Oligoclonal peripheral T-cell lymphocytosis as a result of aberrant T-cell development in a cortical thymoma

Prognostic value of systemic inflammatory markers and the nutrition status in thymic epithelial tumors with complete resection

Background

Recent studies have shown that several systemic inflammatory markers and the nutrition status, including the neutrophil‐to‐lymphocyte ratio (NLR), monocyte‐to‐lymphocyte ratio (MLR), platelet‐to‐lymphocyte ratio (PLR), and prognostic nutritional index (PNI), are useful prognostic factors in several malignant tumors. The present study explored the prognostic value of the NLR, MLR, PLR, and PNI in thymic epithelial tumor (TET) patients who underwent complete resection.

Methods

A total of 158 TET patients who underwent complete resection were involved in the analysis. Their NLR, MLR, PLR, and PNI values were obtained from a blood examination within one month before the initiation of treatment. A receiver operating characteristic curve analysis was conducted to determine the optimal cutoff values.

Results

The enrolled patients were stratified by cutoffs of 4.35 for the NLR, 0.22 for the MLR, 130.18 for the PLR, and 44.02 for the PNI. A univariate analysis revealed that high‐grade malignant TET, including type B2 and B3 thymoma, thymic carcinoma, and thymic neuroendocrine tumor; an advanced Masaoka stage; a high NLR; a high MLR; and a low PNI were significant predictors of a poor disease‐free survival (DFS). A multivariate analysis confirmed that an advanced Masaoka stage (HR = 5.5557, p = 0.0007) and a high MLR (HR = 3.3371, p = 0.0264) were independent predictors of a poor DFS.

Conclusions

Our study demonstrated that the pretreatment MLR was an independent predictor of the DFS in patients with TETs who underwent complete resection.

Peripheral blood T lymphocytosis in thymoma: an insight into immunobiology

PURPOSE

Peripheral blood T lymphocytosis (PBTL) is a rare, yet poorly understood manifestations of thymoma, which is postulated to be linked with autoimmune/paraneoplastic manifestations such as myasthenia gravis (MG), pure red cell aplasia (PRCA), etc.; more commonly encountered in this neoplasm.

METHOD

We aim to describe the flowcytometric immunophenotypic data of PBTL in a 43-year-old male; 6 months after successful completion of chemoradiotherapy (CT/RT) for a large, invasive, and metastatic type B1 thymoma; and present a comprehensive review of all such cases reported over last 42 years (N = 21) (1977-2019).

RESULT

A larger size of the tumors (≥ 10 cm), presence of local invasion and/or distant metastasis, and type B (cortical or lymphocyte rich) histology were more likely to be associated with PBTL. Tumors associated with MG/PRCA (N = 9/21) tend to have lower PBTL compared to those without such manifestations; and PBTL subsided following thymectomy with or without CT/RT. Immunophenotypic analysis of PB revealed a CD8 +  > CD4 + mature (naïve) polyclonal T cells resembling late cortical thymocytes.

CONCLUSION

Thymic intratumoral microenvironment might influence occurrence PBTL that may have a pathophysiologic link to development of autoimmune manifestations. Immunophenotypic characteristics of peripheral blood lymphoid cells should be the clue for accurate characterization and to avoid a misdiagnosis of a lymphoproliferative neoplasm.

Assessment of the prognostic role of neutrophil-to-lymphocyte ratio following complete resection of thymoma

BACKGROUND

The introduction of the new TNM staging system for thymic epithelial malignancies produced a significant increase in the proportion of patients with stage I disease. The identification of new prognostic factors could help to select patients for adjuvant therapies based on their risk of recurrence. Neutrophil-to-lymphocyte ratio (NLR) has recently gained popularity as reliable prognostic biomarker in many different solid tumors. The aim of this study is to assess the utility of NLR evaluation as a prognostic marker in patients with surgically-treated thymoma.

METHODS

A retrospective analysis was conducted among patients who underwent resection for thymoma in a single center. Patients were divided in two groups, under (low-NLR-Group = 47 patients, 60%) and above (high-NLR-Group = 32 patients, 40%) a ROC-derived NLR cut-off (2.27). Associations with clinical-pathological variables were analyzed; disease-free survival (DFS) was identified as the primary endpoint.

RESULTS

Between 2007 and 2017, 79 patients had surgery for thymoma. Overall 5-year DFS was 80%. Univariate survival analysis demonstrated that NLR was significantly related to DFS when patients were stratified for TNM stage (p = 0.043). Five-year DFS in the low-NLR-Group and in the high-NLR-Group were respectively 100 and 84% in stage I-II, and 66 and 0% in stage III. TNM stage resulted as the only independent prognostic factor at multivariate analysis, with hazard ratio of 3.986 (95% CI 1.644-9.665, p = 0.002).

CONCLUSIONS

High preoperative NLR seems to be associated to a shorter DFS in patients submitted to surgery for thymoma and stratified for TNM stage.

Thymoma-associated lymphocytosis in a dog

A 9-year-old female spayed English Springer Spaniel was evaluated for a cranial mediastinal mass and lymphocytosis. Flow cytometric immunophenotyping of peripheral blood lymphocytes revealed 97% as CD3 positive, confirming a T-cell lineage. Additionally, T-cell subset assessment showed 53.2% to be double-negative T-lymphocytes, expressing neither CD4 nor CD8 surface markers. The number of double-negative lymphocytes in circulation coincided with the number of T-cell receptor (TCR) γδ-expressing T-cells in circulation. Molecular T-cell clonality analysis of TCR Gamma (TCRG) gene rearrangement showed a polyclonal expansion of T-lymphocytes. Histopathology confirmed the mass to be a thymoma, supporting the diagnosis of thymoma-associated T-cell lymphocytosis. Resolution of the lymphocytosis after removal of the thymoma provided further evidence for this diagnosis. To the authors' knowledge, this case is only the second report of thymoma-associated peripheral lymphocytosis in the veterinary literature, and is the first to report a confirmed thymoma-associated peripheral γδ T-cell lymphocytosis in a dog.

Phase II study of belinostat in patients with recurrent or refractory advanced thymic epithelial tumors

PURPOSE

Thymic epithelial tumors are rare malignancies, and there is no standard treatment for patients with advanced disease in whom chemotherapy has failed. Antitumor activity of histone deacetylase (HDAC) inhibitors in this disease has been documented, including one patient with thymoma treated with the pan-HDAC inhibitor belinostat.

PATIENTS AND METHODS

Patients with advanced thymic epithelial malignancies in whom at least one line of platinum-containing chemotherapy had failed were eligible for this study. Other eligibility criteria included adequate organ function and good performance status. Belinostat was administered intravenously at 1 g/m(2) on days 1 to 5 of a 21-day cycle until disease progression or development of intolerance. The primary objective was response rate in patients with thymoma.

RESULTS

Of the 41 patients enrolled, 25 had thymoma, and 16 had thymic carcinoma; patients had a median of two previous systemic regimens (range, one to 10 regimens). Treatment was well tolerated, with nausea, vomiting, and fatigue being the most frequent adverse effects. Two patients achieved partial response (both had thymoma; response rate, 8%; 95% CI, 2.2% to 25%), 25 had stable disease, and 13 had progressive disease; there were no responses among patients with thymic carcinoma. Median times to progression and survival were 5.8 and 19.1 months, respectively. Survival of patients with thymoma was significantly longer than that of patients with thymic carcinoma (median not reached v 12.4 months; P = .001). Protein acetylation, regulatory T-cell numbers, and circulating angiogenic factors did not predict outcome.

CONCLUSION

Belinostat has modest antitumor activity in this group of heavily pretreated thymic malignancies. However, the duration of response and disease stabilization is intriguing, and additional testing of belinostat in this disease is warranted.

Thymomas alter the T-cell subset composition in the blood: a potential mechanism for thymoma-associated autoimmune disease

Thymomas are the only tumors that are proven to generate mature T cells from immature precursors. It is unknown, however, whether intratumorous thymopoiesis has an impact on the peripheral T-cell pool and might thus be related to the high frequency of thymoma-associated myasthenia gravis. This study shows, using fluorescence-activated cell sorting-based analyses and T-cell proliferation assays, that thymopoiesis and T-cell function in thymomas correspond with immunologic alterations in the blood. Specifically, the proportion of circulating CD45RA+CD8+ T cells is significantly increased in patients with thymoma compared with normal controls, in accordance with intratumorous T-cell development that is abnormally skewed toward the CD8+ phenotype. Moreover, it is primarily the proportion of circulating CD45RA+CD8+ T cells that decreases after thymectomy. The results also demonstrate that T cells reactive toward recombinant autoantigens are distributed equally between thymomas and blood, whereas T-cell responses to foreign antigen (ie, tetanus toxoid) are seen only among circulating T cells and not among thymoma-derived T cells. These functional studies support the hypothesis that thymopoiesis occurring within thymomas alters the peripheral T-cell repertoire. Because many thymomas are enriched with autoantigen-specific T cells, a disturbance of circulating T-cell subset composition by export of intratumorous T cells may contribute to paraneoplastic autoimmune disease arising in patients with thymoma.

Thymomas alter the T-cell subset composition in the blood: a potential mechanism for thymoma-associated autoimmune disease

Thymomas are the only tumors that are proven to generate mature T cells from immature precursors. It is unknown, however, whether intratumorous thymopoiesis has an impact on the peripheral T-cell pool and might thus be related to the high frequency of thymoma-associated myasthenia gravis. This study shows, using fluorescence-activated cell sorting-based analyses and T-cell proliferation assays, that thymopoiesis and T-cell function in thymomas correspond with immunologic alterations in the blood. Specifically, the proportion of circulating CD45RA+CD8+ T cells is significantly increased in patients with thymoma compared with normal controls, in accordance with intratumorous T-cell development that is abnormally skewed toward the CD8+ phenotype. Moreover, it is primarily the proportion of circulating CD45RA+CD8+ T cells that decreases after thymectomy. The results also demonstrate that T cells reactive toward recombinant autoantigens are distributed equally between thymomas and blood, whereas T-cell responses to foreign antigen (ie, tetanus toxoid) are seen only among circulating T cells and not among thymoma-derived T cells. These functional studies support the hypothesis that thymopoiesis occurring within thymomas alters the peripheral T-cell repertoire. Because many thymomas are enriched with autoantigen-specific T cells, a disturbance of circulating T-cell subset composition by export of intratumorous T cells may contribute to paraneoplastic autoimmune disease arising in patients with thymoma.

T cell lymphocytosis associated with polymyositis, myasthenia gravis and thymoma

Peripheral T cell lymphocytosis is a rare finding in association with malignant thymomas. In the majority of previous cases, the tumours have behaved aggressively with symptoms arising from local invasion. We describe a patient with ocular myasthenia gravis who presented with a rapidly progressive polymyositis and neuropathy and who was subsequently found to have a thymic mass and a mild T cell lymphocytosis. The thymoma did not give rise to local symptoms and showed no evidence of progression over a 14-month period of follow-up. The possibility of an underlying thymic tumour should be considered in any patient with chronic T cell lymphocytosis if the circulating cells show mature morphology and there is no molecular evidence of monoclonality.