Cytokine levels in various intravenous immunoglobulin (IVIg) preparations

The mechanisms of action of intravenous immunoglobulin (IVIg) in autoimmune diseases include modulation of cytokine levels. We examined therefore whether direct infusion of abnormally high levels of 13 different cytokines or cytokine-inhibitors within 5 different IVIg preparations have any role in modulation of their levels. None of the measured cytokines in any of the IVIg preparations tested were above the normal levels, and regarding some no traces could be detected. Hence, modulation of cytokine levels following IVIg therapy involves other mechanisms such as interference with their secretion or cytokine-specific blocking antibodies, rather than direct infusion of cytokines.