For example, active DNA demethylation mediated by the methylcytosine dioxygenase Tet2, inhibits GC Tfh cell and memory Tfh cell formation during viral infection in coordination with the transcription factors Foxo1 and Runx1 (Baessler et al., 2022, Baessler et al., 2023). Here, RUNX1 is linked to viral infectious disease.