Systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) are influenced by genetic variants in immune system HLA genes. The Class II Major Histocompatibility Complex Transactivator (CIITA) is an important co-activator of the HLA transcriptional complex; the single nucleotide variant (SNV) rs3087456 localized in the gene promoter region (−168 A/G) has been reported as able to modify its transcription level. In our study, we assessed CIITA rs3087456 SNV in 1,044 Brazilians from two Brazilian regions (Northeast and South) to verify the association with susceptibility and clinical manifestations of (SLE) and (RA) using TaqMan SNP Genotyping Assays System. We observed a protection for a recessive model (GG x AA+AG) for RA susceptibility and increased risk for erosion development in AG genotype patients. No significant association was observed for SLE susceptibility; however, we observed significant increased risk for Class IV and V nephritis development in G allele and GG genotype patients. In conclusion, we showed the contribution of CIITA rs3087456 to SLE or RA clinical features and RA susceptibility in the studied populations.

中文翻译：

---

系统性红斑狼疮和类风湿关节炎的 CIITA 基因多态性 (rs3087456)：基于人群的队列研究

系统性红斑狼疮 (SLE) 和类风湿性关节炎 (RA) 受免疫系统 HLA 基因的遗传变异影响。II 类主要组织相容性复合物反式激活因子 (CIITA) 是 HLA 转录复合物的重要共激活因子；据报道，位于基因启动子区域（-168 A/G）的单核苷酸变体（SNV）rs3087456能够改变其转录水平。在我们的研究中，我们评估了CIITArs3087456 SNV 在来自巴西两个地区（东北部和南部）的 1,044 名巴西人中使用 TaqMan SNP 基因分型分析系统验证与 (SLE) 和 (RA) 的易感性和临床表现的关联。我们观察到隐性模型 (GG x AA+AG) 对 RA 易感性的保护作用以及 AG 基因型患者发生糜烂的风险增加。没有观察到 SLE 易感性的显着关联；然而，我们观察到 G 等位基因和 GG 基因型患者发生 IV 和 V 类肾炎的风险显着增加。总之，我们展示了CIITA rs3087456 对研究人群中 SLE 或 RA 临床特征和 RA 易感性的贡献。