慢性淋巴细胞白血病患者免疫球蛋白重链片段及其突变状态的研究

Overrepresentation of specific gene segments of expressed immunoglobulin heavy chain variable region among unmutated and mutated patients with chronic lymphocytic leukemia

目的探讨我国慢性淋巴细胞白血病（CLL）患者免疫球蛋白重链可变区基因（IgVH）突变状态、基因偏颇性及其预后价值。方法应用多重PCR法检测CLL患者表达型IgVH片段使用情况及突变状态，并与患者生存和预后进行相关性分析。结果①共检测初诊CLL患者85例，80例（94．1％）成功测序。②IgVH片段的使用存在明显的偏颇性，其中常见的为VH3家族（32例，40．0％）、VH4家族（24例，30．0％），而VH5、VH6和VH7家族少见。VH4—39是最常见的VH基因片段。而J4和D3分别是JH家族和DH家族中使用频率最高的片段。③IgVH突变型56例（70．0％），非突变型24例（30．0％）。其中VH3家族突变率为90．7％（29例），VH4家族突变率为62．5％（15例）。④突变组与未突变组患者无进展生存时间（82个月和17个月，P=0．000）和总生存时间（90个月和41个月，P=0．009）差异均有统计学意义。⑤CLL患者IgVHCDR3区序列具重现性，2例VH片段为VH1-69的患者其CDR3序列与文献报道序列有很高的同源性。VH片段为VH1—18、VH3—7、VH3-23的患者中分别有2例CDR3序列完全相同。结论不同地区间CLL患者IgVH基因家族使用情况和突变状态存在一定差异，IgVH CDR3区序列具重现性，推测相对有限的抗原参与了CLL的发病。

Objective To investigate the oven：epresentation of specific gene segments of immunoglobulin heavy chain variable region （IgVH） among unmutated and mutated chronic lymphocytic leukemia （CLL） patients and its prognostic implication. Methods Multiplex PCR was used to identify the expression of IgVH segment and its mutation status in CLL. Results Analyses were successfully performed in 80 of 85 samples. Marked skewed IgVH families were disclosed. The most commonly used VH was VH3 （40.0%） , followed by VH4 （30.0%）, VH1 （ 13.8% ）, VH2 （ 10.0% ） and VH5 ,VH7 （2.5%）. Fifty-six patients （70.0%） had mutated VH, 24 （30.0%） unmutated VH. Nine cases （11.3% ） were with 100% germline sequence. Fifteen cases （ 15/24,62.5% ） in VH4, 29 （ 29/32,90.7% ） in VH3, and 4 （4/11, 36.3% ） in VH1 had mutated VH. The most frequently used IgVH gene was VH4-39 （ 13.8% ） , and VH4-34 （8.8%）. J4（36/66,54.5% ） and D3（25/66,37.8% ）were the most frequently used in J and D genes. The progression-free survival （PFS） was 82 and 17 months （P=0. 000 ） , and the overall survival （OS） was 90 and 41 months（ P = 0. 009） , respectively, for mutated and unmutated eases. Recurrent CDR3 sequences were found in our patients and 2 patients with VH1-69 had CDR3 sequences highly similar to those reported in literature. Conclusion There is difference in IgVH gene segment usage and mutational status in different area CLL patients. Recurrent CDR3 sequences were found in specific IgVH gene segments, which highlights the importance of immunoglobulin mediated stimulation in the development of CLL.