Interleukin-6 plasma levels are modulated by a polymorphism in the NF-κB1 gene and are associated with outcome following rituximab-combined chemotherapy in diffuse large B-cell non-Hodgkin lymphoma.

Peripheral blood cytokines are known prognostic parameters in diffuse large B-cell lymphoma (DLBCL) treated with chemotherapy, but their role after the introduction of rituximab is unknown. Seven polymorphisms in the promoter regions of IL-6, IL-10 and NF-κB1 genes were assessed in 167 patients with DLBCL and 99 controls and correlated with interleukin-6 (IL-6) and IL-10 plasma levels. Outcome was analyzed in 137 patients treated with rituximab-based chemotherapy. The NF-κB1 - 94ATTG deletion was associated with increased IL-6 and IL-10 in DLBCL. High IL-6 concentration correlated with unfavorable prognostic factors included in the international prognostic index (IPI) and predicted for inferior progression-free (p = 0.007) and overall survival (p = 0.02). IL-6 levels remained a significant outcome predictor also including IPI as a covariate (p = 0.006 for progression-free survival). Our data suggest that the NF-κB1 genetic background influences IL-6 production in DLBCL, and that high IL-6 concentration is an independent prognostic factor also in the "rituximab era."