The immunomodulatory properties of in vitro immunoglobulins are dose-dependent

Objectives - The mechanism by which intravenous immunoglobulins ( immunoglobulin G, IgG) exert their beneficial effect on multiple sclerosis ( MS) is unknown. Furthermore, there is uncertainty about the optimal dosage of IgG. Therefore, we investigated the influence of different IgG dosages on cytokine production in MS. Materials and methods - Twenty-five MS patients and 15 healthy controls were enrolled. We measured the production of interferon gamma (IFN-gamma), tumour necrosis factor alpha (TNF) and interleukin 10 (IL-10) in peripheral blood lymphocytes by flowcytometry after stimulation without and with IgG in different doses ( 1, 5 and 10 mg/ml). Results - IFN-gamma and TNF were decreased significantly (P = 0.001) in the untreated and interferon beta (IFN-beta) treated patients after stimulation with IgG. In contrast, IL-10 production was significantly enhanced (P = 0.001) at least in the untreated patient group. The reduction of the pro-inflammatory cytokines IFN-gamma and TNF after stimulation with different IgG doses was clearly dose-dependent in all groups. Conclusion - Besides a suppression of the pro-inflammatory cytokines IFN-gamma and TNF, IgG enhances the anti-inflammatory cytokine IL-10. This effect is dose-dependent, speaking in favour of higher IgG doses in the treatment of MS.