摘要目的 检测经典型Richter综合征的IgVH基因克隆重排及突变状态,分析转化前后IgVH基因的分子特征及其与预后的关系,并对可能涉及的分子机制进行初步探讨.方法 用基因扫描和测序分析IgVH基因.另外用免疫组织化学LAB-SA法检测两种肿瘤中zeta链结合蛋白激酶70(ZAP70)、p53、干扰紊调节因子(IRF)-4等可能潜在危险因子的表达,并结合随访资料进行生存率分析,筛选危险因子.结果 (1)B-CLL/DLBCL克隆相关(18/23,78.3%),克隆不相关(5/23,21.7%);(2)在16例克隆相关中,12例转化前B-CLL及转化后DLBCL携带未突变IgVH基因;(3)转化前后IgVH基因使用是非随机的,在克隆相关的病例中,B-CLL/DLBCL最常使用VH3-23、VH3-74、VH1-2,各占11.1%;(4)转化后DLBCL仅部分表达CD5(32.1%)和CD23(14.3%)及ZAP70(23.8%),绝大多数表达p53(80.6%)和IRF-4(82.6%);(5)17例转化后DLBCL患者中位生存时间为7个月;(6)统计学分析生存时间与B-CLl/DLBCL转化前后克隆相关与否、IgVH基因的突变状态、ZAP70、p53、IRF-4的表达不相关.结论 (1)转化后DLBCL中克隆相关与克隆不相关的比例为2:1;(2)克隆相关的DLBCL多由携带未突变型IgVH基因的B-CLL患者转化而来;(3)发生转化的B-CLL中IgVH基因使用的偏向性提示了抗原在转化中的可能作用;(4)转化后DLBCL与普通DLBCL在IgVH基因的使用、突变状态,免疫表型及预后的不同,提示其可能是一种新的DLBCL亚类.

abstractsObjective To study the clonal rearrangements and mutation status of IgVH genes in classic Richter's syndrome,the relationship between molecular findings of IgVH gene and clinical outcome,and to deciper the possible molecular mechanism of transformation.Methods The clonal rearrangements and mutation status of IgVH genes were analyzed in cases of classic Richter's syndrome by Genescan and sequencing.Immunohistochemical study for zeta-chain associated protein kinase 70 kDa(ZAP70),p53 and interferon regulation factor 4(IRF-4)was also performed.Results Samples of 18 cases of B-chronic lymphocytic leukemia(B-CLL)/diffuse large B-cell lymphoma(DLBCL,78.3%)had idenfical tumor cell clones.whereas DLBCL developed as a clonally independent neoplasm in 5 patients(21.7%).Among the clonally related group, 12 cases carried unmutated VH genes in both B-CLL and DLBCL components and VH3-23,VH3-74 and VH1-2 were accounted for the B-CLL transformation to DLBCL.Immunohistochemical study showed that the transformed DLBCL expressed CD5 in 32.1%of cases,CD23 in 14.3%, ZAP70 in 23.8%,p53 in 80.6%and IRF-4 in 82.6% of the cases respectively.Follow-up data were available in 17 pailents with classic Richter's syndrome.The median survival period was 7 months.No significant difference in survival rate was obtained between the clonally related or unrelated groups,between IgVH gene mutated or unmutated groups,and between the groups with or without expression of ZAP70,p53 and IRF-4.Conclusions The ratio of clonally related transformed DLBCL from B-CLL to clonally unrelated DLBCL is 2:1.Clonal transformation to DLBCL predominantly occurs in B-CLL patients carrying unmutated IgVH genes.The biased IgVH gene usage suggests antigens are involved in classic Richter's syndrome.Molecular differences of IgVH genes and very poor clinical outcome of this group of transformed DLBCL indicate that there cases may be regarded as a distinct subset of DLBCL.