Plasmaperfusion on triptophan columns can improve the clinical outcome of patients affected with myasthenia gravis

Myasthenia Gravis (MG) is a neuromuscular disease often associated with thymic pathology due to neuromuscular transmission impairment by circulating antibodies directed against the cholinergic postsynaptic receptor on the neuromuscular junction (Anti-AchR-Ab). The treatment of MG includes cholinesterase inhibitors, steroids and thymectomy. Plasmapheresis can remove Anti-AchR-Ab but more recently plasma-perfusion (PP), a more specific apheresis for selective removal of noxious plasma components, has been developed. AIM OF THE STUDY: To study the effect of PP treatment, performed by using specific immunocolumns for Anti-AchR-Ab, on the clinical outcome of MG patients non-responder to steroid therapy or thymectomy. MATERIALS AND METHODS: We treated 8 patients suffering from severe MG by a cycle of 6 sessions of PP. We used columns containing triptophan as a specific ligand for Anti-AchR-Ab. In order to evaluate the effectiveness of treatment we used functional tests (muscular tests, respiratory function, electromyography) and laboratory tests (Anti-AchR-Ab; immunoglobulins, complement fractions, immunocomplexes). RESULTS: After one to three PP sessions, early clinical improvement in bulbar and respiratory symptoms were found in all patients and EMG showed improvement of neuromuscular transmission. Serum concentration of immunological markers decreased progressively and significantly during the treatment. Clinical improvements were progressive despite the tendency for Anti-AchR-Ab to reach initial values between one session and another. We observed no side effects due to the type of immunocolumns used. CONCLUSIONS: Triptophan columns appear to be able to remove large quantities of Anti-AchR-Ab and immunological markers from plasma. Our experience shows that PP performed using triptophan columns in patients suffering from severe MG provides good clinical results, improving patients' outcome, without any risk linked to the procedure.