skin tests (PenSTs) and blood eosinophil counts in a large population of patients with glioma compared with nontumor controls to provide evidence for the relationship between drug allergies and glioma risk. Methods A retrospective case-control study was conducted in patients diagnosed with glioma (n = 913) between January 2004 and June 2013. The study patients were matched with nontumor controls (n = 1091) for age, sex, and date of admission to the hospital. Preoperative results of the PenST and eosinophil counts were obtained, and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using conditional logistic regression models, while a Kaplan-Meier analysis was used to assess overall survival. Results The percentage of positive PenSTs was higher among patients with glioma than in control subjects. The age-, sex-, and admission date–adjusted OR for positive versus negative PenSTs was 2.392 (95% CI 1.891–3.026). Eosinophil counts were also higher in glioma cases than in controls: the OR for eosinophil > 0.06 × 109/L versus ≤ 0.06 × 109/L was 1.923 (95% CI 1.608–2.301). There was no association between positive PenST/eosinophil counts and glioma grade or patient survival (n = 105). Conclusions In contrast to previously reported relationships between allergy and glioma, in the present study a significantly higher rate of positive PenSTs and higher eosinophil counts were found in patients with glioma than in nontumor controls. These results suggest a complex relationship between allergies and glioma development.