Relationship between dendritic cells and memory T lymphocytes in tumor site and prognosis of hepatocellular carcinoma

Abstract

To investigate the relationship between the distribution and quantity of dendritic cells (DCs) and memory T lymphocytes in the tumor site and the prognosis of hepatocellular carcinoma (HCC). Hematoxilin and eosin staining was done on 123 specimens of pathologically proven HCC to observe the infiltration of lymphocytes. Immunohistochemistry was used to count the S-100 protein positive DCs and CD45RO antigen positive memory T cells in ten high power fields within a specimen. Double immunohistochemical staining with double enzyme renovated by microwave for S-100 protein and CD45RO antigens was used to observe relationship between the positivity of S-100 protein and positivity of CD45RO antigen. The specimens were divided into 4 groups according to the averaged numbers of DCs and memory T cells: group I with the DCs and T cells both >/= average numbers, group II with the DCs >/= T cells and T cells < average number, group III with the DCs < average number and memory T cells >/= average, and group IV with both DCs and T cells < average numbers. HE staining showed that the grade of intratumoral or peritumoral lymphocytes was not correlated with the tumor-free survival rate (P = 0.054, 0.071, both P > 0.05), the number of DCs in the cancerous node (DC >/= 25/10 high power field) was positively correlated with the tumor-free survival rate (P = 0.005) and the number of T cells in the cancerous node was positively correlated with the tumor-free survival rate (P = 0.003). Double staining method of immunohistochemistry showed that in the cancerous nodes the number of CD-100 positive DCs and the number of CD45RO positive memory T cells was significantly correlated (r = 0.531, P = 0.000). A greater number of DCs in the cancerous nodes showed a longer tumor-free survival rate of the patients (P = 0.000 between group I and group IV, P = 0.009 between group II and group IV, and P = 0.545 between group I and group II). The tumor-free survival rate of the patients who had more intratumoral DCs is higher, which indicates that DCs play an important role in activation of T lymphocytes and immune response and can be used as an independent prognostic factor.