Impaired seroconversion after SARS-CoV-2 mRNA vaccine in patients with thymic epithelial tumors

Abstract

Introduction

Thymic epithelial tumors (TETs) are rare malignancies associated with dysregulation of the immune system and humoral and cell mediated immunity abnormalities. Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) mRNA vaccine is effective in preventing COVID-19 morbidity and mortality. The aim of this study was to evaluate the seroconversion in TET patients after two doses of mRNA vaccine.

Methods

This is a prospective study where consecutive TET patients were enrolled before receiving the first dose of SARS-CoV-2 mRNA vaccine (BNT162b2 by Pfizer-BioNTech). SARS-CoV-2 spike-binding IgG antibody (Ab) serological levels were analyzed at different time-points, including before first vaccine dose (T0), 1 month after 2^nd dose (T2) and 3 months after 2^nd dose (T3).

Results

Overall, 39 patients were included in the analysis. All patients had negative Ab titers at T0. Nineteen (48.7%) patients were in follow-up with no residual tumor lesion/s [referred as no evidence of disease (NED)], and 20 (51.3%) had evidence of disease (ED) and were receiving systemic treatment. Dysregulations of the immune system were diagnosed in 29 patients (74.4%) with Good’s Syndrome (GS) being the most frequent immune disorder (48.7 %). At univariate analysis lack of seroconversion at T2 was significantly associated with ED (p<0.001) and with GS (p= 0.043). A significant association with impaired seroconversion was confirmed at multivariate analysis for ED p=0.00101 but not for GS (p= 0.625).

Conclusions

Our data showed that TET patients with ED had substantially higher probability of impaired seroconversion after SARS-CoV-2 mRNA vaccine as compared with NED patients.