Abnormal Th17 T cell proportion Decreased Th17 T cell proportion 2025-04-27T06:24:33Z Abnormal decrease of Th17 cells, commonly characterized through the intracellular synthesis of IL-17 or surface expression of CCR6, measured as proportion of total CD3+CD4+ T cells, usually after stimulation. The stimulation is usually unspecific and may include the use of anti-CD3 beads or antibodies, the use of phorbol-12-myristate-13-acetate (PMA) with ionomycin, or staphylococcal enterotoxin B (SEB). Length of incubation and strength of stimulation may vary between laboratories.