Immunological signature of patients with thymic epithelial tumors.

8589 Background: Thymic epithelial tumors (TETs) are complex diseases frequently associated with immune disorders, including Good Syndrome (GS). Etiopathogenesis of immune dysregulations in TETs patients is still not totally explained. The aim of this study was to evaluate differences in immune cell phenotype, as well as in the serum expression levels of a panel of cytokines, chemokines, and growth factors in patients with TETs and GS with or without autoimmune disorders (AD). Methods: From May 2019 to June 2020, consecutive patients with TETs and GS were recruited at Rare Tumors Coordinating Center of Campania Region (CRCTR – Naples, Italy). We analyzed the immunophenotype from peripheral blood focusing on selected immune cell subsets (monocytes, neutrophils, eosinophils, CD4+T cells, CD8+T cells, B-cells, NK cells and NKT- cells, T regulatory cells) processed for blood cell count and immunophenotyping, according to the 8-color immunophenotyping kit and Treg detection kit (CD4/CD25/CD127), and a panel of cytokines, chemokines, and growth factors from peripheral blood serum screened with pre-formed kits by Bioplex multiplex. D’Agostino-Pearson normality test was used to evaluate whether the continuous data were normally distributed, and a two-tailed t-test for independent samples was used. p-values < 0.05 were considered statistically significant. Results: Overall, 29 patients were enrolled [17 (58.6%) with and 12 (41.4%) without AD]. Sixteen patients (55.2%) were female and 13 patients (44.8%) were male. Tumor histology included thymoma in all the patients with AD, whereas there were 10 cases of thymoma and 2 of thymic carcinoma in the group of patients without AD. The analysis of leucocytes by blood cell count showed a statistically significant higher number of leucocytes, ascribable to T lymphocytes (p = 0.023), B lymphopenia (p = 0.003) and decrease of T regulatory cells (p = 0.009) in TET patients with AD, as compared with TET patients without AD. Moreover, TET patients with AD showed significantly higher circulating levels of IL-15 (p = 0.032), VEGF (p = 0.007), IP-10 (p = 0.013), GM-CSF (p = 0.042), IL-6 (p = 0.031), and MIP-1α (p = 0.017) with respect to TET patients without AD. Conclusions: To our knowledge, this is the first report describing a profound alteration in B and T lymphocytes in TET patients associated with AD. The observed differences may be potentially important in the clinical management of this complex disease. Additional studies are needed to better understand the immunophenotypic alterations in TETs patients.