The Viscum album extract Iscador P does not cause an autocrine interleukin-6 loop in B-non-Hodgkin's lymphoma cell lines

Background: Single cases of clinical observations suggest the efficacy of the Viscum album (VA) extract Iscador P in the treatment of follicular B-Non-Hodgkin's Lymphoma (B-NHL). A previously published study aroused a controversial dispute as it indicated that IL-6 serum levels are elevated following i.v. VA treatment. Increased IL-6 levels have been shown to promote the progression of B-cell neoplasia such as B-NHL. Objective of this study was to investigate whether the VA extract influences the expression of IL-6 and its receptor components in follicular B-NHL cell lines. Methods: Follicular B-NHL cell lines (WSU-NHL, DoHH-2) were incubated with clinically relevant doses of VA extract for up to 3 days. At specified time points (6, 24, 48, 72 h) samples were taken and the expression of IL-6 and its receptor components were analysed by real-time-RT-PCR, flow cytometry and ELISA. Results: Treatment of follicular B-NHL cell lines with VA extract did not alter the expression level of IL-6 and its' receptor components at any time and with any of the applied VA extract concentrations. Conclusions: Clinically relevant doses of the VA extract do not trigger an autocrine or paracrine IL-6 loop nor do they initiate IL-6 trans-signal ling in follicular B-NHL cell lines.