Anti-acetylcholine receptor antibody titer with extended thymectomy in myasthenia gravis.

Twenty-four patients with myasthenia gravis of Osserman's generalized type underwent extended thymectomy through a sternal-splitting approach. Their clinical responses to thymectomy and postoperative changes in anti-acetylcholine receptor antibody titers were evaluated. The follow-up time ranged from 1 month to 7 years and 7 months (average, 36 months). Six patients (25%) had remissions and 17 patients (71%) were improved after operation. The preoperative anti-acetylcholine receptor antibody titers dropped significantly after operation (p less than 0.001). The postoperative reduction in these titers correlated with the time course after operation (p less than 0.05). Their postoperative reduction was significantly greater in the six patients having remissions than in the 15 having marked (p less than 0.02) and the six having moderate improvement (p less than 0.005). This study has revealed that anti-acetylcholine receptor antibody titer in plasma declines progressively after thymectomy, and the postoperative reduction of this titer correlates with the clinical effect of thymectomy.