The STAT4 gene provides instructions for a protein that acts as a transcription factor, which means that it attaches (binds) to specific regions of DNA and helps control the activity of certain genes. The STAT4 protein is turned on (activated) by immune system proteins called cytokines, which are part of the inflammatory response to fight infection. When activated, the STAT4 protein increases the activity of genes that help immune cells called T-cells mature into specialized T-cells. These specialised T-cells, called Th1 cells, produce specific cytokines and stimulate other immune cells to get rid of foreign invaders (pathogens) in the cell.
If you carry a medium to high impact genetic variation in this gene, you may be predisposed to autoimmune diseases such as arthritis and Lupus. It is important that you "add in" choices that support the down-regulation of this genetic pathway. A diet high in silymarin and resveratrol can support down-regulation. Melatonin has also shown to decrease expression in this gene. Curcumin, toxicity, and estrogen has been shown to increase the expression in the gene.