Anti-AChR-negative myasthenia gravis: clinical and immunological features.

The clinical and immunological characteristics of myasthenia gravis (MG) patients without detectable anti-Acetylcholine Receptor (anti-AChR) antibody were studied. Sixty anti-AChR negative MG patients were compared with 287 anti-AChR positive cases. Significant differences were found with respect to the sex incidence, the disease severity and the thymic pathology, while the age at the onset of the disease, the presence of other auto-antibodies and the efficacy of medical treatments were similar in the two groups of patients. Anti-AChR-negative MG could have pathogenetic mechanisms different from the antibody-positive disease.