STAT4 mRNA levels and half-life of STAT4 mRNA in PBMCs. PBMCs obtained from 6 healthy control subjects and 3 patients after high-dose chemotherapy and PBSCT were treated with actinomycin D at 1 μg/mL for 0, 2, 4, and 6 hours in a 5% CO₂ incubator at 37°C. RNA was extracted and first-strand cDNA was synthesized, followed by the real-time PCR.²⁵  The half-life of STAT4 mRNA from each sample was calculated accordingly.²⁵  Results shown are means ± SD.