A comparison of long-term post-thymectomy outcome of anti-AChR-positive, anti-AChR-negative and anti-MuSK-positive patients with non-thymomatous myasthenia gravis.

Objective: A single-centre, non-randomized, non-controlled study was designed to compare the long-term post-thymectomy clinical outcome in anti-AChR-positive, anti-AChR-negative and anti-MuSK-positive patients with non-thymomatous myasthenia gravis (MG). Methods: A total of 331 consecutive patients with seropositive MG, 55 with seronegative MG and 10 with anti-MuSK-positive MG underwent extended transsternal thymectomy (T-3b according to Myasthenia Gravis Foundation of America). The primary endpoint was to assess differences in the rate of complete stable remission (CSR) in patients with and without anti-AChR and anti-MuSK antibodies. Results: The mean follow-up was 218.3 (SD 128.1) months in the seropositive MG group, 149.8 (SD 131.1) in the seronegative group and 169.9 (SD 116) in the anti-MuSK-positive group. In the seropositive MG group, the probability of obtaining CSR at 5 years post-thymectomy was 51.1% for the seropositive group compared with 40 for the seronegative group (p = 0.05) and 20 for the...