According to our data, such functional imbalance is reflected at the transcriptional level by altered mRNA expression of several genes involved in T cell activation (CSF1, LAT, LTA, CD40LG, JAK1), modulation (BTLA), proliferation (CDK4), and apoptosis (TGFB1, CDK4, TNFSF10, and TNFRSF10A), highlighting the persistence of perturbation of T cell function after clinical remission from COVID-19. The gene discussed is BTLA; the disease is COVID-19.