TCF7 and COVID-19: Among others, cytokine-related genes IL12B and TNFSF10 and members of the Krüppel-like factors (KLF) and CCAAT/enhancer-binding protein (CEBP) family of transcription factors as well as transcription factor 7 (TCF7) were affected only in COVID-19-derived PBMCs (Figure 5B).