AB007. The impact of immunological indicators on the prognosis of thymectomy in patients with thymoma-associated myasthenia gravis

Background: Extensive research has illuminated the complex landscape of immunological disparities in patients suffering from thymoma-associated myasthenia gravis (MG), a condition marked by considerable fluctuations in immune system markers. The intricate relationship between these immunological aberrations and the therapeutic efficacy of thymectomy remains an area ripe for investigation, underscoring the necessity of this study to unravel the potential impact of specific immunological markers on the postoperative prognosis of MG in individuals afflicted with thymoma. This study aims to identify preoperative immunological markers—including T-cell subsets, immunoglobulins, and complement components—predictive of long-term outcomes in thymoma-associated MG patients undergoing thymectomy.

Methods: We embarked on a comprehensive retrospective analysis encompassing a cohort of 163 patients diagnosed with MG, all of whom underwent thymectomy at our institution within the period from January 2011 to December 2022. The methodological core of our investigation centered around the deployment of Kaplan-Meier survival analysis coupled with Cox proportional hazards modeling. This dual analytical framework enabled us to dissect the nuanced relationship between a predefined set of immunological markers—namely, TH17 cells, Treg cells, CD4⁺ T cells, CD8⁺ T cells, and a range of immunoglobulins [immunoglobulin G (IgG), immunoglobulin A (IgA), immunoglobulin M (IgM), and immunoglobulin E (IgE)], along with C-reactive protein (CRP), complement C3, and complement C4—and the subsequent prognostic landscape post-thymectomy.

Results: Among the patients participating in this study, 88 achieved sustained relief after surgery, while 68 patients experienced unchanged, recurrent, or aggravated symptoms of MG after surgery, including a history of recurrence; Another 7 patients died due to MG, with an average follow-up period of 68.2 months. Through univariate and multivariate regression analysis, we found a significant correlation (P<0.001) between the decrease in complement C3 levels and the inability of patients to achieve sustained relief of MG symptoms after surgery. And the level of T cells in the body immunological indicators such as IgG are not associated with prognosis.

Conclusions: The study conclusively underscores the prognostic valor of complement C3 levels in shaping the long-term therapeutic trajectory of patients with thymoma-associated MG undergoing thymectomy. Lower C3 levels as a predictive marker for a heightened risk of postoperative MG symptom exacerbation heralds the potential of complement C3 as an instrumental prognostic tool.

Keywords: Immunological indicators; thymoma; myasthenia gravis (MG)