Abnormal Th1 T cell proportion Decreased Th1 T cell proportion 2025-04-27T06:20:37Z Abnormal decrease of Th1 cells, commonly characterized through the intracellular synthesis of IFNg or surface expression of CXCR3, 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 or the use of phorbol-12-myristate-13-acetate (PMA) with ionomycin. Length of incubation and strength of stimulation may vary between laboratories.