Determination of acetylcholine receptor antibody in myasthenia gravis: clinical usefulness and pathogenetic implications.

Antibodies to cholinergic receptor structures were found in 75% of 76 Finnish and 93% of 175 Swedish patients with myasthenia gravis. The amount of antibodies showed a positive correlation to the severity of the disease, and was reduced during immunosuppressive treatment, and by thymectomy. Thymoma patients had high values. The antibody was also found in the cerebrospinal fluid. Two healthy newborn babies of myasthenic mothers had antibodies during the first weeks of life, in spite of no clinical symptoms. The occurrence of IgM antibodies before IgM antibodies in two patients during the early stages of myasthenia gravis suggests that the antibody is not a primary cause of the disease.