Cytokine release of a keratinocyte model after incubation with two different Viscum album L extracts.

When injected subcutaneously, extracts from the white berry mistletoe (Viscum album L) lead to a dose-dependent local inflammatory reaction at the injection site. From in vitro investigations with V album extracts, the release of proinflammatory cytokines from peripheral blood mononuclear cells and from a human skin model (Skin(2) model; Advanced Tissue Sciences, La Jolla, CA) is known. This shows dose dependence for mistletoe lectin-I in the range of 0.02 ng/mL to 10.0 ng/mL. In this study, an investigation was conducted of which cytokines are released in the skin by the mistletoe lectin-standardized mistletoe extracts Viscum album QuFrF (VaQuFrF) and Iscador Qu Spzial (IQuS) (Institute Hiscia, Arlesheim, Switzerland) and whether dose dependency exists. The model used for this study is the multilayered skin model EpiDerm (MatTek Corporation, Ashland, MA), which consists of multilayered keratinocytes. The viability of the cell culture was measured after incubation with 0.01, 0.1, 0.2, 0.3, 0.5, and 15.0 ng/mL VaQuFrF or 0.01, 0.1, 0.2, 0.3, 0.5, 5.0, and 15.0 ng/mL IQuS. The release of interleukin (IL)-1alpha, IL-2, IL-6, IL-8, IL-10, IL-12p(40+70), IL-12p(70), tumor necrosis factor-alpha (TNFalpha), interferon (IFN)-alpha, IFNgamma, granulocyte macrophage-colony stimulating factor, and RANTES was determined after incubation with 0.5 ng/mL of IQuS ng/mL and VaQuFrF. The dose dependency of the release of IL-1alpha and IL-6 after incubation with 0.5 and 15.0 ng/mL VaQuFrF or 0.5 ng/mL, 5.0 ng/mL, and 15.0 ng/mL IQuS and that of the release of IL-1alpha, IL-2, IL-6, IL-10, and TNFalpha after incubation with 0.01 ng/mL, 0.1 ng/mL, 0.2 ng/mL, 0.3 ng/mL, and 0.5 ng/mL VaQuFrF or IQuS were determined. A dose-dependent decrease of cellular viability and an increase of IL-1alpha, IL-6, and TNFalpha as well as the release of IL-8 could be demonstrated. These results are compatible with the hypothesis that the subcutaneous injection of VaQuFrF and IQuS leads to a release of proinflammatory cytokines at the injection site.