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-γ), 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-γ and TNF were decreased significantly (P = 0.001) in the untreated and interferon beta (IFN-β) 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-γ 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-γ 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.