Purpose: Behçet's disease (BD) is a common uveitis entity in China. The endoplasmic reticulum aminopeptidase 1 (ERAP1), has a significant influence on the stability and immunological properties of MHC-I loaded peptides. In the present study, we investigated the association of ERAP1 gene polymorphisms with BD in a Chinese Han population.
Methods: A two-stage case-control study was carried out in 930 BD patients and 1704 healthy controls. Seven single nucleotide polymorphisms (SNPs) of the ERAP1 gene were determined using a PCR restriction fragment length polymorphism (PCR-RFLP) assay and one SNP was genotyped by TaqMan SNP genotyping assay. Furthermore, ERAP1 expression in peripheral blood mononuclear cells (PBMCs) was examined in genotyped individuals by real-time PCR.
Results: The result demonstrated that the frequencies of the A allele of rs1065407 and C allele of rs10050860 were significantly decreased in BD patients (Pc = 8.5 × 10-8, OR = 0.51; Pc = 1.1 × 10-5, OR = 0.54, respectively). No significant association was observed for the other six SNPs. ERAP1 expression in AA carriers of rs1065407 and CC carriers of rs10050860 was higher than that observed in AC/CC carriers (P = 0.022) or CT/TT carriers (P = 0.018) by LPS-stimulated PBMCs, respectively. In addition, the expression of ERAP1 in active BD patients not receiving immunosuppression was significantly lower than that in healthy controls (P = 3.8 × 10-4).
Conclusions: Our study showed that rs1065407 and rs10050860 of the ERAP1 gene may contribute to the genetic susceptibility of BD by modulating the expression of ERAP1.