Abstract 1904P
Background
Thymic epithelium is characterized by “promiscuous gene expression” for the process of negative selection, suggesting that the immunomodulatory system is completely destabilized. As result, several immunological dysregulations, twisting between immunodeficiencies sush as Good syndrome (GS) and autoimmune diseases (AD), can occur in thymic epithelial tumors (TETs). Our study aims to address differences in immune cell subsets of patients affected by TETs with and without associated AD.
Methods
11 patients with TET and 11 patients with TET and AD were prospectively recruited at the Rare Tumour Reference Centre of Federico II of Naples from June 2019. Immunophenotype was evaluated on whole blood by immunophenotyping kit and Treg detection kit (CD4/CD25/CD127), focusing on the following cell subsets: monocytes, neutrophils, eosinophils, CD4+T cells, CD8+T cells, B-cells, natural killer (NK) cells and NKT- cells. The mean ± standard deviation of the two group of patients was calculated evaluating the statistical difference in the various cell subsets. Serum levels of Interleukin-15 (IL-15) and Vascular Endothelial Growth Factor (VEGF) were assessed by ELISA-based assays.
Results
A marked difference between the two groups of patients was detected. The leucocytes number was increased in patients with AD (p = 0.01), as well as the percentage of CD3+ (p = 0.04), CD4+ (p = 0.04) and CD8+ (p = 0.03) T lymphocytes. Circulating IL-15 (p = 0.05) and VEGF (p = 0.02) levels were also significantly elevated. Conversely, the percentage of Treg was substantially reduced in patients with AD with median value of 3.5 vs 8.5 without AD (p = 0.0003). Interestingly, CD19+ B cells were decreased in patients with AD (p = 0.05), although B cells reduction was more marked in presence of GS.
Conclusions
Our study suggests that immune-profiles of patients with both thymic malignancies and autoimmunity disorders are similar regardlessthe the type of AD. Intriguingly, these immune-profiles mimic those of TETs patients responding to immune-checkpoints inhibitors, with relative high toxicity. This observation is hypothesis generating for treatment selection in TETs.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
CRCTR Rare Tumors Reference Center of Campania Region.
Funding
Has not received any funding.
Disclosure
M. Giuliano: Advisory/Consultancy, Speaker Bureau/Expert testimony: Lilly; Advisory/Consultancy, Speaker Bureau/Expert testimony: Celgene; Advisory/Consultancy, Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: Novartis Pharma SAS; Advisory/Consultancy, Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: Pfizer Pharmaceutical Israel; Speaker Bureau/Expert testimony: Istituto Gentili; Speaker Bureau/Expert testimony: Eisai Europe Ltd; Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: Roche. B. Daniele: Honoraria (institution), Advisory/Consultancy: Eisai; Honoraria (institution), Advisory/Consultancy: Ipsen; Advisory/Consultancy: Incyte; Advisory/Consultancy, Travel/Accommodation/Expenses: Sanofi; Honoraria (institution), Advisory/Consultancy: MSD; Honoraria (institution), Travel/Accommodation/Expenses: Bayer; Travel/Accommodation/Expenses: Bristol-Myers Squibb; Honoraria (institution): Lilly; Honoraria (institution): AstraZeneca. S. De Placido: Advisory/Consultancy, Speaker Bureau/Expert testimony: Celgene; Advisory/Consultancy, Speaker Bureau/Expert testimony: AstraZeneca; Advisory/Consultancy, Speaker Bureau/Expert testimony: Novartis Pharma SAS; Advisory/Consultancy, Speaker Bureau/Expert testimony: Pfizer Pharmaceutical Israel; Advisory/Consultancy, Speaker Bureau/Expert testimony: Roche. All other authors have declared no conflicts of interest.