blood interleukin amount blood interleukin-9 amount circulating T-Cell Growth Factor P40 level EFO:0008192 VT:0008628 The proportion, quantity, or volume in whole blood, serum, or plasma of a multifunctional cytokine secreted by primarily by activated TH2 cells that may play a role as a regulator of allergic inflammation, and has been shown to enhance the growth and differentiation of mast cells, and can act on a variety of other immune cells. Trait.ontology CMO:0003068 interleukin 9 measurement EFO:0802663 circulating P40 T-Cell Growth Factor level circulating IL-9 level circulating IL9 level circulating interleukin-9 level