[Long-term treatment of refractory myasthenia gravis with immunoadsorption]

Myasthenia gravis in the majority of patients is a well treatable neurological autoimmune disorder with a prevalence of 60-150 per million. For the treatment of myasthenic crisis in the intensive care unit the use of therapeutic apheresis, e. g. immunoadsorption or plasma exchange, is well established due to its rapid therapeutic effect, whereas the necessity in long term treatment is still questioned. Aim of this retrospective cohort-study was the assessment of patients with refractory myasthenia gravis in Germany treated by regular immunoadsorption, the characterization of previous therapies and the efficacy of long-term treatment.

In total 14 patients (9 women, 5 men, mean age: 40.5 years) were identified in Germany using regular therapeutic apheresis. 13 were treated with different modes of immunoadsorption (10 yen l-tryptophan-adsorption, 2 yen epitope-specific adsorption, 1 yen polyclonal sheep antibody on sepharose) and 1 with plasma exchange. Mean duration of standard treatment of myasthenia gravis before initiation of regular apheresis was 7.8 years.

Average duration of analyzed apheresis treatment was 6.4 years, with a mean treatment-interval of 1.1 per week. Mean reduction rate of autoantibodies against acetylcholine-receptor-protein was 50-60 % per session. After initiation of immunoadsorption the mean time of hospitalisation decreased significantly by app. 60 %. In particular the number of myasthenic crises could be reduced by 89 % per year. Tolerability of immunoadsorption was very good, no severe adverse events occurred.

In conclusion, for the treatment of the subgroup of myasthenia gravis patients becoming refractory to standard treatment immunoadsorption should be regarded as integral part of the therapeutic armamentarium to stabilize and optimize the state of neurologic rehabilitation. This evaluation should be also carefully considered by carriers of health care cost as currently best available evidence to decide on appropriate treatment regimens for these rare patients.