Clinical and immunological predictors of prognosis for Japanese patients with thymoma-associated myasthenia gravis

•Immunological markers for prognosis of thymoma-associated MG were investigated.•Anti-Kv1.4 positive patients frequently experienced thymoma recurrence and MG relapse.•Anti-Kv1.4 antibody was the only independent factor associated with MG relapse.•Anti-Kv1.4 antibody is a useful predictor of the prognosis of thymoma-associated MG.

There are no immunological markers to predict the prognosis of thymoma-associated myasthenia gravis (MG). Clinical and immunological factors associated with thymoma recurrence or MG relapse were examined by logistic analyses in 56 Japanese patients with thymoma-associated MG. Patients with anti-Kv1.4 antibodies showed higher frequencies of thymoma recurrence and MG relapse compared to those without. Anti-Kv1.4 antibody, Masaoka stage 4, World Health Organization type B3, and adjuvant radiotherapy were associated with thymoma recurrence. Multivariate analyses showed that anti-Kv1.4 antibody was the only independent factor associated with MG relapse. Anti-Kv1.4 antibody is a useful predictor of the prognosis of thymoma-associated MG.