[Evaluating type I interferon-inducible gene expression in patients with systemic lupus erythematosus.].

Objective: To explore the expression levels of interferon-inducible genes in patients with systemic lupus erythematosus (SLE), and to validate these gene expressions as potential biomarkers for the differentiation of disease flare and infection.

Methods: Peripheral blood was obtained from 48 SLE, 16 rheumatoid arthritis (RA) patients and 26 normal controls, and total RNA was extracted and reverse transcribed into complementary DNA. Real-time PCR technique was used to determine the gene expressions of MX1, OASL, OAS1, ISG15 and LY6E at transcription level. Univariate logistic regression analysis and multivariate conditional logistic regression model were applied to analyze 5 related factors for infection or activity.

Results: (1) The expression levels of MX1, OASL, OAS1, ISG15, and LY6E mRNA in SLE patients were significantly increased as compared with normal controls (P all < 0.01), while the expression levels of OASL, OAS1, ISG15 and LY6E mRNA in SLE patients were also higher than those in RA patients (P all < 0.05). (2) There were no significant difference between male and female patients of the 5 gene expression in SLE patients. (3) By logistic regression analysis, ISG15 and LY6E were independent risk factors for active SLE patients (P < 0.01), OASL expression was an independent risk factor for SLE patients with infection (P = 0.003).

Conclusion: All the 5 interferon inducible genes are highly expressed in SLE patients, in which ISG15 and LY6E are independently associated with disease flare, while OASL may be helpful for the evaluation of infection in SLE patients.