Clinical association of FKBP5 gene in systemic lupus erythematosus patients

This study aimed to determine the impact of genetic variation in FKBP prolyl isomerase 5 (FKBP5) on mRNA and protein expression levels, on glucocorticoids (GC) responsiveness and its clinical association in systemic lupus erythematosus (SLE). The genotyping of the FKBP5-rs1360780 was performed using TaqMan SNP genotyping technology. The mRNA expression level in peripheral blood mononuclear cells was evaluated using realtime-PCR. The immunohistochemistry staining was used to analyze FKBP5 protein expression level in renal biopsies. A risk association was revealed between rs1360780 > C allele and SLE pathogenesis. We found an up-regulation in the FKBP5 mRNA expression level in SLE patients with the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score ≤ 6 compared to patients with SLEDAI score > 6. Our results revealed an altered renal cell expression of FKBP5 protein in patients with lupus nephritis compared to control samples. However, no association was observed between the FKBP5 and the response to GC treatment. Our study is the first to demonstrate a link between SLE and FKBP5 gene, in terms of mRNA and protein expression levels, and the variant of the SNP rs1360780 in SLE, suggesting a susceptibility role of rs1360780 > C.