Cytokines

Cytokines are small proteins used by cells — especially immune cells — to communicate with one another and coordinate immune and inflammatory responses. Cytokines can signal immune cells to become more or less active and can influence processes throughout the body and brain. Some promote inflammation, while others help limit or regulate it. Researchers measure certain cytokines in blood as biomarkers of immune activity and study changes in cytokine levels in many physical and psychiatric conditions, including bipolar disorder. A cytokine finding by itself doesn’t establish what caused the change or whether it caused an illness.