弥漫大B细胞淋巴瘤中MHC Ⅱ类分子的表达及其意义

Expression of MHC Ⅱ in diffuse large B-cell lymphoma an its significance

目的检测弥漫大B细胞淋巴瘤(diffuse large B-cell lymphoma,DLBCL)中主要组织相容性复合物Ⅱ(major histocompatibility complex classⅡ,MHCⅡ)类分子的表达,探讨其临床病理学意义。方法收集123例DLBCL和30例淋巴结反应性增生(reactive hyperplasia,RH)石蜡标本,采用免疫组化EnVision两步法对DLBCL进行免疫分型,并检测良恶性淋巴组织中MHCⅡ类分子的表达,分析其表达与患者临床病理特征及预后的关系。结果 DLBCL组织中MHCⅡ类分子阳性率(49.5%,61/123)显著低于RH淋巴组织(86.7%,26/30);活化B细胞(activated B-cell-like,ABC)型DLBCL中MHCⅡ阳性率(38%,27/71)显著低于生发中心型B细胞样(germinal center B-cell-like,GCB)(65.3%,34/52)。DLBCL中MHCⅡ类分子的低表达与患者结外病灶受累多、体能状态评分高和国际预后指数评分高危组有关(P均<0.05)。在ABC型DLBCL患者中,MHCⅡ低表达组患者的总生存率明显低于MHCⅡ高表达组患者。ABC型DLBCL中MHCⅡ类分子表达与MUM1表达呈负相关(P<0.01)。结论 MHCⅡ类分子在DLBCL中存在低表达,其异常表达可能在DLBCL发生和浸润中发挥重要作用,其表达丢失提示DLBCL患者预后不良。

Purpose To detect the expression of major histocompatibility complex class Ⅱ （ MHC Ⅱ） molecules in diffuse large B-cell lymphoma （DLBCL） and its clinicopathological significance. Methods 123 cases of DLBCL and 30 cases of benign reactive byperplasia （RH） were collected. DLBCL genotyping was used by immunohistochemical technique （EnVision two-step） and the expression of MHCⅡ in benign and malignant lymphoid tissue was detected. Association between the expression of MHC Ⅱ molecules and clinical pathological features was also analysed. Results The positive rates of MHC Ⅱ were 49. 5% （61/123） in DLBCL tissues, which was significantly lower than that in RH tissues （86.7%, 26/30）. The positive rates of MHC Ⅱ were 38% （27/71） for ABC type DLBCL, which was significantly lower than that in GCB type DLBCL 65.3% （34/52）. The low expression of MHC Ⅱ was correlated with extranodal involvement of multiple lesions, higher ECOG score and high-risk group of international prognostic index （P 〈 0.05 ）. In ABC type DLBCL, the overall survival of low MHC Ⅱ expression patients was significantly lower than high MHC Ⅱ expression patients. The expression of MHC II has inverse correlation with MUM1 in DLBCL （ P 〈 0. 01 ）. Conclusion Low expression of MHC Ⅱ molecules present in DLBCL. Its abnormal expression may play an important role in the progress and infiltration in DLBCL. The loss of its expression may predict poor prognosis in DLBCL patients.