血浆游离DNA IgH和TCRγ基因重排在非霍奇金淋巴瘤患者微小残留病中的应用及临床意义

Clinical significance of Ig heavy chain and TCRγ gene rearrangement detected in plasma cell-free DNA from patients with non-Hodgkin lymphoma and application to monitor MRD

目的检测非霍奇金淋巴瘤(NHL)患者外周血血浆游离DNA免疫球蛋白重链(IgH)基因和T细胞受体γ(TCRγ)基因克隆性重排,并探讨其在监测微小残留病变(MRD)中的临床意义。方法提取63例NHL患者血浆游离DNA并以Globin基因确定其存在,通过PCR方法检测IgH(VH FR3-JH)和TCRγ(Vγ-Jγ)克隆性基因重排,与病理组织学检查进行比较。并随访患者以监测和检测MRD。结果 63例中有49例[30例B细胞NHL(B-NHL)和19例T细胞NHL(T-NHL)]初诊、难治或复发的患者血浆游离DNA提取成功。30例确诊的B-NHL患者中IgH基因单克隆重排阳性27例(90%),19例确诊的T-NHL患者中TCRγ基因单克隆重排阳性14例(74%);其病理活检标本基因重排结果分别为87%和74%(P>0.05)。另14例(9例B-NHL,5例T-NHL)临床缓解患者中,仅1例(B-NHL)提取出血浆游离DNA并检测到IgH基因单克隆重排。随访治疗缓解的患者共56例,其中24例患者血浆游离DNA基因重排持续阴性,2年存活率达83%;27例患者血浆游离DNA基因重排缓解时呈阴性随后转阳,5例患者缓解后始终能检测到血浆游离DNA基因重排,其2年存活率分别为26%和20%(P<0.05)。结论 NHL患者血浆中可以检测出肿瘤源性的血浆游离DNA;NHL患者血浆游离DNA IgH、TCRγ基因重排的检测简单、方便,与病理活检标本检测具有相同的临床意义。在MRD的监测中,利用血浆游离DNA检测单克隆性重排具有一定的早期预测复发的作用。

Objective To evaluate the clinical significance of IgH and TCRγ gene rearrangement in plasma cell-free DNA from the patients with non-Hodgkin lymphoma（NHL） and application to monitor minimal residual disease （MRD）.Methods Plasma cell-free DNA in 63 patients with NHL was extracted and identified by Globin gene.IgH（VH FR3-JH） and TCRγ（Vγ-Jγ） were amplified by PCR and compared with results of pathological biopsy samples DNA.And they were detected and monitored in follow up.Results Plasma cell-free DNA as successfully obtained from 49 cases（30 B-NHL cases and 19 T-NHL cases） of incipient,refractory and relapsed NHL in 63 patients.Out of 30 B-NHL cases,27 cases showed IgH rearrangement（90%）; in 19 T-NHL cases,14 showed TCRγ rearrangement（74%）.Compared with the results of IgH and TCRγ gene rearrangement of biopsy samples,it was 87% and 74% respectively （P〈0.05）.But plasma cell-free DNA was found only in 1 patient of the other 14 remissioned patients.In 2-year follow-up of 56 remittent patients,the survival rate of rearrangement negative group （24 cases） detected by plasma cell-free DNA was 83%.However,it was 26% and 20% for turning to positive group （27 cases） and persistent positive group （5 cases） respectively（P〈0.05）.Conclusion Tumor-derived DNA could be detected in plasma of underlying cancer patients.For NHL patients,detecting IgH and TCRγ gene rearrangement of plasma cell-free DNA has the same clinical significance as biopsy samples.Moreover,it is more convenient and simple.In monitoring MRD,detection monoclonal rearrangement by plasma cell-free DNA plays some role in early forecast of relapse.