Larsen Margit Hørup, Albrechtsen Anders, Thørner Lise Wegner, Werge Thomas, Hansen Thomas, Gether Ulrik, Haastrup Eva, Ullum Henrik
Department of Clinical Immunology, Copenhagen University Hospital, Copenhagen, Denmark.
PLoS One. 2013 Jun 18;8(6):e66262. doi: 10.1371/journal.pone.0066262. Print 2013.
Cytokine response plays a vital role in various human lipopolysaccharide (LPS) infectious and inflammatory diseases. This study aimed to find genetic variants that might affect the levels of LPS-induced interleukin (IL)-6, IL-8, IL-10, IL-1ra and tumor necrosis factor (TNF)-α cytokine production.
We performed an initial genome-wide association study using Affymetrix Human Mapping 500 K GeneChip® to screen 130 healthy individuals of Danish descent. The levels of IL-6, IL-8, IL-10, IL-1ra and TNF-α in 24-hour LPS-stimulated whole blood samples were compared within different genotypes. The 152 most significant SNPs were replicated using Illumina Golden Gate® GeneChip in an independent cohort of 186 Danish individuals. Next, 9 of the most statistical significant SNPs were replicated using PCR-based genotyping in an independent cohort of 400 Danish individuals. All results were analyzed in a combined study among the 716 Danish individuals.
Only one marker of the 500 K Gene Chip in the discovery study showed a significant association with LPS-induced IL-1ra cytokine levels after Bonferroni correction (P<10(-7)). However, this SNP was not associated with the IL-1ra cytokine levels in the replication dataset. No SNPs reached genome-wide significance for the five cytokine levels in the combined analysis of all three stages.
The associations between the genetic variants and the LPS-induced IL-6, IL-8, IL-10, IL-1ra and TNF-α cytokine levels were not significant in the meta-analysis. This present study does not support a strong genetic effect of LPS-stimulated cytokine production; however, the potential for type II errors should be considered.
细胞因子反应在各种人类脂多糖（LPS）感染性和炎症性疾病中起着至关重要的作用。本研究旨在寻找可能影响LPS诱导的白细胞介素（IL）-6、IL-8、IL-10、IL-1受体拮抗剂（IL-1ra）和肿瘤坏死因子（TNF）-α细胞因子产生水平的基因变异。
我们使用Affymetrix Human Mapping 500 K GeneChip®进行了一项初始全基因组关联研究，以筛选130名丹麦血统的健康个体。比较了不同基因型的24小时LPS刺激全血样本中IL-6、IL-8、IL-10、IL-1ra和TNF-α的水平。在186名丹麦个体的独立队列中，使用Illumina Golden Gate® GeneChip对152个最显著的单核苷酸多态性（SNP）进行了重复验证。接下来，在400名丹麦个体的独立队列中，使用基于聚合酶链反应（PCR）的基因分型对9个统计学上最显著的SNP进行了重复验证。所有结果在716名丹麦个体的联合研究中进行了分析。
在发现研究中，500 K基因芯片的仅一个标记在Bonferroni校正后显示与LPS诱导的IL-1ra细胞因子水平有显著关联（P<10(-7)）。然而，该SNP与重复数据集中的IL-1ra细胞因子水平无关。在所有三个阶段的联合分析中，没有SNP达到全基因组显著性水平，涉及这五种细胞因子水平。
在荟萃分析中，基因变异与LPS诱导的IL-6、IL-8、IL-10、IL-1ra和TNF-α细胞因子水平之间的关联不显著。本研究不支持LPS刺激的细胞因子产生具有强大的遗传效应；然而，应考虑II类错误的可能性。
