Anti-skeletal muscle antibodies in the sera from myasthenic patients with thymoma: identification of anti-myosin, actomyosin, actin, and alpha-actinin antibodies by a solid-phase radioimmunoassay and a western blotting analysis.
We recently reported a strong association between the occurrence of anti-skeletal muscle (SM) antibodies and the presence of thymoma in patients with myasthenia gravis (MG). To further examine the immunoreactivity of MG sera against human muscle antigens, we developed a solid-phase radioimmunoassay (RIA) using purified muscle antigens and a Western blotting analysis in MG sera with high titers of anti-SM antibodies. Our results showed that MG patients with thymoma (thymoma group) had markedly high titers of anti-myosin and anti-actomyosin antibodies than those without thymoma (non-thymoma group). Furthermore, a close correlation was found between titers of anti-SM, anti-myosin and anti-actomyosin antibodies. The antibody titers against actin, alpha-actinin and tropomyosin were all low and did not correlate with titers of anti-SM antibodies. But, significant levels of these three antibodies were found in the thymoma group. By a Western blotting analysis, immunoreactivity of sera from the thymoma group appeared to be predominantly directed against myosin, actin and alpha-actinin.
Ohta
M
M
Department of Clinical Research Center, Utano National Hospital, Kyoto, Japan.
Ohta
K
K
Itoh
N
N
Kurobe
M
M
Hayashi
K
K
Nishitani
H
H
D001323:Autoantibodies / Q000032:analysis*; D015153:Blotting, Western; D006801:Humans; D009132:Muscles / Q000276:immunology*; D009157:Myasthenia Gravis / Q000097:blood / Q000150:complications / Q000276:immunology*; D011863:Radioimmunoassay; D011950:Receptors, Cholinergic / Q000276:immunology; D013945:Thymoma / Q000097:blood / Q000150:complications / Q000276:immunology*; D013953:Thymus Neoplasms / Q000097:blood / Q000150:complications / Q000276:immunology*
D001323:Autoantibodies; D011950:Receptors, Cholinergic