Involvement of oral bacteria and oral immunity as risk factors for chemotherapy-induced fever with neutropenia in patients with hematological cancer.

The aim of this study is to investigate the association between chemotherapy-induced fever with neutropenia less than 1500/μL (FwN) and oral bacteria and/or oral immunity in patients with hematological cancer. Thirty-two patients with hematological cancer were enrolled in the study. Secretory immunoglobulin A (sIgA) in saliva and the anaerobic bacteria in tongue coating of each subject were assessed before the first chemotherapy. Eleven subjects had an onset of FwN and 21 subjects did not during the observation periods. It was revealed by the Cox-proportional hazard model analysis that the levels of sIgA were low (HR 0.98, p < 0.05) and the rate of Fusobacterium nucleatum [F. nucleatum count per total bacterial count (%)] was high (HR 1.65, p < 0.05) in patients with FwN onset. Using ROC curve analysis, the optimal cutoff point based on the AUC in the F. nucleatum/sIgA ratio was 0.023, and this model had a 78.4% probability (p < 0.01). The risk of FwN onset was also significantly higher among the group of ≥ 0.023 F. nucleatum/sIgA ratio (HR 66.06, p < 0.01). These results suggest that the rate of F. nucleatum and the levels of sIgA at baseline might be related to FwN onset as risk factors.