Treatment of myasthenia gravis by immunoadsorption of plasma

We treated 16 patients with moderately severe to severe generalized myasthenia gravis (MG) by immunoadsorption (perfusion through a resin that adsorbs proteins) of 2,500 ml plasma on each of four alternate days. Fourteen patients who completed treatment all had significant improvement in strength (6 excellent, 6 good, and 2 fair), which began a mean of 42 hours after the first immunoadsorption, reached a maximum 4 days after the fourth immunoadsorption (mean, 250% of baseline strength), and returned to baseline over a mean of 2 months. Thirty-seven grams of plasma proteins were removed during each immunoadsorption, which required no replacement, compared with 175 grams during plasma exchange, which requires replacement with albumin. Serum or plasma concentration of all proteins fell, more so for most of the larger proteins than for the smaller ones: acetylcholine receptor antibody (AChR Ab) fell to a mean of 23% of original level, fibrinogen to 26%, C4 to 29%, IgM to 33%, IgG to 35%, CH50 to 41%, C3 to 42%, IgA to 54%, and albumin to 76%. All proteins, including AChR Ab, returned to their original levels within 1 to 3 weeks after the last immunoadsorption, while improvement in strength lasted a mean of 6 weeks longer. One seronegative patient had excellent improvement lasting more than a month. Activated complement C5a and white blood cell count rose during each immunoadsorption, while activated complement C3a fell, and each returned to its original level within hours. Eight patients had transient symptomatic hypotension attributable to withdrawal of blood more rapidly than it was returned; this hypotension was prevented or ameliorated by intravenous saline.(ABSTRACT TRUNCATED AT 250 WORDS)