BCL6 is a zinc finger-containing transcription factor, which acts as a sequence-specific repressor of transcription, and has been shown to modulate the transcription of STAT-dependent IL-4 responses of B cells. On B cells, BCL6 induces proliferation, antibody class switching and affinity maturation, whereas it inhibits their differentiation into plasma cells. On T cells, BCL6 induces their differentiation into T-FH cells.