Delving into immune modulation: thymectomy in myasthenia gravis

Abstract

Objective: The study aims to investigate the impact of thymectomy (TX) on immune function and cytokines levels in patients with myasthenia gravis (MG). Methods: A total of 44 patients with MG were enrolled in the study, divided into two groups based on the treatment they received: the MG-TX group (14 MG patients who underwent thymectomy) and the control group (30 MG patients who received drug treatment alone). Patients were assessed at baseline (0 months), 1 month, 3 months, 6 months, and 12 months post-treatment. The levels of T lymphocytes subtypes (CD3+, CD4+, CD8 + T cells, and the CD4+/CD8 + ratio), immunoglobulins and complements levels (IgG, IgM, IgA, C3 and C4), and cytokines (IL-2, IL-4, IL-6, INF-γ, and TNF-α) were measured and compared between the two groups. Results: At baseline, both the MG-TX and control groups exhibited similar levels of immune markers. Following thymectomy, there was a significant decrease in CD3+, CD4+, and CD8 + T cell levels at 1 month, which remained stable throughout the study period. At 12 months, the CD4 + levels in the MG-TX group were significantly lower than in the control group (P < 0.001). Additionally, the CD4/CD8 ratio was significantly lower in the MG-TX group at both 6 months and 12 months (P < 0.01 and P < 0.001, respectively). No significant changes in immunoglobulin and complement levels were observed in either group throughout the study. For cytokines, IL-2, IL-6, INF-γ, and TNF-α levels decreased significantly at 1-month post-treatment (P < 0.001). At 3 months, INF-γ levels in the MG-TX group remained higher than in the control group (P < 0.001), but stabilized by 6 months and 12 months. IL-4 levels significantly increased at 1 month post-treatment (P < 0.001), but at 12 months, the control group had higher IL-4 levels than the MG-TX group (P < 0.05). Conclusion: Thymectomy in MG patients results in a long-term decrease in T lymphocyte levels and a shift in the CD4/CD8 ratio. The procedure also induces transient changes in cytokine levels, which stabilize after 3 months. These findings suggest that thymectomy has a lasting impact on cellular immunity and cytokine secretion, with potential implications for immune system function and the risk of infections in MG patients.