Recently, we reported that there exists a significant positive correlation between serum IL‐10 levels and the percentage of Treg cells in the CD4+ T‐cell population in patients with postoperative infections, and that septic injury induced by cecal ligation and puncture increases the percentage of Treg cells among CD4+ T cells in the spleen, and there was a significant positive correlation between the percentage of Treg cells and serum IL‐10 or TGF‐β levels. The gene discussed is CD4; the disease is infection.