The idea that estrogens can influence the clinical course of PBC came from several studies showing that estrogens can modulate the humoral and cellular immune response by stimulation of Th2 anti-inflammatory cytokines (IL-10, IL-4, and TGF-β) and inhibition of Th1 pro-inflammatory cytokines (IL-12, TNF-α, and interferon γ (IFN-γ)) [12,13,14,15]. The gene discussed is TGFB1; the disease is primary biliary cholangitis.