CD28 and Cowden disease: Our previous study showed that the balance of circulating CD8+CD28+ and CD8+CD28– T cells, as well as the CD8+CD28+/CD8+CD28– ratio, played a critical role in intestinal immunity, suggesting that a high level of blood CD8+CD28+ T cells is favorable for both patients and rats with UC.[5,7] Furthermore, we hypothesized that the CD8+CD28+/CD8+CD28– ratio plays a significant role in prognosis; thus, we arranged a follow-up for the patients with complicated CD at 30 weeks after diagnosis.