四聚体技术检测原发性胆汁性肝硬化患者血循环中抗原特异性T细胞

目的定量检测原发性胆汁性肝硬化(PBC)患者体内抗原特异性T淋巴细胞含量,探讨其在PBC发病机制中的作用。方法采用四聚体技术检测15例HLA-A0201阳性(A2 )PBC患者外周血单个核细胞(PBMC)经抗原肽诱导生长的细胞毒性T淋巴细胞(CTL)中PDC-E2159~167aa与PDC-E2165~174aa特异性CD8 T细胞频率,以A0201阴性(A2-)PBC患者与A2 的其他慢性肝病和健康自愿者为对照组。结果在A2 PBC患者PDC-E2159~167aa与PDC-E2165~174aa诱导的CTL中可检测到其相应的四聚体/CD8 细胞,平均频率分别为0.42%±0.24%(0.17%~1.08%)、0.27%±0.17%(0.05%~0.56%),各对照组的四聚体阳性细胞频率均低于0.1%,差异非常显著(P<0.001);A2 PBC组中PDC-E2159~167aa特异性的CTL频率与PDC-E2165~174aa特异性的CTL无显著性差异(P>0.05)。处于临床Ⅰ、Ⅱ期的A2 PBC患者中CD8 特异性CTL频率均较Ⅲ期的要高(P<0.05)。PDC-E2159~167aa特异性CTL与PDC-E2165~174aa特异性CTL频率在抗-PDC阳性PBC组和抗-PDC阴性组之间均无显著性差异(P>0.05)。结论HLA-A0201限制性的PDC-E2159~167aa和PDC-E2165~174aa特异性CD8 CTL在PBC疾病进展中起重要作用,抗线粒体抗体阴性或抗-PDC阴性PBC患者与阳性患者可能有着相似的T细胞介导的免疫发病机制。

Quantitation of antigen specific T lymphocytes in peripheral blood of patients with primary biliary cirrhosis using tetramer technology

AIM: To quantitate antigen specific T lymphocytes in peripheral blood from patients with primary biliary cirrhosis(PBC) and study the role of antigen specific T lymphocytes in the development of PBC. METHODS: Using tetramers and CD8 monoclonal antibody staining, PDC-E2 159-167aa and PDC-E2 165-174aa specific CD8(+) T lymphocytes were determined respectively in the peptide-induced cytotoxic T cell lines prepared from peripheral blood mononuclear cells(PBMC) of 15 PBC patients. The frequencies of these two kinds of antigen specific T lymphocytes in HLA-A*0201 positive (A2(+)) PBC were compared with those in A2(-) PBC patients, patients with other A2(+) chronic liver diseases and healthy controls. RESULTS: PDC-E2 159-167aa/HLA-A*0201 and PDC-E2 165-174aa/HLA-A*0201 tetramer positive CD8(+) T lymphocytes were detected in all of A2(+) PBC patients with average percentages of 0.42%+/-0.24% (0.17%-1.08%) and 0.27%+/-0.17% (0.05%-0.56%), respectively. The frequencies of the two kinds of antigen specific CD8(+) T lymphocytes from peripheral blood were significantly higher in earlier stages I and II of PBC as compared with stage III (P<0.001), while no difference was found between PDC-E2 159-167aa and PDC-E2 165-174aa specific CD8(+) T lymphocytes at the same stages. In addition, there existed no statistical difference between frequencies of antigen specific T lymphocytes in AMA or anti-PDC positive and negative PBC patients (P>0.05). CONCLUSION: This study suggests that HLA-A*0201 restricted PDC-E2 165-174aa and PDC-E2 159-167aa specific CTL play important roles in the development of PBC, and there might be a similar mechanism of T cell-mediated damage between AMA or anti-PDC positive and negative PBC patients.