title: Comparative clinical features and immune responses after extended thymectomy for myasthenia gravis in patients with atrophic versus hyperplastic thymus.
abstract: BACKGROUND
  Although extended thymectomy is believed to be suitable for myasthenia gravis (MG) patients with hyperplastic thymus, it is not clear whether surgical treatment is indicated for MG patients with atrophic thymus. We therefore assessed the clinical features and immune responses in 175 MG patients who underwent thymectomy between 1990 and 2004.
  
  
  METHODS
  All patients underwent extended thymectomy by the transsternal approach. Clinical features, prognosis, and immune response after extended thymectomy were compared in patients with atrophic and hyperplastic thymuses.
  
  
  RESULTS
  Of the 175 patients, 47 had atrophic and 128 had hyperplastic thymuses. Although the median times to complete stable remission of the two groups were similar (4.9 versus 4.8 years; p=0.513), the median time to clinical improvement was significantly longer in patients with atrophic thymus (3.3 versus 2.3 years; p=0.005). Patients with atrophic thymus showed a greater increase in ectopic thymus in the anterior mediastinal adipose tissue. Elevated B-cell activating factor receptor, CD19, and CD21 were observed in both hyperplastic and atrophic thymuses, although serum immunoglobulin G concentration after thymectomy increased more in patients with atrophic than in those with hyperplastic thymus.
  
  
  CONCLUSIONS
  Atrophic thymus may contribute to the progression of MG. Patients with MG who have a atrophic thymus show similar postoperative prognosis as those with hyperplastic thymus, suggesting that surgical therapy should also be considered for the former subset.
authors.affiliation: Department of Thoracic Surgery, the First Affiliated Hospital, and Department of Immunology, Sun Yat-sen University, Guangzhou, People's Republic of China. chenzhenguang@yahoo.com
authors.forename: Zhenguang
authors.initials: Z
authors.lastname: Chen
authors.forename: Honghe
authors.initials: H
authors.lastname: Luo
authors.forename: Yanwen
authors.initials: Y
authors.lastname: Peng
authors.forename: Lie
authors.initials: L
authors.lastname: Cai
authors.forename: Jinli
authors.initials: J
authors.lastname: Zhang
authors.forename: Chunhua
authors.initials: C
authors.lastname: Su
authors.forename: Jianyong
authors.initials: J
authors.lastname: Zou
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000097:blood; D001284:Atrophy / Q000276:immunology / Q000473:pathology / Q000601:surgery; D053264:B-Cell Activating Factor / Q000097:blood; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007132:Immunoglobulin Isotypes / Q000097:blood; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000276:immunology / Q000473:pathology / Q000601:surgery*; D012189:Retrospective Studies; D013934:Thymectomy; D013950:Thymus Gland / Q000473:pathology*; D013952:Thymus Hyperplasia / Q000276:immunology / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D015703:Antigens, CD; D053264:B-Cell Activating Factor; D007132:Immunoglobulin Isotypes