肝细胞癌组织ICOS+T细胞的多重免疫组织化学检测及其预后价值研究

背景与目的：诱导共刺激分子（inducible costimulator，ICOS）属于B7-CD28免疫球蛋白超家族成员，表达于活化T细胞表面，在T细胞的激活和免疫应答中发挥重要作用；但目前对于ICOS及ICOS+ T细胞在肝细胞癌（hepatocellular carcinoma，HCC）肿瘤组织中的表达及其意义尚不清楚。该研究旨在测定ICOS、ICOS⁺ T细胞在HCC患者肿瘤组织中的表达情况并探讨其预后价值。方法：应用组织芯片（tissue microarrays，TMAs）和多重免疫组织化学技术（multiplex immunohistochemistry，mIHC）检测2006—2007年在复旦大学附属中山医院接受手术治疗的358例原发性HCC患者肿瘤组织和癌旁组织中ICOS⁺细胞、ICOS⁺CD4⁺及ICOS⁺CD8⁺ T细胞的浸润密度和ICOS⁺细胞占CD4⁺、CD8⁺ T细胞的百分比。应用Kaplan-Meier法和多因素COX回归模型分析上述指标对患者预后的影响。结果：与癌旁组织相比，ICOS⁺细胞和ICOS⁺CD4⁺ T细胞在肿瘤组织中浸润数量显著增加（P<0.000 1和P=0.009 1），而ICOS⁺CD8⁺ T细胞则呈相反的降低趋势（P=0.033）；在肿瘤中，ICOS⁺CD4⁺ T细胞的浸润程度显著高于ICOS⁺CD8⁺ T细胞。此外，ICOS⁺CD4⁺和ICOS⁺CD8⁺ T细胞占各自T细胞亚群的百分比在肿瘤组织中均显著增加（P均<0.000 1）。预后分析发现，肿瘤组织中ICOS⁺细胞、ICOS⁺CD4⁺及ICOS⁺CD8⁺ T细胞浸润高的患者总生存期（overall survival，OS）更长，多因素分析证实上述指标是HCC的独立预后良好因素。结论：ICOS在HCC患者的肿瘤组织中高表达，且ICOS⁺细胞、ICOS⁺CD4⁺及ICOS⁺CD8⁺ T细胞是OS的独立预后良好因素，提示上述指标可作为新的HCC预后免疫标志物。

Detection of ICOS+ T cells by multiplex immunohistochemistry in tumor tissue and its clinical significance in hepatocellular carcinoma

Background and purpose: Inducible costimulator (ICOS) is a member of B7-CD28 immunoglobulin superfamily and expressed on the surface of activated T cells, which plays an important role in T cell activation and effector functions. However, the expression pattern and the significance of ICOS and ICOS⁺ T cells in tumor tissue of hepatocellular carcinoma (HCC) are not defined. To this end, the current study was planned to quantitatively detect the expression of ICOS and ICOS⁺ T cells in the tumor tissue of HCC patients and evaluate their clinical significance. Methods: Tissue microarrays (TMAs) and multiplex immunohistochemistry(mIHC) were used to detect the expression levels of ICOS⁺ cells, ICOS+CD4⁺ and ICOS⁺CD8⁺ T cells in tumor and paracancerous tissues from HCC patients who received surgical treatment in Zhongshan Hospital, Fudan University from 2006 to 2007 (n=358). The clinical prognosis was evaluated by Kaplan-Meier analysis and COX regression analysis. Results: The densities of infiltrating ICOS⁺ and ICOS⁺CD4⁺ T cells were significantly higher in tumor tissue than in paracancerous tissue (P<0.000 1 and P=0.009 1). By contrast, the density of ICOS⁺CD8⁺ T cells was significantly lower in tumor tissue than in paracancerous tissue (P=0.033). Within the tumor tissue, the density of ICOS⁺CD4⁺ T cells was significantly higher compared with ICOS⁺CD8⁺ T cells (P<0.000 1). Moreover, the frequencies of ICOS⁺CD4⁺ and ICOS⁺CD8⁺ T cells in tumor tissue were significantly higher compared with their counterparts in paracancerous tissue (P<0.000 1). Multivariate COX regression analysis identified that ICOS⁺ cells, ICOS⁺CD4⁺ and ICOS⁺CD8⁺ T cells were independent favorable prognostic indices for overall survival (OS). Conclusion: Tumor infiltrating ICOS⁺ cells are greatly elevated in the tumor tissue of HCC, and their abundance is associated with prolonged OS. Thus, ICOS⁺ cells, ICOS⁺CD4⁺ and ICOS⁺CD8⁺ T cells might be used as novel prognostic immune biomarkers for HCC.