A transcriptional signature associated with non-Hodgkin lymphoma in the blood of patients with Q fever. A transcriptional signature associated with non-Hodgkin lymphoma in the blood of patients with Q fever

Coxiella burnetii, the agent causing Q fever, has been associated with B-cell non-Hodgkin lymphoma (NHL). To better clarify this link, we analysed the genetic transcriptomic profile of peripheral blood leukocytes from patients with C. burnetii infection to identify possible links to lymphoma. Microarray analyses revealed that 1189 genes were expressed differently (p <.001 and fold change ≥4) in whole blood of patients with C. burnetii infection compared to controls. In addition, 95 genes expressed in patients with non-Hodgkin lymphoma (NHL) and in patients with C. burnetii persistent infection have allowed us to establish the ‘C. burnetii-associated NHL signature’. Among these, 33 genes previously found modulated in C. burnetii-associated -NHL by the microarray analysis were selected and their mRNA expression levels were measured in distinct C. burnetii-induced pathologies, namely, acute Q fever, focalized persistent infection, lymphadenitis and C.burnetii-associated NHL. Specific genes involved in anti-apoptotic process were found highly expressed in leukocytes from patients with C. burnetii associated-NHL: MIR17HG, REL and SP100. This signature differed from that found for NHL-control group. Patients with C. burnetii lymphadenitis presented significant elevated levels of BCL2 and ETS1 mRNAs. Altogether, we identified a specific transcriptionnal signature for NHL during C. burnetii infection reflecting the up-regulation of anti-apoptotic processes and the fact that lymphadenitis might constitute a critical step towards lymphomagenesis. Overall design: RNAs were extracted from whole blood (PAXgene tubes, Qiagen, Courtaboeuf, France) with PAXgene kit with a DNase I treatment to eliminate DNA contaminants and according to the recommendations of the manufacturer (Qiagen, Courtaboeuf, France)

贝氏柯克斯体（Coxiella burnetii）是引发Q热（Q fever）的病原体，既往研究已发现其与B细胞非霍奇金淋巴瘤（non-Hodgkin lymphoma, NHL）存在关联。为进一步明确二者间的潜在联系，本研究对贝氏柯克斯体感染患者外周血白细胞的遗传转录组谱进行了分析，以探寻其与淋巴瘤的潜在关联。基因芯片分析结果显示，与健康对照组相比，贝氏柯克斯体感染患者的全血样本中共有1189个基因存在差异表达（p < 0.001，且表达倍数变化≥4）。此外，通过比对非霍奇金淋巴瘤患者与贝氏柯克斯体持续感染患者的基因表达谱，我们成功构建了“贝氏柯克斯体相关非霍奇金淋巴瘤特征基因集”。其中，33个此前经基因芯片分析发现于贝氏柯克斯体相关非霍奇金淋巴瘤中存在表达调控的基因被筛选出来，并针对不同贝氏柯克斯体诱导的病理状态——包括急性Q热、局灶性持续感染、淋巴结炎以及贝氏柯克斯体相关非霍奇金淋巴瘤——检测了这些基因的信使RNA（mRNA）表达水平。研究发现，贝氏柯克斯体相关非霍奇金淋巴瘤患者的白细胞中，参与抗凋亡过程的特定基因呈现显著高表达，包括MIR17HG、REL及SP100。该特征基因集与非霍奇金淋巴瘤对照组的特征存在明显差异。贝氏柯克斯体淋巴结炎患者的BCL2与ETS1 mRNA水平则显著升高。综上，本研究鉴定出贝氏柯克斯体感染期间非霍奇金淋巴瘤的特异性转录特征，该特征反映了抗凋亡过程的上调，同时提示淋巴结炎可能是淋巴瘤发生过程中的关键环节。本研究的整体实验设计如下：采用PAXgene采血管（Qiagen, 法国库尔泰博伊）采集全血样本，依照制造商（Qiagen, 法国库尔泰博伊）的操作指南，使用PAXgene试剂盒提取RNA，并通过DNase I处理以去除DNA污染物。