Analysis of the effect of RM-10™ preparations on the immune system

The effect of RM-10, a nutraceutical preparation, on the immune system was investigated. This nutraceutical preparation is known to improve the immune status of patients suffering of diverse conditions. RM-10, at concentrations up to 100 μg/ml did not affect the in vitro basal and PHA-induced proliferation of lymphocytes. A slight inhibition of the PHA-induced lymphocyte proliferation was noted at concentrations above 100 μg/ml, this phenomenon being associated with cell toxicity. As well, no effect of addition of RM-10 on PHA-induced IL-2 and gamma-interferon release from lymphocytes was noted. These results indicated that addition of RP-10 to the incubation medium has no direct effects on human lymphocyte in vitro. By contrast, RM-10 preparations in the dose range of 1 to 20 μg/ml, increased by 15 to 20% the proliferation of human lymphocytes stimulated with allogeneic cells. However, due to intra-experiment variations, this difference is not statistically significant. Such an effect of RM-10 might be related to an influence of accessory cells involved in the mixed lymphocyte reaction. A marked effect of RM-10 was noted on NK cell activity at concentrations ranging from 1 to 25 μg/ml. At higher concentrations of RM-10, a direct toxic effect on NK cells was noted. It is noteworthy that the effects of RM-10 on mixed lymphocyte reaction and NK cell activity are noted at concentrations ranging from 1 to 25 μg/ml. This indicates that some active components are present in the extract. However, given the fact that a decrease in the activity is observed when increasing the concentration suggests that additional components of the extract are cytotoxic, and interfere with the effect. Marked effects of addition of RM-10 preparations on both the basal (no LPS added) and on the LPS-induced IL-1, IL-6 and TNF-α release from monocytes were noted. This increase was maximal at the 25 μg/ml and a return to basal values was noted at higher concentrations. These results suggest the presence of substances that both increase (at low concentration of the extract) and possibly decrease (at higher concentration of the extract) monokine production by LPS-stimulated monocytes. However, the effect of the RM-10 extract noted at low concentrations (i.e. below 25 μg/ml) suggests the presence of highly active components. At concentration above 25 μg/ml, RM-10 evokes a dose-dependent decrease in cell proliferation of K562 cells. This effect is maximal at the highest concentration investigated (i.e. 200 μg/ml). In conclusion, the present results indicate that RM-10 rather acts on accessory cells like monocytes and macrophages than on lymphocytes. RM-10 appears to primarily act on cytokine release, at least on the basis of the experiments reported. Further studies, using sub fractions of the RM-10 preparation, are required to assess the immunomodulatory activity of this nutraceutical preparation.