Detection of antibodies to citric acid extract of skeletal muscle (CAE-ab) in the sera of patients with myasthenia gravis using indirect hemagglutination

In this paper are described the method and results for the demonstration of the antibodies to citric acid extract of skeletal muscle (CAE-ab) in the sera from myasthenia gravis (MG) patients with or without thymoma, in patients with other diseases and in healthy controls by an indirect hemagglutination assay (IHA), were described. The CAE-ab titers were positive in 15 (71.43%) of the 21 MG patients with thymoma, the antibody titers ranging from 1:16 to 1:512. In the 35 MG patients without thymoma, as well as in the 32 healthy controls and 22 patients with other diseases, the antibody titers were all negative A statistically significant difference was found between the CAE-ab titers in the group of MG patients with thymoma and those in the other three groups. It was considered that IHA for the purpose of demonstrating CAE-ab could serve as a supplementary diagnostic method for early detection of thymoma in MG patients at an early stage.