AB115. Preliminary study on the immune status of patients with prostate cancer

Objective: To preliminarily assess the immune status of patients with prostate cancer through detecting various immune indexs and then analyse the relationship between immune status and clinical factors such as clinical stage, pathological classification and endocrine therapy.

Methods: Flow cytometry was used to detect the percentage of CD4, CD8and NK cells in peripheral blood lymphocyte (PBL) of 28 patients with PCa, 16 BPH patients and ten healthy men (HM). The expression of perforin and granzyme-B in PBL of 30 patients with PCa, 17 BPH patients and 7 HM were tested by fluorescence quantitative reverse transcription polymerase chain reaction. The results and evaluation of the relationship between these immune indexes and several clinical variables were analysed statistically.

Results: The percentage of CD4lymphocyte and the ratio of CD4/CD8 in PCa group were significantly lower than those in BPH group and HM group while the percentage of CD8lymphocytes in PCa group was statistically higher than that in BPH group and HM group (P<0.05). There are no statistical difference of percentage of NK cells between PCa group, BPH group and HM group (P>0.05). The percentage of CD4lymphocyte and the ratio of CD4/CD8in low pathological grade PCa patients were significantly higher than those in high pathological grade PCa patients while the percentage of CD8 lymphocyte in low pathological grade PCa patients was lower than that in high pathological grade PCa patients (P<0.05). The difference of percentage of NK cells between low pathological grade PCa patients and high pathological grade PCa patients has no statistical significant (P>0.05). The percentage of CD4lymphocyte and the ratio of CD4/CD8 in metastatic PCa group were significantly lower than those in non-metastatic PCa group while the percentage of CD8lymphocytes in metastatic cPCa was higher than that in non-metastatic PCa group (P<0.05). The difference of percentage of NK cells between metastatic PCa group and non-metastatic PCa group has no statistical significant (P>0.05). There is no statistically significant difference between lymphocyte subgroup percentage of T₃PCa group and T₄PCa group (P>0.05). There was no statistical difference of percentage of lymphocyte subgroup in PCa patients whether they received endocrine therapy or not (P>0.05).

Results: The expression of perforin and granzyme-B inPBL was significantly lower in patients with PCa than that in patients with BPH and HM group (P<0.05). Furthermore, in low pathological grade PCa patients, the expression of perforin and granzyme-B in PBL was statistically higher than that in high pathological grade PCa patients (P<0.05). There is no statistical difference between expression of perforin and granzyme-Bin metastatic PCa group and those in non-metastatic PCa group (P>0.05). The difference between expression of perforin and granzyme-B in PCa patients who have not receive endocrine therapy and those in PCa patients who have received endocrine therapy for more than 4 weeks also have no statistical significance (P>0.05). The expression level of perforin and granzyme-B in T₃ PCa group were significantly higher than those inT₄PCa group (P<0.05).

Conclusions: Firstly, compared with BPH patients and healthy men, PCa patients have a lower immunity. Secondly, the degree of immuno-suppression in PCa patients may be related to the degree of tumor malignancy and clinical progress. High grade malignancy and late clinical stage may suggest heavy immunosuppression. Thirdly, Endocrine therapy seems to have no obvious influence on the immune function of PCa patients.

Keywords: Prostate cancer (PCa); lymphocytes; perforin; granzyme-B; CD4; CD8; NK cell