title: Double seronegative myasthenia gravis with antiphospholipid syndrome: a case report.
abstract: BACKGROUND
  Myasthenia gravis is an autoimmune disease characterized by fluctuating muscle weakness. It is often associated with other autoimmune disorders, such as thyroid disease, rheumatoid arthritis, systemic lupus erythematosus, and antiphospholipid syndrome. Many aspects of autoimmune diseases are not completely understood, particularly when they occur in association, which suggests a common pathogenetic mechanism.
  
  
  METHODS
  We report a case of a 42-year-old Caucasian woman with antiphospholipid syndrome, in whom myasthenia gravis developed years later. She tested negative for both antibodies against the acetylcholine receptor and against muscle-specific receptor tyrosine-kinase, but had typical decremental responses at the repetitive nerve stimulation testing, so that a generalized myasthenia gravis was diagnosed. Her thromboplastin time and activated partial thromboplastin time were high, anticardiolipin and anti-β2 glycoprotein-I antibodies were slightly elevated, as a manifestation of the antiphospholipid syndrome. She had a good clinical response when treated with a combination of pyridostigmine, prednisone and azathioprine.
  
  
  CONCLUSIONS
  Many patients with myasthenia gravis test positive for a large variety of auto-antibodies, testifying of an immune dysregulation, and some display mild T-cell lymphopenia associated with hypergammaglobulinemia and B-cell hyper-reactivity. Both of these mechanisms could explain the occurrence of another autoimmune condition, such as antiphospholipid syndrome, but further studies are necessary to shed light on this matter.Clinicians should be aware that patients with an autoimmune diagnosis such as antiphospholipid syndrome who develop signs and neurological symptoms suggestive of myasthenia gravis are at risk and should prompt an emergent evaluation by a specialist.
authors.affiliation: Department of Rheumatology and Clinical Immunology, University Hospital Insel, 3010 Bern, Switzerland. diana.dan@insel.ch.
authors.forename: Diana
authors.initials: D
authors.lastname: Dan
authors.forename: Pierre-Alexandre
authors.initials: PA
authors.lastname: Bart
authors.forename: Jan
authors.initials: J
authors.lastname: Novy
authors.forename: Thierry
authors.initials: T
authors.lastname: Kuntzer
authors.forename: Carole
authors.initials: C
authors.lastname: Clair