title: Myasthenia gravis: mitotic activity of thymus-dependent and blood-lymphocytes.
abstract: The thymus and blood lymphocytes of 20 thymectomized patients with myasthenia gravis, including 3 cases of thymoma, have been studied for mitotic activity (spontaneous mitotic activity of native thymocytes, responsiveness of cultured cells to PHA, DNA-polymerase specific activity). The myasthenic thymus gland was found to be the site of a spontaneous DNA-synthesis of similar intensity as the mitotic activity of the thymus in infancy. This was also reflected by the DNA-polymerase activity of the cells. While the thymocyte cultures responded well to PHA stimulation in 50% of the cases, the blood-lymphocytes were found unresponsive. There was a partial correlation between the individual parameters of mitotic activity, but practically none between the mitotic activity and the clinical severity of myasthenia or the histological features of the thymus or of thymoma. Except in the latter cases, a correlation was found between mitotic activity and preoperative immunosuppressive treatment. It is suggested that the T-lymphocytes are not directly involved in the pathomechanism of myasthenia gravis.
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D004247:DNA / Q000096:biosynthesis; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D005260:Female; D006801:Humans; D007165:Immunosuppression Therapy; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D008938:Mitosis; D009157:Myasthenia Gravis / Q000276:immunology*; D009362:Neoplasm Metastasis; D011879:Radiotherapy Dosage; D013601:T-Lymphocytes / Q000276:immunology; D013934:Thymectomy; D013945:Thymoma / Q000276:immunology; D013952:Thymus Hyperplasia / Q000276:immunology; D013953:Thymus Neoplasms / Q000276:immunology
chemical_list: D004247:DNA; D004259:DNA-Directed DNA Polymerase