Objective: To investigate the expression levels of lymphocyte antigen 6 complex, locus E (LY6E) and interferon-induced protein with tetratricopeptide repeats 1 (IFIT1) genes in the peripheral blood mononuclear cells (PBMCs) of patients with systemic lupus erythematosus (SLE), and to evaluate the relations between these gene expression levels and disease activity.

Methods: The clinical data of 144 SLE patients, 27 non-SLE patients with rheumatic diseases, and 59 normal controls were collected. The SLE patients were further divided into 2 subgroups: active SLE group (n = 87) and non-active SLE group (n = 57) according to SLEDAI scores. Specimens of peripheral blood were drawn; total RNA was extracted and transcribed into cDNA. Sybr green dye based real-time quantitative PCR method was used to compare the expression levels (indicated as-DeltaDeltaCT value) of LY6E and IFIT1 in patients with SLE and those in the controls.

Results: (1) The-DeltaDeltaCT value of LY6E expression level of the SLE patients was 5.4760 +/- 1.9806, significantly higher than those of the non-SLE patients (3.4323 +/- 1.7456) and normal controls (4.5198 +/- 1.6359, both P = 0.001). (2) The-DeltaDeltaCT value of LY6E and IFIT1 mRNA expression of the active SLE patients were 6.1960 +/- 1.7729 and 6.4997 +/- 2.6297 respectively, significantly higher than those observed in the inactive SLE patients (4.3770 +/- 1.7764 and 4.1327 +/- 2.6044 respectively, both P = 0.000). The-DeltaDeltaCT values of LY6E and IFIT1 mRNA of the SLE patients were correlated with the SLEDAI scores, and with the numbers of matched criteria used in the diagnosis of SLE (P < 0.001).

Conclusion: As IFN-induced genes, elevated expression of LY6E mRNA is specific to diagnosis of SLE. The real time expression levels of LY6E and IFIT1 genes are associated with SLE disease activity. To inhibit the expression of LY6E and IFIT1 may become a novel therapeutic approach for SLE.