[Fundamental studies with respect to plasma exchange by using continuous-flow centrifuge system and the clinical trial in patients with myasthenia gravis].

A plasma exchange by using the continuous-flow centrifuge blood cell separator (IBM 2997) was carried out in 13 patients with various diseases including myasthenia gravis. The effects of the plasma exchange on blood components and side effects during the procedure were evaluated. In addition, 5 cases with severe myasthenia gravis who had failed to respond to medication were treated by plasma exchange, and the results were as follows: 1. Red blood cells, hemoglobin and hematocrit levels were significantly decreased while white blood cells inclined to increase after plasma exchange. In serum electrolytes and proteins there were no changes. 2. The side effects such as itching and eruption were observed in 46% of the patients. However, they disappeared within a short period. 3. In 2 cases with myasthenia gravis, a significant improvement in muscle weakness was observed by plasma exchange. In these cases, serum levels of the acetylcholine receptor antibody and the circulating immune complex were decreased, as compared with the previous levels. These parameters showed no correlation with severity of the disease.