Serum biomarkers of inflammation and vascular damage upon SARS-Cov-2 mRNA vaccine in patients with thymic epithelial tumors.

Objectives: Thymic epithelial tumors (TET) patients are at high risk of autoimmune and hypoimmune complications. Limited evidence is available on the potential risk of immune-related and inflammatory reactions induced by SARS-Cov-2 vaccine in this patient population.

Methods: In order to identify subjects at higher risk for vaccine complications, we prospectively evaluated a panel of serum biomarkers related to inflammation (TNF-α, IL-1β, -6, -10, -12, and -17A, IFN-α, β and γ, MPO, MMP-9), and vascular damage (E- and P-selectin, VEGF-A, P-ANCA and MCP-1) in 44 TET patients and in 30 healthy controls along the whole SARS-Cov-2 vaccine cycle.

Results: About 50 % of subjects (either TET and controls) showed an increase of serum biochemical markers of inflammation and endothelial damage with a large heterogeneity of values. Such increase appeared early, after the first dose in control subjects and later, after the second dose in TET patients (in which we observed mainly an increase of inflammatory biomarkers). The values normalized after about 3 months and did not increase after the third, booster dose. No autoimmune or vascular complications were observed in the study subjects and no difference was observed in terms of vaccine response among subjects showing serum biomarkers increase and those who experienced no changes.

Conclusions: Our data highlight the relevance of Sars-Cov-2 vaccine in TET patients, as it resulted safe and prevented severe COVID-19. However, further studies are awaited to explore the mechanisms and the potential consequences of the observed increase of serum inflammatory and vascular damage biomarkers.