Meyers Eline, Van Biesen Natalja, De Rop Liselore, De Burghgraeve Tine, Digregorio Marina, Buret Laëtitia, Coenen Samuel, Scholtes Beatrice, Verbakel Jan Y, Heytens Stefan, Cools Piet
Department of Diagnostic Sciences, Faculty of Medicine and Health Sciences, Ghent University, 9000 Ghent, Belgium.
LUHTAR, Leuven Unit for HTA Research, Department of Public Health and Primary Care, KU Leuven, 3000 Leuven, Belgium.
Vaccines (Basel). 2025 Aug 19;13(8):874. doi: 10.3390/vaccines13080874.
T-cell receptor excision circles (TRECs) and kappa-deleting recombination excision circles (KRECs) are markers of recent thymic and bone marrow output, respectively. As they have previously been associated with immunosenescence, we aimed to investigate their association with anti-spike SARS-CoV-2 (S1RBD) IgG antibody response after COVID-19 vaccination in nursing home residents (NHRs) and staff (NHS).
We measured TREC and KREC levels and S1RBD IgG antibody levels from dried blood spots (DBSs) using in-house qPCRs and a commercial ELISA kit, respectively, in 200 participants (50 NHRs and 150 NHS). DBSs were collected in April 2021, approximately two months after primary course COVID-19 vaccination (BNT162b2). We assessed the association between TREC and KREC as dependent variables and age, sex, infection-priming status, and post-vaccination S1RBD-specific IgG concentrations as independent variables by simple and multiple linear regression.
TREC and KREC levels were significantly lower in NHRs compared with NHS and were negatively correlated with age ( < 0.001). Neither TREC nor KREC levels were significantly associated with SARS-CoV-2 antibody concentrations ( > 0.05).
In our study population, TREC and KREC levels decreased with age and were statistically significantly lower in NHRs than NHS. They were, however, not associated with the antibody response after COVID-19 vaccination. Yet, additional research is warranted to explore their potential relevance in cellular immune responses or in combination with other biomarkers of immune function.
T细胞受体切除环（TRECs）和κ链缺失重组切除环（KRECs）分别是近期胸腺和骨髓输出的标志物。由于它们此前已与免疫衰老相关，我们旨在研究它们与养老院居民（NHRs）和工作人员（NHS）接种新冠疫苗后针对严重急性呼吸综合征冠状病毒2刺突蛋白（S1RBD）的IgG抗体反应之间的关联。
我们分别使用内部定量聚合酶链反应（qPCR）和商用酶联免疫吸附测定（ELISA）试剂盒，测量了200名参与者（50名NHRs和150名NHS）干血斑（DBSs）中的TREC和KREC水平以及S1RBD IgG抗体水平。DBSs于2021年4月采集，约在新冠疫苗（BNT162b2）基础免疫接种后两个月。我们通过简单线性回归和多元线性回归，评估了以TREC和KREC为因变量，年龄、性别、感染启动状态以及接种疫苗后S1RBD特异性IgG浓度为自变量之间的关联。
与NHS相比，NHRs中的TREC和KREC水平显著更低，且与年龄呈负相关（<0.001）。TREC和KREC水平均与严重急性呼吸综合征冠状病毒2抗体浓度无显著关联（>0.05）。
在我们的研究人群中，TREC和KREC水平随年龄下降，且NHRs中的水平在统计学上显著低于NHS。然而，它们与新冠疫苗接种后的抗体反应无关。不过，仍有必要开展进一步研究，以探索它们在细胞免疫反应中或与其他免疫功能生物标志物联合时的潜在相关性。
