颗粒酶B和穿孔素免疫组织化学检测诊断肝移植急性排斥反应的敏感性与特异性

目的　探讨颗粒酶B和穿孔素两种免疫活化分子在肝移植急性排斥诊断中的作用,及其与Banff急性排斥反应组织学诊断标准之间的对应关系。方法　在常规组织学诊断基础上,将41份肝穿刺标本用颗粒酶B与穿孔素单克隆抗体进行免疫组织化学EnVision二步法标记,IPP图像分析软件计算阳性细胞数/mm2 作为免疫活化细胞指数(AI),以组织学诊断作为评判有无急性排斥反应的标准。结果　在41份肝穿刺标本中,组织学诊断为急性排斥反应21份,缺乏急性排斥反应组织学改变20份。急性排斥反应组颗粒酶B与穿孔素AI值显著高于无排斥反应组(P<0. 001),中重度排斥反应组AI值显著高于轻度及其非确定性排斥反应组(P<0. 001)。与组织学诊断比较,颗粒酶B的敏感性、特异性、阳性预测值、阴性预测值及诊断一致率分别达到90. 0%、95. 2%、94. 7%、90. 9%以及92. 7%;穿孔素的各指标也分别达到80. 0%以上。结论　颗粒酶B与穿孔素是急性排斥反应免疫效应细胞活化标志,在临床肝移植急性排斥反应时表达明显升高,作为组织学诊断急性排斥反应的辅助指标具有相当高的敏感性及特异性,可用于肝移植后肝穿刺标本的鉴别诊断。

Sensitivity and specificity of granzyme B and perforin in diagnosing acute rejection after liver transplantation

OBJECTIVE: To study the roles of granzyme B and perforin in diagnosing acute rejection after liver transplantation, and the relationship between their activity index (AI) and Banff's histological grading criteria. METHODS: Liver biopsies were processed as for routine surgical specimens and labeled with granzyme B and perforin monoclonal antibodies. The number of positive cells/mm(2) was determined as activity index (AI) by IPP image analysis software. Histologic findings were used as the "gold standard" in diagnosing acute rejection. RESULTS: Of 41 liver biopsy samples studied, acute rejection was noted in 21 cases, the remaining 20 cases showed no evidence of rejection. The AI of granzyme B and perforin in the acute rejection group was significantly higher than that in the non-acute rejection group (< 0.001). In the acute rejection group, the AI in moderate to severe acute rejection was higher than that in mild to indeterminate acute rejection (< 0.001). Compared with the "golden" histologic criteria, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of granzyme B in diagnosing acute rejection were 90.0%, 95.2%, 94.7%, 90.9% and 92.7% respectively. The values of these parameters for perforin were also above 80%. CONCLUSIONS: Granzyme B and perforin are key markers of activated immune cells in acute rejection and highly expressed during acute liver rejection episodes. As ancillary investigations, these parameters demonstrated high sensitivity and specificity in diagnosing acute rejection in allograft post-transplant liver biopsies.