Clinical trial of plasma exchange and high-dose intravenous immunoglobulin in myasthenia gravis

We have conducted a trial to randomly assess the efficacy and tolerance of intravenous immunoglobulin (IVIg) or plasma exchange (PE) in myasthenia gravis (IVIG) exacerbation and to compare two doses of IVIg. Eighty-seven patients with IVIG exacerbation were randomized to receive either three PE (n = 41), or IVIg (n = 46) 0.4 gm/kg daily further allocated to 3 (n = 23) or 5 days (n = 23). The main end point was the variation of a myasthenic muscular score (MSS) between randomization and day 15. The MSS variation was similar in both groups (median value, +18 in the PE group and +15.5 in the IVIg group; p = 0.65). Similar efficacy, although slightly reduced in the 5-day group was observed with both IVIg schedules. The tolerance of IVIg was better than that of PE with a total of 14 side effects observed in 9 patients, 8 in the PE group and 1 in the IVIg group (p = 0.01). Although our trial failed to show a pronounced difference in the efficacy of both treatments, it exhibited a very limited risk for IVIg IVIg is an alternative for the treatment of myasthenic crisis. The small sample sizes in our trial, however, could explain why a difference in efficacy was not observed. Further studies are needed to compare PE with IVIg and to determine the optimal dosage of IVIg.