目的　探讨中国南方汉族人 β- defensin- 1基因多态性与慢性阻塞性肺疾病 (COPD)易感性的关系。方法　采用限制性片段长度多态性 (RFLP)技术检测 β defensin -1外显子 2基因型在 12 0例COPD吸烟患者和10 8例非COPD吸烟者中的频率。结果　COPD组同源野生型 (G/G)、杂合型 (G/A)和同源突变型 (A/A)频率分别为 82 .5 0 %、10 .83%和 6 .6 7% ,非COPD组的频率分别为 95 .37%、3.70 %和 0 .93% ,两组基因频率分布的差异有显著性 (P <0 .0 1)。两组等位基因的分布差异也有显著性 (等位基因G频率分别为 87.92 %∶97.2 2 % ;等位基因A频率分别为 12 .0 8%∶2 .78% ;P <0 .0 1) ;G→A的突变率随COPD病情的严重度增加而上升。结论　β defensin 1基因外显子 2的 16 5 4位多态性与中国南方汉族人群COPD易感性可能有关 ,而且可能还影响COPD的进展。 Objective To investigate the relationship between β-defensin-1 gene polymorphism and susceptibility to chronic obstructive pulmonary disease (COPD) in southern Chinese Han population. Methods The frequency of β defensin -1 exon 2 genotypes was detected in 122 COPD smokers and 108 non-COPD smokers using restriction fragment length polymorphism (RFLP). Results The frequencies of homologous wild type (G / G), heterozygous (G / A) and homologous mutation (A / A) in COPD group were 82.5%, 10.83% and 6.76% . The frequencies of non-COPD patients were 95.37%, 3.70% and 0.93%, respectively. There was significant difference between the two groups in gene frequency distribution (P <0.01). There were also significant differences in allele distribution between the two groups (allele G frequency was 87.92%: 97.2 2%, allele A frequency was 12.08%: 2.78%, P <0.01 ); The mutation rate of G → A increased with the severity of COPD. Conclusion The 16 5 4 polymorphism of exon 2 of β defensin 1 gene may be related to COPD susceptibility in Han population of southern China, and may also affect the progress of COPD.