STAT4

Gene Number: 6775

Location: 2q32.2–q32.3

Key Functions: JAK–STAT signaling, Th1/Th17 differentiation, interferon signaling, cytokine-driven immune activation, autoimmune disease susceptibility

STAT4 encodes Signal Transducer and Activator of Transcription 4, a core transcription factor that helps convert cytokine signals into immune gene-expression programs [R]. It is particularly important downstream of IL-12 and type I interferon signaling, where it promotes Th1-skewed immunity, supports inflammatory cytokine production, and amplifies immune responses that can become pathogenic in autoimmunity [R].

A major role of STAT4 is to promote the development of T helper 1 (Th1) cells. These cells are important for defense against intracellular pathogens such as viruses and some bacteria. STAT4 also helps increase production of interferon-gamma (IFN-γ), a key inflammatory cytokine that strengthens macrophage activation and cellular immunity [R]. In addition, STAT4 contributes to the activity of natural killer (NK) cells and can influence broader immune-cell communication during inflammation [R].

STAT4 activity is most notable in conditions where immune activation is sustained or misdirected. Across large genetic studies, common STAT4 variants—especially those tagging intronic regulatory haplotypes—have been repeatedly associated with rheumatoid arthritis, systemic lupus erythematosus, Sjögren’s syndrome, type 1 diabetes, and primary biliary cholangitis, reflecting a shared inflammatory pathway across autoimmune diseases [R].

Overall, STAT4 is an important immune regulator: it helps the body mount strong protective responses, but when its activity is increased or misdirected, it may also drive chronic inflammation and tissue damage. This makes STAT4 biologically important both for normal host defense and for understanding the molecular basis of autoimmune disease.