ABSTRACT
BACKGROUND: Intravenous immunoglobulin (IVIg) has been widely used in the management of patients with various autoimmune neurological diseases, however, its action mechanisms have not fully been elucidated yet. This study focused on the effects of IVIg on the production of interleukin-6 (IL-6), one of major proinflammatory cytokine, using a human skeletal muscle cell line (HM4). METHODS: After HM4 cells were cultured in Dulbecco's modified eagle's medium (DMEM) containing 5% fetal bovine serum for 24 h, the culture medium was changed with serum-free media. TNF-alpha (tumor necrosis factor-alpha, 100 ng/mL) and IVIg (5 mg/mL) were treated alone or in combination and cultured for various time. RT-PCR and ELISA kit were employed for mRNA expression and secretion of IL-6, respectively. RESULTS: Treatment with TNF-alpha or/and IVIg significantly induced IL-6 mRNA expression (p<0.001). Although IL-6 production was markedly increased by TNF-alpha (p<0.001), IVIg treatment alone or in combination with TNF-alpha had no effect on the production of IL-6 except at 6 h after the treatment. CONCLUSIONS: IVIg seems not to have a significant effect on IL-6 production as an action mechanism of its immunomodulatory capabilities, at least in the HM4 cell line.