RESUMEN
Systemic lupus erythematosus and myasthenia gravis are autoimmune disorders in which genetic, environmental and hormonal as well as immunological factors have been implicated. We experienced a case of 24 year-old female patient developed SLE(anemia, leukopenia, facial malar rash, high titers of anti-DNA and anti-nuclear antibody) 3 years following successful therapeutic thymectomy for myas thenia gravis. A review of the world-wide literature revealed 8.3% to 24.3% association between myasthenia gravis and SLE. However there has been no controlled epidemiological study to prove a real association between these two disease. The differential diagnosis of fatigue and fever in patient with SLE should always include the possibility of myasthenia gravis.