The effectiveness of thymectomy on seronegative generalized myasthenia gravis: comparing with seropositive cases
Authors: Yuan, H. K.1; Huang, B-S.2; Kung, S-Y.3; Kao, K-P.1
Source: Acta Neurologica Scandinavica, Volume 115, Number 3, March 2007 , pp. 181-184(4)
Publisher: Blackwell Publishing
Abstract:
Yuan HK, Huang B-S, Kung S-Y, Kao K-P. The effectiveness of thymectomy on seronegative generalized myasthenia gravis: comparing with seropositive cases.Acta Neurol Scand 2007: 115: 181-184. © Blackwell Munksgaard 2006. Objectives - To investigate the efficacy of thymectomy between patients with seronegative myasthenia gravis (SNMG) and seropositive myasthenia gravis (SPMG). Methods - We present here the first Taiwanese retrospective paired cohort study comparing the effectiveness of thymectomy among 16 seronegative and 32 seropositive MG patients after matching for age-of-onset and time-to-thymectomy, and following up over a mean of 35 ± 20 (7-86) months. Clinical characteristics and complete stable remission (CSR) rates were compared and analyzed between the groups. Results - There were no major clinical differences between the two groups except for our finding of a lower percentage of SNMG receiving preoperative plasmapheresis or human immunoglobulin than SPMG (31% for SNMG vs 72% for SPMG, P = 0.007). CSR rates calculated using the Kaplan-Meier method were similar in the two groups (38% for SNMG vs 50% for SPMG, P = 0.709). The median time for CSR was 47.4 months for SNMG and 48.2 months for SPMG. Thymic hyperplasia were the most common pathology (69% for SNMG vs 88% for SPMG, P = 0.24). During the follow-up period, we found no group difference on prednisolone or pyridostigmine dosages. Significant postoperative dosage reductions on pyridostigmine, but not on prednisolone, were found in both groups. Conclusions - Thymectomy has a comparable response among SNMG and SPMG in our study. Thymic hyperplasia is prevalent in our SNMG patients and thymectomy may also be a therapeutic option to increase the probability of remission or improvement in SNMG. More prospective controlled trial will be helpful in the future.Keywords: acetylcholine receptor antibody; AChRAb; immunosuppression; myasthenia gravis; non-thymomatous; seronegative; thymectomy
Document Type: Research article
DOI: 10.1111/j.1600-0404.2006.00733.x
Affiliations: 1: Neurological Institute 2: Thoracic Surgery Division 3: Pathology & Laboratory Medicine Department, Taipei Veterans General Hospital, National Yang-Ming University School of Medicine, Taipei, Taiwan

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