中国人群慢性淋巴细胞白血病免疫球蛋白重链可变区基因组成及突变分析

目的 研究中国慢性淋巴细胞白血病(chronic lymphocytic leukemia,CLL)患者免疫球蛋白重链可变区(immunoglobulin variable heavy chain region,IGVH)基因各个片段的组成以及突变情况.方法 应用多重PCR技术扩增64例CLL患者的IGVH基因片段,纯化PCR扩增产物后直接测序,应用IMGT/V-QUEST及IGBlast数据库分析,明确VH基因有无突变和突变位置,以及VH、DH,JH家族各个成员组成情况.结果 64例CLL患者中,VH3家族31例(48%)、VH4家族26例(41%)、VH1家族4例(6%)、VH2家族2例(3%)、VH7家族1例(2%).44例患者发生体细胞突变,占CLL患者的69%;20例无突变,占CLL患者的31%,其中6例(9%)VH基因的同源性为100%.VH4家族中有9例无突变(9/26,35%);VH3家族中8例无突变(8/31,26%);VH1家族中1例无突变(1/4,25%).在所检测的CLL标本中,VH4-34是最常见的VH基因片段,检测出8例(13%),其中无突变3例;其次为VH4-59,检测出7例(11%),无突变者3例.DH基因中DH3家族最常见,有25例(39%);其中11例(11/20,55%)出现在无突变组中.无突变组中最常见的DH基因片段为DH3-10和DH3-22,各为4例(4/20,20%).JH基因中JH6家族最常见,检测出23例(36%),其中9例出现在无突变组中(9/20,45%).结论 中国CLL患者IGVH基因家族表达比例和突变情况与西方国家存在显著差异,推测可能与不同的种族和环境中的抗原选择有关,其预后意义有待进一步探讨.

Immunoglobulin variable heavy chain region genetic constitution and mutation states in Chinese patients with chronic lymphocytic leukemia

Objective To evaluate the genetic constitution and mutation status of the immunoglobulin variable heavy chain region (IGVH) gene expression in Chinese patients with chronic lymphocytic leukemia (CLL). Methods The IGVH mutation was detected by multiplex PCR and direct sequencing of the purified PCR products from 64 CLL patients. The segments of VH, DH and JH family and mutations were analyzed by IMGT/V-QUEST and IGBlast. Results In the 64 patients, the most common usage was VH3 (31/64, 48%), followed by VH4 (26/64, 41%), VH1 (4/64, 6%), VH2 (2/64, 3%) and VH7 (1/64, 2%). The results also showed that 44 patients (69%) had mutated VH, 6 cases (9%) had identical germline sequences. Among the 64 sequences of DH segments, DH3 gene family was used most frequently (25/64, 39%), among which 11 cases had unmutated VH. The most frequent usage of the JH segments was JH6. Conclusion There is significant difference in the frequency of the IGVH gene family in Chinese CLL patients compared to Western patients, suggesting the involvement of antigen selection in different ethnic and/or environmental factors in CLL disease initiation, and its prognostic significance needs further investigation.