Metastatic Thymoma-Associated Myasthenia Gravis: Favorable Response to Steroid Pulse Therapy Plus Immunosuppressive Agent

Thymoma with pleural metastases

Metastatic thymoma is a rare and serious condition that is treated with cytostatics according to the guidelines. Cytostatics have limited efficacy and are toxic. This case report illustrates how glucocorticoid treatment can have a significant effect.

MiR-522-3p inhibits proliferation and activation by regulating the expression of SLC31A1 in T cells

We investigated the role of miR-522-3p in thymoma-associated myasthenia gravis (TAMG), and the mechanism of action in T cells. The miR-522-3p expression in normal serum, non-thymoma MG patient serum and TAMG patient serum and tissues was detected by quantitative real-time PCR (qRT-PCR), respectively. We assessed miR-522-3p expression in Jurkat cells and human CD4+ T cells after activation by anti-CD3 and anti-CD28 using qRT-PCR. The viability, proliferation, cycle distribution and the levels of CD25, CD69, interleukin-2 (IL-2) and IL-10 in transfected Jurkat cells were detected by Cell counting kit-8, 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, qRT-PCR, respectively. Targeting relationships of miR-522-3p and SLC31A1 were predicted and validated by bioinformatics analysis and dual-luciferase reporter. The viability, proliferation, cycle distribution and the levels of SLC31A1, CD25, CD69, IL-2 and IL-10 in transfected Jurkat cells were detected by above methods and western blot. The miR-522-3p expression was declined in TAMG and activated T cells. MiR-522-3p inhibitor promoted cell viability, EdU positive cells, cycle progression, and the level of CD25, CD69, IL-2 and IL-10 in Jurkat cells, while the effect of miR-522-3p mimic was the opposite. SLC31A1 was targeted by miR-522-3p, and miR-522-3p inhibited SLC31A1 expression. Overexpressed SLC31A1 reversed the inhibitory effects of miR-522-3p mimic on cell viability, EdU positive cell, cycle progression, and the levels of IL-2 and IL-10 in transfected Jurkat cells. MiR-522-3p expression was down-regulated in TAMG, and miR-522-3p inhibited proliferation and activation by regulating SLC31A1 expression in T cells.

Thymoma-associated myasthenia gravis: Clinical features and predictive value of antiacetylcholine receptor antibodies in the risk of recurrence of thymoma

Background

Thymoma‐associated myasthenia gravis (TAMG) is one of the subtypes of myasthenia gravis with autoantibodies against the acetylcholine receptor (AChR‐Ab). We analyzed the clinical features of our cohort of TAMG patients and the changes in AChR‐Ab titer before and after thymectomy in order to identify factors predicting thymoma relapses.

Methods

We retrospectively assessed: age of MG onset, MG clinical status according to MGFA (Myasthenia Gravis Foundation of America), epoch of thymectomy, post‐thymectomy status, oncological features and surgical approach. AChR‐Ab dosages were measured both before and after thymectomy. Linear regression models were applied to identify clinical determinants of AChR‐Ab titers and the Cox regression model was fitted to estimate the factors associated with the risk of thymoma recurrence.

Results

The study sample included 239 MG patients, 27 of whom experienced one or more recurrences (median follow‐up time: 4.8 years). The AChR‐Ab titers decreased after first thymectomy (P < 0.001); the decrease was more pronounced in female patients (P = 0.05), in patients diagnosed with MG at an older age (P = 0.003), and in those who had lower MG stage before surgery (P = 0.02) or higher Masaoka‐Koga stage (P = 0.005). The risk of relapse was closely linked with the age of the patient, the Masaoka‐Koga stage and the surgical approach.

Conclusions

Presurgery levels of AChR‐Ab or their change after surgery were not associated with thymoma recurrence. The reduction of AChR‐Ab titers after thymectomy confirms an immunological role of thymoma in the pathogenesis of MG.

Key points

Significant findings of the study: Young MG patients with an advanced Masaoka staging score of the primary tumor who underwent thymectomy with approaches different from sternotomy and VATS should be monitored for high risk of recurrence.

What this study adds: No other study has ever investigated the changes in AChR‐Ab titers before and after thymectomy in a large cohort of TAMG patients. The reduction of AChR‐Ab titers after thymectomy suggests an immunological role of thymoma in the pathogenesis of MG.

Docetaxel/cisplatin Therapy in Myasthenia Gravis with Hypertension/diabetes

Background

Therapeutic options for thymoma-associated myasthenia gravis (MG) patients complicated with hypertension and/or diabetes post thymectomy are often conventional steroids. As the prevalence of diabetes and hypertension globally increases, other therapeutic options for these patients are of great importance.

Material/methods

9 patients with thymoma-associated MG complicated with hypertension and/or diabetes after thymectomy were administered 75 mg/m2 of docetaxel and 70 mg/m2 of cisplatin on day 1. The treatment could be repeated at 3-week intervals, ranging from 1 to 4 cycles according to the status of the patients. Therapeutic efficacy and side effects were evaluated.

Results

2 patients were complicated with type 2 diabetes, 6 with hypertension, and 1 with both diabetes and hypertension. After docetaxel/cisplain therapy, the MG symptoms were markedly improved in all patients (2, complete remission; 3, basic remission; 3, marked improvement; 1, improvement). Acetylcholine receptor (AchR) antibody levels were decreased in 8 patients. Minor adverse effects were observed in 2 patients, 1 with Grade II gastrointestinal reaction, and the other with pulmonary infection.

Conclusion

Docetaxel plus cisplatin might be an effective therapeutic option for thymoma-associated MG patients complicated with hypertension /diabetes post thymectomy without worsening thymoma and hypertension / diabetes.