Interleukin 5 Unit Converter

Interleukin-5 (IL-5) is a signaling protein (cytokine) that plays a central role in controlling eosinophils, a type of white blood cell involved in allergic reactions, parasitic defense, and inflammation.

When measured in blood, the test quantifies IL-5 protein concentration in serum or plasma and is reported in pg/mL (equivalent to ng/L). Healthy individuals typically have very low or undetectable levels.

IL-5 is often measured alongside other Th2 cytokines such as IL-4 and IL-13, as well as blood eosinophil counts and total IgE, to build a picture of type 2 (allergic) inflammation.

IL-5 is produced primarily by type 2 helper T cells (Th2 cells) and group 2 innate lymphoid cells (ILC2s) in response to allergens, infections, or tissue damage. Eosinophils, mast cells, and natural killer T cells also produce smaller amounts.