[Clinical significance of regulatory T cells proportion in the peripheral blood and tumor tissue in primary hepatocellular carcinoma].

OBJECTIVE: To investigate the clinical significance of the amount of regulatory T cells (Treg) in the peripheral blood CD4+ cells and tumor tissue in primary hepatocellular carcinoma (HCC).

METHODS: From January 1999 to December 2000, 63 HCC patients underwent radical resection in Sun Yatsen University Cancer Center. Tregs in those patients were detected in the samples of preoperative peripheral blood by flow cytometry and also in tissue samples of the resected tumors by immunohistochemistry. All patients had been followed up till Dec 30, 2005. The correlations of Treg amount in the peripheral blood CD4+ cells and tumor tissue with clinicopathologic characteristics and prognosis of HCC were analyzed.

RESULTS: The proportion of Treg/CD4+ in the peripheral blood was significantly higher in the patients with HCC than that in those with HBsAg positive (P < 0.01) and in the normal controls (P < 0.01). The mean number of Treg in tumor tissue was (15.69 +/- 13.29)/mm2, but none or very few Treg was detected in the normal liver tissue, para-cancerous liver tissue, and HBV-infected liver tissue. The proportion of Treg/ CD4+ in the peripheral blood was significantly positively correlated with the number of Treg in tumor tissue (P = 0.024). The 5-year survival in patients with high amount of Treg in both peripheral blood and tumor tissue was significantly poorer than that in the patients with low amount of Treg (P = 0.042, 0.019). The 5-year disease-free survival rate was significantly lower in the patients with high amount of Treg in tumor tissue than that in the patients with lower amount (P = 0.001).

CONCLUSION: Regulatory T cells in the circulatory blood and tumor tissue are increased in patients with hepatocellular carcinoma. The increased amount of regulatory T cells either in peripheral blood or in the tumor tissue is pertaining to poor prognosis. Detection of regulatory T cells both in the preoperative peripheral blood CD4+ cells and tumor tissue may be used as a potential immunological prognostic indicator for the hepatocellular carcinoma patients after radical resection.