**2.3.1.5 Plasmapheresis and immunoglobulins**

Plasma exchange and intravenous immunoglobulin (IvIg) are used for short-term treatment of MG exacerbations and when it is desirable to achieve a rapid clinical response. Plasma exchange temporarily reduces the titer of circulating AChR- and MuSK-abs and usually produces immediate improvement (within days) in most MG patients (Newsom-Davis, Pinching et al. 1978). Circulating anti-AChR pathogenic factors can also be removed using immunoadsorption columns, some of which use immobilised AChR as an immunoadsorbent (Psaridi-Linardaki, Trakas et al. 2005). IvIg is widely used for patients with exacerbating MG. Support for its use comes from randomised controlled trials that show efficacy similar to plasma exchange (Gajdos, Chevret et al. 1997), equal efficacy of two doses (1 g/kg *vs* 2 g/kg) (Gajdos, Tranchant et al. 2005) and a recent double-blind, placebo controlled trial in patients with MG with worsening weakness (Zinman, Ng et al. 2007). The mechanisms by which intravenous immunoglobulins induce improvement are not clear, however studies in murine autoimmune models have implied that competition with autoantibodies and Fc-receptor binding are important factors in reducing the autoimmune response (Samuelsson, Towers et al. 2001).
