In patients treated with the monoclonal antibody infliximab (Remicade®) -which binds to and blocks tumor necrosis factor alpha (TNF-alpha) - an infusomat filter is routinely used to prevent the very same early adverse events observed in individuals receiving intravenous immunoglobulins (IVIG). We recently used such a filter in a patient suffering from malaise and vomiting in the context of an IVIG substitution therapy. In this patient symptoms improved and IVIG-induced complement-activation was reduced (unpublished observation).||Based on this simple observation we hypothesize that this simple and approved filter-system may be efficient in retaining complement-activating immunoglobulin G (IgG) aggregates in IVIG-preparations. This effect may reduce complement activation - and consecutive inflammation - thereby diminishing adverse events.||In this prospective study we propose to investigate how complement activation and side effects after IVIG infusion relate in individuals receiving conventional (i.e. unfiltered) vs. filtered IVIG-preparations.