Untreated hepatitis C may provoke myasthenia gravis

Recent reports have suggested a causative link between the use of interferon (INF[alpha]) treatment in chronic hepatitis C virus (HCV) infections and the development of myasthenia gravis. 1 2 This presents something of a conundrum given that low dose INF[alpha] has been advocated as a treatment for myasthenia and seems to be well tolerated in those with established disease. 3 Further confusion arises from the well established finding that untreated HCV infection itself leads to a markedly increased risk of developing various autoimmune conditions including rheumatoid arthritis, autoimmune thyroid disease, systemic lupus erythematosus, and polymyositis. 4 A recent retrospective study examined the prevalence of HCV markers in a population of 83 French myasthenic patients and found evidence for previous infection in 4.8%.