Thymus involvement in myasthenia gravis: Epidemiological and clinical impacts of different self-tolerance breakdown mechanisms.
The reasons for the abrogation of self-immunological tolerance in patients with myasthenia gravis (MG) may be different between those with concomitant thymic hyperplasia or thymoma, and those with no evidence of thymic involvement. We conducted a retrospective observational case series study to investigate the epidemiology as well as the clinical, serologic, and electromyographic (EMG) characteristics of individuals diagnosed as having MG. We found that the average age at MG onset of patients with either thymic hyperplasia or thymoma was much younger (by ~20years) than that of MG patients without thymic involvement. Thymic hyperplasia was more common in females than males. There were no differences in the rates of ocular MG vs. generalized MG among those three study groups. There were also no group differences in the rates of neuromuscular junction disfunction, as observed on EMG or by the results of serology tests for acetyl choline receptor antibody. Interestingly, only patients without thymic involvement had other autoimmune diseases, and most of them were females. The patients with other coexisting autoimmune disease had a similar age at MG onset as the other patients with no thymic involvement. These results shed light on the impact of epidemiological and clinical factors that result from different mechanisms of self-immunological tolerance breakdown that occurs in MG.
['Karni|Arnon|A|', 'Asmail|Ali|A|', 'Drory|Vivian E|VE|', 'Kolb|Hadar|H|', 'Kesler|Anat|A|']
D000328:Adult D017668:Age of Onset D000368:Aged D001323:Autoantibodies D004576:Electromyography D005260:Female D006801:Humans D008297:Male D008875:Middle Aged D009157:Myasthenia Gravis D011950:Receptors, Cholinergic D012189:Retrospective Studies D017634:Self Tolerance D012737:Sex Factors D013945:Thymoma D013950:Thymus Gland D013952:Thymus Hyperplasia
Myasthenia gravis Thymic hyperplasia Thymoma