Expansion of peripheral and intratumoral regulatory T-cells in hepatocellular carcinoma: a case-control study.

BACKGROUND

Hepatocellular carcinoma (HCC) is notorious for poor prognosis with limited therapeutic options. A better understanding of the role of regulatory T-cells (Tregs) in HCC is important for design of immunotherapy based clinical protocol. The objective of the present study was to evaluate the presence of Tregs in tumor microenvironment in patients with HCC compared to chronic hepatitis (CH).

MATERIALS AND METHODS

The frequency of CD4 + CD25 + Treg cells was evaluated from peripheral blood (PB) of 28 patients of HCC and 30 controls including CH cases and healthy donors using flowcytometry. Intratumoral Treg were also analyzed in tissue samples from 17 HCC cases and 15 CH cases. In addition the expression of FOXP3 and CTLA-4 was also studied by RT-PCR.

RESULTS

Frequency of CD4 + CD25 + cells in the PBMCs of HCC cases was significantly higher than in HC (10.8 ± 7.64 vs 3.05 ± 1.30, P < 0.005) and CH patients (2.88 ± 1.92, P < 0.005). Also Treg population was significantly higher in HCC tumor microenvironment compared to CH biopsies (15.8 ± 5.32 vs 5.51 ± 3.40, P < 0.05). Expression of FOXP3 and CTLA-4 was also significantly higher in HCC patients ( P < 0.05) compared to CH group.

CONCLUSIONS

We provide evidence of an increased population of Treg not only in the PB but also in tumor microenvironment of HCC patients, suggesting association of enhanced Treg activity with poor immune responses to tumor antigens. These findings may in future play a significant role in designing immunotherapeutic approaches in HCC.